THE LIBRARY OF THE UNIVERSITY OF NORTH CAROLINA THE COLLECTION OF NORTH CAROLINIANA C375.5 N87p UNIVERSITY OF N.C. AT CHAPEL HILL 00034037845 This book must not be taken from the Library building. Digitized by the Internet Archive in 2011 with funding from Ensuring Democracy through Digital Access (NC-LSTA) http://www.archive.org/details/scienceresourceb1958nort > c a resource bulletin NORTH CAROLINA PUBLIC SCHOOLS '7 do not know what I may appear to the ivorld; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smooth pebble or a prettier shell than ordinary, ivhilst the great ocean of truth lay all undiscovered before me." — Sir Isaac Newton, 1642-1727 SCIENCE a resource bulletin for grades 9 - 12 Issued by the: STATE DEPARTMENT OF PUBLIC INSTRUCTION RALEIGH, NORTH CAROLINA 1958 PUBLICATION NUMBER 3 20 -re:;: T <;,... L HE ' HUMAN BOD FOREWORD The scope of science is expanding at an accelerated rate. Within the past few years advances that stagger the imagination have been made on the scientific front. Through the development of precision instruments, the scientist is now able to look out into space to a distance in meters of 10-"' and to probe into matter to estimated dimensions of 10- lr ' meters. As a result of these ad- vances, the student should gain more insight and more apprecia- tion of the infinitesimally small particles of matter and of the immensely large distances of space. Science is truly an "endless frontier". But there is another dimension of science ; science and its asso- ciated technology is an instrument of social change. To appre- ciate the vast changes wrought in the basic fabric of society, one needs only to look at what scientists have uncovered in their study of energy and how technology has used these findings. In 1950 about 85 % of the industrial power was supplied by ma- chines; in 1850 about 5 r < of the industrial power was supplied by machines. To the sources of power commonly used by indus- try, there is now being added nuclear reactors, with their multi- tudinous opportunities. Since the high school is a basic element in society, it must take a critical look at its function and come forth with an instruc- tional program consistent with these scientific advances. The sudden diffusion of scientific information during the past 15 years through newspapers, magazines, and books has over- whelmed and even frightened many persons. To remedy this sit- uation, the high school must place more emphasis on the method of intelligence in the interpretation of science. In addition, the modern high school, if it is to perform its duty in a democratic society, must provide more than the study of bare facts ; science must be perceived as an important factor in our cultural life — for what man's mind creates, man's mind must also control. This publication is an attempt to bring together information and ideas which will tend to promote quality science teaching in North Carolina high schools. An outline for each of the sciences appears in Chapter II. These outlines are presented in question form with the view that the appropriate answers to these ques- v^ tions will constitute the course of study. The other chapters are designed to enable the science teacher to answer these questions more adequately, and thus more effectively to fit the course of study to the needs of our youth. I wish to express appreciation to all members of the staff who have contributed to this publication and especially to Henry A. Shannon, Adviser in Science and Mathematics, and to Herbert E. Speece, in charge of Science and Mathematics Education at N. C. State College, for leadership in developing the material. I express appreciation also to Vester M. Mulholland, Director of Research and Statistics, and L. H. Jobe, Director of Publications, for the careful editing of the material. State Superintendent of Public Instruction August 1, 1958 Contents Foreword 3 Chapter 1. Quality Teaching- in Science 6 2. Courses of Study in Science 33 3. Experimentation in Science 71 4. Science Projects and Science Fairs 107 5. Some North Carolina Resources for Teaching Science . . . 131 6. Physical Facilities for Teaching Science 167 7. Supplies and Equipment for Science 195 8. Safety in the Science Laboratory 241 9. Evaluation of the Outcomes of Science Teaching 256 10. Reading Materials for Students and Teachers 268 CHAPTER 1— QUALITY TEACHING IN SCIENCE The First Two Weeks of School Knowing the Pupils Class Management Developing Security Among Pupils Suggestions for Activities During the First Two Weeks Planning the Year's Work — Value of a Calendar Teaching Aids Science Fairs Science Talent Search Meetings and Conferences The Importance of Words and Ideas Using Questions Effectively Learning Through Problem-Solving Rewards of Quality Teaching Quality Teaching in Science Knowledge of science and the development of the scientific attitude have always been important in the secondary school program, but never more important than today. From the science classrooms in North Carolina go each year potential scientists, science teachers, doctors, technicians, political leaders, and think- ers for tomorrow. In the realization of this fact, is it too much to expect science teachers to be challenged by the tremendous possibilities which each year come to them through their subject areas and through their pupils? For 180 days the science teacher and the pupils are together. In itself this fact seems too commonplace to arouse any degree of excitement; yet when one considers what might be accom- plished during these 180 days, there is every reason for excite- ment and genuine optimism. What are the goals of the science teacher ? Of the pupils study- ing science? To what degree are teacher and pupil goals coinci- dent? What subject areas will be of most interest and use to those enrolled in classes? How shall these subjects be presented? Will all pupils have identical assignments throughout these 180 days? What attitudes and habits of working and thinking will result from these days together? How many pupils will develop skills in analysis and critical thinking? For how many pupils will the scientific attitude toward identifying and solving prob- lems become part of their daily lives ? How many pupils will pursue science further after these 180 days? Not only are the number of days together important, but the number of pupils with whom the science teacher is expected to work is also significant. For the purpose of encouraging quality teaching throughout all the sciences, a number of schools have felt it wise to limit pupil enrollment to approximately one hun- dred pupils per teacher. Perhaps this should be a goal for more and more schools. If this is a reasonable and practical goal, it should not be hastily discarded as something too ideal toward which to work. Some day the slogan of science teachers, pupils, parents, and administrators might well be "One Hundred Pupils for 180 Days !" Perhaps there is no such thing as an average science teacher or an average teaching situation; and certainly there are very few ideal situations. This suggestive bulletin, it is hoped, will have practical and useful ideas for all science teachers in North Carolina — whether the beginning teacher or the experienced teacher ; the teacher in a small community or the teacher in a city school ; the teacher who has all classes in one or more sci- ences or the teacher who teaches science as well as some other subject matter area. The First Two Weeks of School The philosophy of a good start being half the race is just as applicable to the teaching of science as to other situations. To a great extent, the tone of the science course will be developed during the early weeks of school ; and efforts to alter this tone significantly later in the year will be difficult. There is no set pattern, of course, for accomplishing the general objective of quality teaching in science, but some of the following ideas may be worthy of consideration: The science teacher, no less than other teachers, should become intimately acquainted with the routine tasks pertaining to the opening of school. For practically all teachers, these tasks will include meeting classes ; obtaining class rolls ; giving students information about book fees and other possible fees ; collecting fees ; counseling certain students concerning course work, con- flicts, and other problems ; distributing books and other mate- rials ; assigning seats, working locations, and storage spaces, as well as charting this information ; discussing with students over- all objectives of the course along with certain immediate goals ; and, in general, helping all students sense a feeling of friendli- ness, cooperativeness, and eagerness to learn. Knowing the Pupils. In addition to these ever-present respon- sibilities of the opening days — responsibilities which might be classed as routine — there are other responsibilities which teach- ers must also recognize, since these, too, will affect all other efforts for the remainder of the year. Of primary importance is the necessity for the teacher's learning as much as possible about pupils just as soon as possible. Seating arrangements may be useful as the teacher is learning names ; cumulative records may be invaluable as the teacher seeks to know the abilities, interests, and personalities of his pupils. The free-conversational approach to planning the course, both as to group and individual objec- tives, may be profitable. Some teachers have found that having special information cards filled in by pupils results in more up- to-date and valuable information than almost any other tech- nique. Such cards or sheets might include such items as the fol- lowing : Name, age, sex Summer activities — jobs, trips, etc. What sports do you like to play? What hobby or hobbies do you have? Do you like to make things with your hands? Do you enjoy working with machines, such as cars, tractors, and lawn mowers ? What type of books do you like most; animal; mystery and sports; western; Indian and pioneer; war and history; comics; aviation; biography ; other ? Name a book which you enjoyed reading during the past year ? Name a magazine which you like to read. When do you do most of your reading? What is your favorite TV program ? When do you study? Do you study with the TV or radio playing ? Do you enjoy writing, drawing, making talks ? What work would you like to do when you complete your schooling ? Why are you taking this science course ? These and other such items often may elicit information from pupils which the teacher, early in the year, may use in developing effective pupil activities, excellent teacher-pupil rapport, and a desire to do one's best. Facts from these information cards may help the teacher in recognizing those pupils who might be relied upon for improvising apparatus, for illustrating with drawings certain work going on in the classroom, and for becoming group leaders. Such information can be of great value in striving for superior learning situations in the classroom. Quality teaching in science demands that the teacher knows his pupils, and efforts in this direction must begin with the first contacts between teacher and pupils. Class Management. Equally important as knowing one's pupils as early as possible is the necessity that class management, from the beginning, be characterized by firmness, fairness, and friend- liness. Over the years surveys have indicated that pupils respond positively to firm yet fair relationships, particularly when pupils and teachers seek to establish achievement goals and inter- personal goals cooperatively. A climate conducive to superior scientific work in the classroom can readily be achieved during the early weeks of school if the teacher is aware of the great importance of all aspects of class management. Quality teaching in science depends on effective class management ; and this re- sults when there is great respect for self and for others, when purposes are cooperatively determined, and when pupils recognize in their teacher a friendly helper. Developing Security Among Pupils. Effective class manage- ment, such as that described above, can in itself do much to help develop security among pupils in the classroom and, indeed, this feeling of security has long since been recognized as basic for effective learning. It is important also, in helping to develop this feeling of security, that lessons be carefully planned and that pupils know exactly what is expected of them as a group and as individuals. A climate conducive to learning must be character- ized by friendliness, firmness, and fairness if pupils are to sense security in the classroom. Without this feeling, time which should be spent on scientific pursuits will be idled away in uncertain efforts and in activities without purpose. The antithesis of se- curity is intellectual and emotional frustration which completely forbids effective learning. Pupils tend to develop a feeling of security when the teacher seldom makes hasty conclusions concerning the actions of pupils, but rather withholds his conclusions until all facts are known. Frequently there are factors outside the classroom that affect the behavior and academic efforts of pupils within the classroom. In recognizing this fact, the wise teacher forever seeks to become acquainted with all factors which might influence the learning process under his supervision. When pupils are aware that this type of philosophy is being practiced in their very midst, it is natural for deep feelings of security to develop. Mutual respect seems fundamental for this positive feeling of security. Evidences of security in the teacher invariably engenders security among the pupils. Security is developed not only by what the teacher says, but by the manner in which he says it and by the attitude which permeates all his actions. Careful, day-by-day planning on the part of teachers, preferably with pupils participating, likewise helps to set the stage for rich science work throughout the year. Even on the first day of school when periods may be very brief, the purposes of the science course should be clearly understood and activities pertaining to science should begin immediately. Quality teaching in science is more nearly possible when there 10 are strong feelings of understanding between pupils and teach- ers — feelings which permit pupils to move forward with purpose- fulness, determination, and security. Suggestions for Activities During the First Two Weeks. Every science teacher knows of some successful activity in which he and his pupils have engaged early in the school year, hoping through this activity to stimulate individuals and the total group toward other worthwhile activities for the remainder of the year. If these ideas could be pooled, the list would likely be wel- comed and quite helpful. In the Science Teacher for the months of April and September, 1954, there appeared a number of sug- gestions by outstanding science teachers concerning the "First Week of School in Science — A Symposium of Ideas and Expe- riences." The following suggestions are quoted from this maga- zine : Among the goals which have been set up for myself and the boys and girls whom I am to meet are ihese: To meet the routine requirements of opening school. To give the boys and girls an opportunity to meet and begin to know me, their teacher. To become acquainted with these boys and girls. To offer the students an opportunity to develop the feeling that they are an important part of the group and have a significant role to play. To review the science background of each boy and girl. To determine their present science interests and needs. To "set our teeth" into a unit of work which they feel should be explored. Just as soon as the class had decided that living things need air, they came in to see me sealing a snail and some Elodea into a test tube of water — blue water at that. They protested that the snail would die; asked how long it could live sealed up like that, why was the water blue, and what was the plant. To the first question, I answered that they could wait and see for themselves, and suggested simple pro- cedures for making observations and keeping records. I told them I put bromothymol blue into the water and offered them the means and opportunity of testing this chemical to learn about it. I told them the name of the plant. Then I asked them why they said the snail was alive when one of them said it was moving. I rolled a small object across the desk and said, 'So is this.' The rest of the week was spent in determining how we might distinguish between living and non-living things. To impress upon my students the fact that metric measurements are often used to indicate the dimensions, weight, or volume of things commonly found in their homes, I placed on display a collection of cartons, cans, bottles, and wrappers from the kitchen cupboard shelf or from the nearby supermarket. On the labels of all these containers 11 will be found references to the metric system. The labels indicate that a cleansing - tissue measures 22.8 by 24.7 in.; a box of cornflakes weighs 8 oz. or 227 g.; one ounce of another cereal contains .15 mg. of thiamine and 1.275 mg. of iron; there are 88 cc. in a bottle of ink; a can of developing powder will make 3.78 liters of solution ; and a motion picture film is 8 or 16 mm. wide. The students pass these containers around and see for themselves, perhaps for the first time, that metric units really are used in trade. For the next few days the students, gave oral reports on where they spent their vacations. This, of course, calls for mention of anything that may be of scientific importance,, such as planetariums, aquariums, zoos, botanical gardens, geological formations, and medical buildings. The res ponse is always good, usually 100 percent, and is the first step in giving the child an opportunity, to assert himself and contribute to the class discussion. This is all very, informal, with the idea of making the student feel at ease and less withdrawn. Exploring is the keynote of our first, weeks of biology. The first day the room is set up like a science fair with problem-solving types of experiments on the tables, student-made posters on walls and bul- letin boards, exhibits of projects completed by last year's students, an electric game board, a "What Is It?" shelf, a "Believe-It-or-Not" table (i.e., a tomato is a fruit), cages of live animals, and a bookcase full of interest-challenging books (Magic in a Bottle). In opposite corners of the room, former students are ready to project color slides taken on field trips last year, and to show slides of pond water, blood, etc. Under the compound microscope, students are invited to spend the hour exploring the room to find out what they can about biology . . . Another type of field trip we use the first week is the "self-guided" tour of the campus. For this I give the students a list of things to to look for and to do at a number of specific places on the grounds (find the animal inside the gall on the oak leaf, watch the children at play in the park, etc.). Biological scavenger hunts are other good first week field trips which start students to observing . . . Next we spend a few days exploring with a microscope. What better introduction to its use than a drop of pond water full of active pro- tozoa ? With no drawing's to make or reports to give, we can have fun hunting for plants and animals. As on the field trip and room explora- tions, interest is aroused, questions arise. I feel that chemistry is a wonderful place to show how the methods of science are not only useful but a "must" for progress. Therefore, I take time at the beginning of the school year to demonstrate the methods of science in action in industry. We start out by examining a manufactured article, such as plastic tag, a sample of colored cloth, or a sanding disc, and then trace the steps taken in solving a problem pertaining to the article. Let's say that the sanding disc came up for review as a competitive product. We first discuss how the teams of scientists and engineers could examine the product, then make a guess as to how such a product could be made. We try to imagine how these men would think as they endeavored to make a better product. As we discuss this we would have samples to handle and examine just as the engineers might. Next, we would try to find out what tests such a product might be put through. We would discuss testing as it is done in a laboratory and as it might be done in the field. Where do we start? It makes no difference where we start, providing the important concepts are hit during the year. It may be Albino corn seedlings, insects — anything that will fire the enthusiasm of the stu- 12 dents and the teacher and lead to important biological principles. To ask "Shall we start by working with the microscope?" has always aroused intense interest. During that first week we may learn how to use the microscope, prepare infusion cultures, and perhaps make our first examinations with these questions in mind: What part have instruments played in the progress of science ? What has the micro- scope contributed ? How do scientists go about their work in solving problems and making discoveries ? How can living things be so small and yet be alive ? The following idea does not come from the above reference, but is a suggestion which may be useful : One way to capture the interest of students is to prepare something good to eat. If good food can be prepared with an excellent learning- situation in chemistry, why not experiment with this idea during the first two weeks. This suggestion involves the use of two ice cream freezers — turned by hand or by electricity — of the gallon size. Two are suggested because one of them can be used as a control in the experiment. There are several purposes for this experiment: (1) to demonstrate the use of a control in experimenting; (2) to show the effect of a compound (salt) on another substance (ice) ; (3) to show a physical change; (4) to study the composition and food value of a common food (ice cream); (5) to arouse the curiosity of the students. Further suggestions for carrying out this project are: (1) request the home economics class to prepare the ice cream mixture; (2) secure ice and salt; (3) weigh an exact amount of ice for each freezer; (4) weigh the amount of salt to use in one of the freezers; (5) no salt is placed in the other freezer; (6) keep a record of the time needed to freeze the ice cream mixture; (7) record the water temperature in each freezer each five minutes; (8) secure paper cups and wooden spoons to use in eating the ice cream; (9) agree on conclusions through discussions; (10) save the data for further reference and for future experimentation. How profitable can 180 days in a science class be? How much subject matter can be effectively studied? What methods of in- vestigation will be introduced? To what degree will pupils under- stand purposes for studying science? To what extent will an appreciation of the scientific method become part of their daily lives? To what degree will pupils be motivated to pursue the study of science still further? Numerous factors are involved in answering any of these ques- tions completely; yet, by and large, it seems that the following emphases are inescapable if the 180 days in the classroom are to be of most value : 1. The teacher must know his pupils as completely as possible, and must demonstrate his understanding in such ways that each pupil recognizes this. Mutual respect is necessary for satisfactory learn- ing. The pupil must feel that his teacher is well-prepared to teach; that he is interested in science and the development of science; and that he wants, above all else, to help his students grow in scientific knowledge and in the use of scientific methods. On the other hand, the teacher must evince a wholesome respect for each 13 pupil as he is; and must somehow make real this respect by con- stantly finding ways of motivating' each pupil into achievements that parallel his capabilities. 2. Class management must be characterized by a high degree of order- liness and efficiency. Much preplanning on the part of the teacher, and much cooperative planning between teacher and pupils will do much to create an atmosphere in which science teaching and the learning of science can be guaranteed. Here again, the teacher's personality as expressed in everything he says and does must con- vince the pupils of his fairness, his firmness, and his friendliness. Unless this atmosphere prevails in the science classroom, the limit- less possibilities of teacher and pupils being together 180 days cannot be realized. 3. Pupils must feel secure if they are to further their knowledge and interest in science; and the teacher can do much to develop this feeling of security. Acceptance and practice of the two above sug- gestions will almost invariably help students realize the purposes of science and the importance of their knowing more about science. As the teacher finds ways of helping each pupil in the task of self-realization, a sense of personal worth and security will become the great stimulus for unbelievable accomplishments in science. 4. It is important that the stage is set during the first few weeks of school for developing interest and genuine enthusiasm for learning science. For this reason, every teacher should seek to introduce, as early as possible, solid scientific information and techniques in as challenging a situation as possible. To this end, several sug- gestions for use early in the year were listed above as a supple- ment to many others already in the minds of science teachers throughout the State. Planning the Year's Work — Value of a Calendar. Because of numerous activities which must be carried on in all science class- es and because of the many professional meetings and confer- ences which science teachers need to attend, a calendar should be developed for the work of the students and for the teacher. The most important aspect of this job is to arrange in effective sequence the units of work in the various science classes. As the work of the year progresses, it might be necessary or desirable to rearrange some of these units because of student interests and needs; nevertheless, such preplanning is necessary if the most is to be made of the 180 days. Without perspective which comes from preplanning, the course might easily develop into a page-by-page coverage cf the textbook ; or it might result in the stressing of only a few of the important scientific concepts, thereby leaving out others that should be studied. If the students are to receive a well-rounded worthwhile course, it must be planned in the mind of the teacher. All the parts of the whole must be fitted together in such a clear manner that students themselves will be aware of the unity and organization in the course. 14 Teaching Aids. Another reason for intelligent planning far in advance is to enable the teacher to have the various teaching aids available when they are needed. Carefully selected motion pictures can do much to clarify many difficulties which students may have, but they must be shown at the proper stage in the study of a particular unit if they are to fulfill their purpose. To have these films on hand when they will be most effective, the teacher will need to send in the film requests several weeks or months before they are to be used. Requesting films haphazard- ly, as the idea comes to the teacher, will often result in their haphazard use and in haphazard results. If the school unit has a film library, then it is easy to know its listings and how to pro- cure those films desired. If the school participates in a rental system, then a careful study of the film catalog will need to be made as early as possible, perhaps during the summer before school opens. If films are to be obtained from industrial concerns or from governmental agencies, catalogs or lists of the films must be readily available. Good library materials are essential for a modern science pro- gram. In planning the year's work, it is important to remember that the responsibility for requesting the most useful materials for use in the science classes rests with the science teacher, who will find the school librarian willing to cooperate. One cannot expect the librarian to be familiar with all the new science books, films and other materials which are being produced; but, by working together, the science teacher will have access to many new materials and to many reviews of potential materials. Since the main order for books is often placed in the fall of the year, the science teacher should file his requests with the librarian as early in the school year as possible. This will enable science students to have the newest materials at their disposal as efforts are made early in the year to encourage a continuous reading and research program. A number of suggestions for reading ma- terials are given in the section of this bulletin dealing with this topic. Science Fairs. As plans are made for the year's work, the teacher should be aware that science fairs are proving to be strong incentives for students in doing research work and in preparing worthwhile exhibits. There is one section of this bulle- tin devoted specifically to this activity. A careful reading of this 15 portion of the manual should provide a number of ideas which may be useful to science pupils. On the calendar for the year should be placed a reminder that science fair projects should be initiated as early in the fall as possible. Some students actually begin their research in the summer; but all students should get an early start during the fall in their research, thereby leaving time in the spring for finishing touches to exhibits. Science Talent Search. In planning the year's activities, the science teacher should keep in mind the Westinghouse Science Talent Search and the North Carolina Science Talent Search. More and more emphasis is being placed on these worthwhile activities. These contests, open only to seniors, must be antici- pated years in advance if tangible results are expected in the senior year. It is important, therefore, that the teacher detect science talent in the ninth grade, or earlier, and then try to nur- ture this talent during the remaining years in high school. If this is done, the pupils will be prepared to enter the contests in December of their senior year. Likewise, the pupils will be ready to enter the Science Achievement Awards Program sponsored by the National Society of Metals. Entries for this contest must reach the headquarters of the National Science Teachers Asso- ciation in the early spring. Meetings and Conferences. In making out the year's calendar, the science teacher should recall that there are important meet- ings and conferences during the school year which he should attend. Beginning in the early fall, the North Carolina Education Association and the North Carolina Teachers Association hold their district meetings. At each of these district meetings there is a program for science teachers lasting for approximately two hours. These programs are planned by the officers of the science teachers in each district. These same organizations hold their State meetings in the spring of the year, and again the science teachers have a carefully planned program. These dates should be marked on the calendar and plans made accordingly. On the national level, there are also outstanding conventions and conferences for science teachers. The first of these, held be- tween Christmas and New Year's Day, is the annual meeting of the American Association for the Advancement of Science. As a part of this convention, the National Science Teachers Associa- 16 tion and the American Biology Teachers Association, affiliates of the AAAS, have an outstanding program. During the latter part of March, the National Science Teachers Association holds its annual convention. Many outstanding science teachers and scientists participate in this four-clay convention. These annual conventions have proved to be so outstanding and helpful that, once a teacher attends, he tries never to miss another one. Although all of the items which should be on the science cal- endar are not discussed here, those mentioned will suggest that a science teacher would likely profit a great deal by preparing some type of calendar in order to remind him constantly of the many activities for which plans must be made. Quality teaching in science cannot be a hit-or-miss proposition ; it must be on the target. Planning work in science a year in advance gives the teacher security which he also needs. Such advance planning, as men- tioned above, does not preclude modification in plans as the year progresses ; moreover, it serves to bring a type of unity and or- ganization to the program which can never be achieved through casual, day-by-day planning. Such planning is helpful to pupils also, since it enables them to comprehend something of the total program and its purposes. Advance planning can provide many opportunities for correlation of learning experiences throughout the school, providing teachers have learned to work together in this manner. The science calendar is suggested as an aid in becoming aware of the total job to be done, hoping through such a device that pupils and teacher will find their 180 days together as full of meaning as possible. The Importance of Words and Ideas. Quality teaching in sci- ence demands, for teacher and pupils, that words and ideas convey exact meanings. If words mean only what they represent in our experience, then a poverty of ideas may be associated with meagerness of contact with the world of things and persons. In all science classes, pupils will vary considerably in what they will be able to absorb from the printed page, as well as in their ability to do creative thinking. If pupils are to make substantial prog- ress during their 180 days in the science class, then the teacher will have to discover and overcome some of the gaps in their experiential backgrounds. 17 The teacher should consider that an important part of his role as instructor in science is furnishing the background for many scientific terms that will be encountered continually. It is hoped, through this approach, to encourage students to inquire critically for the true meaning of more and more scientific terms. "Tropic." What do ninth-grade pupils understand of the terms "tropic," "tropic of Capricorn," and "tropism" ? To find out, the teacher might give the word "tropic" to the class and immediately ask pupils to say what first comes to their minds when the word is heard. Typical answers will likely include "warm climate," "equator," "rain," "bananas," "alligators," and others — all of which are appropriate, of course. Next, the teacher might ask if any one can give the root meaning of the word. Seldom, it is likely, will the correct idea be furnished. Such a moment is the time, it seems, to impress upon pupils the real meaning of this word. One way to do this might be the following: Ask the stu- dents to imagine a line going down the center of the room and call this the equator. On one side of the room locate the tropic of cancer and on the other side, the tropic of Capricorn. The next element to place in the room is the sun, and this can be the teacher. At this stage in the drama the students must use their imagination and past knowledge to the fullest. The sun is to appear to move in the sky in relation to the three imaginary lines in the room, this moving being determined by a person who is directly beneath the sun (no shadow) at noon time during various times of the year. Suppose this lesson is taking place soon after school starts in September — to be specific, September 22. Ask the pupils to place the sun (the teacher) in the correct relation to the three imaginary lines, assuming a person has the sun directly overhead at noontime on that day. There will be much discussion and shifting of the sun before the class can agree. Next, select a day in October ; then, December 22 ; then, March 22 ; next, June 22, and finally, September 22. While all of this activity is taking place, have the students chart the appar- ent motion of the sun in relation to the three imaginary lines. Ask what appears to happen on December 22 and on June 22. As the thinking of the pupils is prodded by appropriate ques- tions, the teacher will see the eyes of the more rapid learners light up because they begin to grasp the idea. Finally, ask sev- eral pupils to check the word "tropic" in an unabridged dictionary and bring a report to the class. This report will show that the 18 meaning underlying the term is "turning." When this is grasped, there is little hesitation about the word "tropism" and all of its variations. To check on the effectiveness of this lesson, the teach- er might ask a question or two at the end of the school year. For many of the students, it is likely that the meaning will still be remembered. "Dextrose." Many common words are used without any real understanding of their basic meanings. "Dextrose" is a scientific term, yet many people would not classify it as such. In chemical language, "dextrose" is a simple sugar, very often called glucose. The teacher might ask several pupils to look up the word in an unabridged dictionary and also to find several related words. One of the related words will probably be "dexterity," meaning skill- ful. Why is this word used to denote skillfulness. Several will re- member that it was believed that a right-handed person was more skillful than a left-handed person; thus the root word re- fers to the right as right hand is introduced. At this point the pupils will likely be very confused since they see no relation be- tween right hand and dextrose. They will have a good reason to be confused because they have not had the necessary background. Thus, it becomes the responsibility of the teacher to explain briefly the polariscope: how a beam of polarized light is passed through a sugar solution and in order to see the beam through the eyepiece, he must rotate it a certain number of degrees to the right. Before the explanation is completed, some of the stu- dents will grasp the idea ; and, furthermore, they will remember it. ''Humor." Another example of how the science teacher may naturally and effectively explain words and ideas is found in the word "humor". There was nothing the least bit funny about this word as originally used. It was borrowed from the Latin, and in that language "humor" meant a liquid. The ancient philosophers believed that four liquids entered into the make-up of the body and that our temperament (Latin, temperamentum, "mixture") was determined by the proportions of these four fluids or humors, which they listed as blood, phlegm, bile, and black bile. If one happened to have an over-plus of "blood", the first of the humors, he was regarded as of the optimistic and sanguine temperament (Latin, sanguin, "blood"). A generous portion of phlegm, on the 19 other hand, made one "phlegmatic," or slow and unexcitable. One with too much yellow bile was thought to see the world through "bilious" eyes, and since the word "bile" is chole in Latin, such a one was regarded as choleric and short-tempered. The fourth humor, non-existent black bile, was a special inven- tion of the ancient physiologists. A too heavy proportion of this humor made one "melancholy," for in Latin melancholia meant "the state of having too much black bile." Any imbalance of these humors, therefore, made a person unwell and perhaps ec- centric; and, as the years went by, the word "humor" took on a meaning of "oddness" and a humorous man was one that one would now call a crank. Finally, the word was applied to those who could provoke laughter at the oddities and the incongruities of life. "Oxygen." Even though most of the pupils will have a rather clear conception of the nature of oxygen and its impor- tance by the time they reach the ninth grade, the majority will not have sufficient understanding of the history of the element to appreciate it thoroughly. This appreciation is essential if pupils are to grasp the significance of its discovery and relate it to other facets of their learning. In other words, they must known more about it than just the root meaning of the word, which is "acid-forming." This bit of information will be of little value to any of them. To bring about a better understanding of the word "oxygen" the teacher might try to correlate several events in history. This might be done by asking the pupils what the dates are on the North Carolina State Flag. If they do not know, the teacher might have them find this information. They will discover the dates are: (1) May 20, 1775 — Mecklenburg Declaration; (b) April 12. 1776 — Halifax Resolves, First State Action on Inde- pendence. After these facts are firmly fixed in mind, the teacher might ask whether the term "oxygen" was being used in North Carolina at this point in history. After much hesitation on the part of the students, the conclusion will likely be reached that they do not know. At this stage of the discussion, the job of the teacher begins — to picture in a dramatic manner the discovery of oxygen and the overthrow of the Phlogiston Theory. Only a few of the facts concerning this discovery will be given here. For 20 the complete story, one might study the Harvard Case History in Experimental Science called THE OVERTHROW OF THE PHLOGISTON THEORY— THE CHEMICAL REVOLUTION OF 1775-1789. This story begins November 1, 1772, when Lavoisier wrote to the Secretary of the French Academy the following: ''About eight days ago I discovered that sulfur in burning, far from losing weight, on the contrary, gains it; it is the same with phosphorous; this increase^ in weight arises from a prodigious quantity of air that is fixed during combustion and combines with the vapors. "This discovery, which I have established by experiments, that I regard as conclusive, has led me to think that what is observed in the combination of sulfur and phosphorous may well take place in the case of all substances that gain in weight by combustion and calcination; and I am persuaded that the increase in weight of metallic calxes is due to the same cause." Here one sees a flash of genius, since Lavoisier is proposing a theory which says that something is taken from the atmosphere in combustion and in calcination. This theory was exactly opposite to the phlogiston theory. So excited was Lavoisier about this premise that he wished to find out what this something was. As a result, he experimented with gases in a search for the answer; but his efforts were attended with little success until the winter of 1774-1775. He was first put on the right track by his experiments with the red oxide of mercury. It was in August of 1774 that Priestly prepared oxygen by heat- ing red oxide of mercury, but he was mistaken about the new gas because he thought it was "laughing gas." In October of the same year Priestly told Lavoisier of his experiment. As a result of these comments and much additional experimentation, Lavoisier was able later to substitute a "constituent of the atmosphere which supports combustion" for the "something" which he formerly used. Even though it was Lavoisier who finally realized that he had discovered a new constituent of the air and that it supported combustion, Priestly actual- ly made the effective discovery of oxygen in March of 1775. But Priestly stuck to his belief in which phlogiston was the determining factor in calx (oxide of metal) formation, even though he had the correct facts. If the teacher and pupils pursue the study of the discovery of oxygen by Priestly and Lavoisier, there will gradually develop a better appreciation of the efforts which went into this work, a better understanding of a major development in chemistry, and a better insight into the nature and meaning of oxygen. In addi- tion, the knowledge that this important scientific event was tak- ing place about the same time as two important historical events in North Carolina should impress these facts upon students to the extent that more permanent learning will result. A further advantage will likely be that pupils will handle the bottle of red oxide of mercury in the laboratory with more respect, since they will appreciate the effect on history of the experiments made with this common material. 21 Other Areas. This strengthening of the meaning of words and ideas in science may have its effects in other areas of study ; and similarly, other areas of study will have a pronounced effect on science. There are many beautiful pieces of literature — poetry, prose and drama — which, if read with full appreciation, demand that the pupil have a background in science that will enable him to grasp the meaning. One such poem is "The Chambered Nauti- lus" by Holmes, the last stanza of which follows : Build thee more stately mansions, My Soul, As the swift seasons roll! Leave thy low-vaulted past! Let each new temple, nobler than the last, Shut thee from heaven with a dome more vast, Till thou at length art free, Leaving thine outgrown shell by life's unresting sea! How will a pupil be able to read this with understanding unless he knows what a nautilus is and something of its life-history. If this poem is being studied in an English class, pupils from a biology class might furnish the necessary background in order that the stanza or entire poem might take on new meaning. It is interesting and enlightening to have the following poem read by two pupils : by one who takes little from the printed page because of his poverty of words and ideas ; by another who has begun to appreciate the marvels of nature as expressed by words on the printed page. For one, the experience will be deadening; for the other, it will be a joy. During the 180 days of experiences in science, students, it seems, should grow in the ability to handle literature of this type: NATURE STUDY By James G. Needham, Professor Emeritus, Cornell University The trees and the skies and the lanes and the brooks Are more full of wonders than all of the books; And always out-doors you can find something new; You never are lacking for something to do; You never hurt others, or get in the road In taking the pleasures by nature bestowed; For there's room on the shore where the great tides roll, And freedom and peace that are good for your soul; There's hardly a way you can have so much fun As in being out-doors with the brooks as they run, With the birds as they fly, and the stars as they shine, With the drift of the years as they rise and decline. It doesn't cost much and it doesn't take long To get your ear tuned to the mighty world's song. It brings in its train no unpleasant regrets, And the further you go, the better it gets. So, come where the wild things are waiting outside And let your soul taste of the joys that abide. 22 Another approach to the study of words from a different point of view is found in an article written by Hanor A. Webb, en- titled, "How Do You Pronounce 'Laboratory'?", published in The Science Teacher for December 1951, p. 285-286. The follow- ing are excepts from this article: "Labor" in the Laboratory Originally laboratory was spelled elaboratory. The word comes directly from the Latin language, and means "out of labor," implying a place where things are made by work. The word labor is Latin for "be weary." Yes, to work hard and get tired seems to be the lot of man. The wise men of every age have told us to expect no easy way. Said Sophocles (B.C. 4967-406) the Greek philosopher: "Without labor nothing- prospers . . ." Then, not too long ago, the talented artist and writer, John Ruskin (1819-1900) of England expressed this philosophy: "If you want knowledge, you must toil for it; if food, you must toil for it; even if pleasure, you must toil for it." All this makes plain the first emphasis of the laboratory. It is a place to do productive work. "Oratory" in the Laboratory How many persons there are who would rather talk than work! Such persons — and they include many science students — have the impulse to argue a thing out before they test it. Even though the discussion takes more time, and may lead to wrong conclusion, yet they seem to find talking easier, or more pleasant, than observation . . . Even teachers sometimes talk too much in the laboratory. They inter- rupt too often. Although teachers should ask questions and give ad- vice to individuals when it is needed, much of their laboratory time should be spent smilingly watching their students at work. "Rat" in the Laboratory The "rat" in the laboratory is waste . . . Students with little laboratory experience are almost sure to take solutions and dry chemicals from their bottles in wasteful amounts. But why bring a tablespoon of sugar for a sugar test that requires only a pinch? . . . In some laboratories there is a great waste of filter paper, paper towels, and even of water. All too often there is a great waste of time — but that is the next topic. "Bor(e)" in the Laboratory Boredom is due to a slow-down in the procession of interesting ideas that pass before our attentive selves. It is up to us to keep our atten- tion keen! Many students get tired in the laboratory and dislike it. The reason is that they do not remain alert to what is happening. Good students — the wide-awake ones — enjoy their laboratory hours. "A scholar knows no boredom," wrote the German novelist Jean Paul Richter (1763-1825). Work in a laboratory should never be under great pressure, causing hurry, flurry, and worry. It should be under mild pressure to com- plete reasonable assignments in full during the period, which may be accomplished by attentiveness, smartness, and carefulness. But if indolence, dawdling, inattention, and wasters of time are evident, the laboratory will have plenty of boredom in it. "Tory" in the Laboratory "A Tory" is an extreme conservative in attitude — one who holds back in the face of progress . . . 23 The "Tory" in the laboratory is likely to be the teacher. He may be an extreme conservative. He will try nothing new. For years he has used the same experiments as printed in the laboratory manual, and he cares for no others. Little pieces of the Laboratory Even the small syllables of our key word have meaning for us if we study them. The letters Abor are Latin for "away from your mouth" and seem to warn against careless tasting. The letters lab form an old Scotch word for "your share," so do your share of the work and get your share of the information. The letters la form a French interjection of surprise — there may be many surprises in the laboratory. The preposition at means "in place," which is an important aspect of laboratory housekeeping. The preposition to implies progress toward some goal, and this is a pur- pose in your laboratory work. The syllable ry in Latin indicates a place where things are made and kept for use. What more important idea exists concerning a laboratory than that of a place where the production of skills and knowledge in science is the chief purpose. Using Questions Effectively. More emphasis can be placed on the importance of words and ideas when questions are posed by the teacher in such a manner that memorization will not be sufficient to formulate answers. There is an art in asking ques- tions which will bring out the desired information and at the same time cause pupils to do reflective thinking. If questions are worded in a manner similar to the following ones, there will probably be little thinking: "Could you tell us"? or "Who will tell us" ? Skillful teachers more often begin questions with "what," "why," "how," and "when." As an example of the two approaches, one might ask "who will state Ohm's Law?"; but a better approach might be 'What is the mathematical statement of Ohm's Law?" It is also important to remember that a skillful teacher will answer many of the important questions with other questions. This is particularly important in science, where the questioning attitude is emphasized ; and this is really what scien- tists do : they put questions to nature. Generally, when a scientist finds the answer to his first question, a dozen others equally im- portant also arise. This technique received strong support when Comenius, the seventeenth century educational reformer, said, "The less the teacher teaches, the more the learner learns." To illustrate a more involved type of question, the following example in chemistry is given. This question might be asked after the pupils had become familiar with gases, air pressure, barome- ter readings, temperature scales, and the metric system. Data for this problem follow: "A Laboratory Experiment to Determine the Weight of 22.4 Liters of Oxygen ; weight of oxygen collected 24 — 1700 cc; temperature of gas — 24°C; barometric pressure — 657.8 mm. ; tension of aqueous vapor — 22.2 mm. ; corrected baro- metric pressure — 657.8 mm.; answer — 32.07 grams." This ex- periment was performed at one of the colleges in North Carolina. The question which might be asked by the teacher is : "At which of the following colleges was this experiment performed?" To make a better presentation of the question, the teacher might draw a rectangle on the board to represent North Carolina and place dots in the appropriate places to represent Western Caro- lina College, Appalachian State Teachers College, Davidson Col- lege, A and T College, Duke University, East Carolina College, and Fayetteville State Teachers College. If questions such as the above have not been used often with the science class, and if the teaching has stressed memorization of isolated facts, the pupils will be somewhat amazed at this approach. If questions such as this are used regularly in the science class, there will develop within the pupils the desire to comprehend the full meanings of words and the desire to organize these words so that ideas, concepts, and principles will evolve. Quality teaching in science demands that pupils understand what they read and what they hear ; so, in a very real sense, the science teacher must also be a teacher of language arts. In order to understand a scientific concept, it is often necessary that the science teacher assist pupils in analyzing the exact meaning of words. Exactness in the communication of ideas is nowhere more important than in the science class ; so, as the facts of science are taught and as scientific techniques are emphasized, the effec- tive science teacher, of necessity, becomes a guardian of the language, seeing that it is properly understood and effectively used. In a very real sense, every good science teacher is also a teacher of English, logic, and methods of problem solving. An understanding of the true meaning of words is essential if pupils are to move forward in science ; and this, it seems, is inescapably part of the science teacher's responsibility for each of the 180 days. Learning Through Problem-Solving. Problem-solving as an approach to learning has gained increasing respect through the years, not only by teachers of science but by many other teachers as well. In a sense, problem-solving is a way of teaching, a way of thinking, and a way of learning. In essence, problem-solving sug- 25 gests the bringing together of all pertinent facts which might help to resolve a particular question or problem. This involves searching for materials, weighing their worth, organizing the facts, reaching and verifying conclusions. In problem-solving are the very elements of the scientific attitude toward all learning. In the spring of 1950 the entire program of the fourth annual convention of the National Science Teachers Association was de- voted to "Problem-Solving: How We Learn." For three days the convention participants listened to discussions on: "Problem- Solving— What Is It?"; "Problem-Solving Ability— How Can It Be Acquired?"; "Effectiveness of Problem-Solving Education — How Can It Be Evaluated ?" If problem-solving was considered so important by a national convention of science teachers, then, it seems, it should be worthy of careful study by all science teachers. When learning takes place there is change in behavior. In science classes, during this period of 180 days, the task of the teacher is to work with all pupils so that changes in behavior do take place and so that pupils are guided into profitable and worth- while directions. How does this learning take place? In the book The Learning of Mathematics — Its Theory and Practice, pub- lished by the National Council of Teachers of Mathematics, Washington, D. C, 1953, p. 7 and 8. there is an excellent discus- sion of this topic. At the start of learning or readjustment of behavior, there must be a situation in which the student feels a need. A need is the feeling of the organism for something which is absent, the attainment of which will tend to give satisfaction. The situation is such that the student is motivated to satisfy a need. This creates tensions and drive within the organism which impel it toward its goal. Thus the learner is spurred to physical and mental action, or making a response. The first response often does not lead to the goal; he runs against a barrier. If the motivation to learn is strong enough, the learner seeks another response or series of responses. One after another of these responses may fail to lead to a solution, but finally he selects a path of action that reaches the goal. He has solved the problem; he is ready to readjust his total behavior in this situation. He may go over the solution, to make the meaning and structure more precise, and his formulation more articulate; to make the whole situation more highly differentiated from previous learning, and more generalized until he has developed a new pattern of behavior that will function in new problems containing the same or similar situations. He has learned. Helping students to learn and thus bring about desirable changes in behavior is not a simple job that can be left to chance, as the above discussion clearly indicates. The first problem-solv- ing situation for the teacher is to help students want to know 26 more about a particular topic. If there are 27 pupils in a biology class, it is well known that the backgrounds, interests, and ca- pacities will vary considerably ; thus, that which is a problem to some of the pupils will be no problem to others. This implies that, though the teacher may begin with the class at a certain point, within a few days there will be a wide range in the accom- plishments of the pupils. If worthwhile problems are to be faced by the pupils, the teacher will have to make extensive use of supplementary books, library materials, experimental work, and project work. The use of these techniques will enable the teacher to provide learning situations on a variety of levels; good ques- tions will aid in directing individuals or groups of students to investigate particular topics. This is of special importance for the more rapid learners in the class ; and is clearly illustrated in the concluding statements of "A Symposium on Science Provi- sions for the Rapid Learner," as reported in the November 1953 issue of The Science Teacher. Some of the conclusions mentioned in this article follow: • Subject matter of increasing difficulty must be provided to furnish challenging situations and to encourage the student to work to his highest capacity. • The generous use of the library and supplementary ma- terials are indicated to create a keen interest in science. • It is desirable that provision be available for extra labor- atory work and the opportunity for creative project work. • Reading reports and the science-writing aspect on items of special interest are necessary to increase the wide range of activities of the rapid learner. • The rapid learner can work with more freedom and should assume a greater responsibility for his own school activities. • Hobby activities should be encouraged. • Opportunities to assist the teacher in the capacity as laboratory assistant or "science dispensor" give the rap- id learner the feeling of constructive action and a sense of participation. • A close relationship between a teacher acting as a sci- ence advisor and the rapid learner is usually productive in the more advanced areas of knowledge and encourages the student to extend himself. 27 In most discussions concerning science education two terms continually appear: "interest" and "need." There is nothing wrong with the terms ; the only trouble with them is the very general use to which they are put. In many cases the teacher can do a bit of juggling and arrive at the conclusion that students need what the teacher has been teaching all the time. If such a conclusion is reached, then the teacher can say that the suggest- ed courses of study presented in this bulletin, or those found in many other publications, supply the needs and interests of all the students taking science. If this were true, then many of the problems facing teachers and students could be easily solved. But, the carefully planned structural organization of science education is not as important as what the teacher and pupils do daily in the classroom for the 180 days of the school year. It is possible to have a completely planned program in science with all the supplies, equipment, books, and motion pictures and still fail in the educational task. As has been said, "Where we are going in science education depends on whether we are drifting or whether w r e have a head of steam to take us where we want to go." This suggests that the science teacher must fix firmly in his mind several important goals toward which he will strive at all times as he works with his students. This cannot be done un- less the teacher also has a picture of what science is ; that "stripped of all but its bare essentials, science becomes nothing more than a method of discovering new facts ; and since no single fact can exist alone, science must, of necessity, lead to the discovery of new relationships." Or, as Dr. Conant has said, "We shall define science as a series of concepts or conceptual schemes (theories) arising out of experiment or observation and leading to new experiments and observations." To provide teachers with a base for the development of their own ideas about goals of science education, the following sugges- tions by Curtis in the article, "Basic Principles of Science Teach- ing," The Scierce Teacher, National Science Teachers Associa- tion, Washington, D. C, March 1943, are presented: • The fundamental basis for determining the objectives of every science course 'as indeed of every course in ev- ery field' is a consideration of the nature of the TRAIN- ING that the course is intended to provide. • The stated objectives of any science course are appro- priate only if the means by which they can be imple- 28 mented have already been devised, or can, with reason- able certainty, be invented. • Science education at every level should be organized and presented so as to develop skills in reflective thinking and problem-solving. • Science education at every level should be organized and presented so as to stimulate, guide, and develop scien- tific interests, attitudes, and appreciations. • The achievement of every objective of science must be- gin with the building of understandings. • The facts that are introduced into a science course or are planned for discovery in it, should be primarily se- lected so as to facilitate the development of understand- ing of scientific principles or generalizations. • The essential materials to be taught in any course should be rigorously limited to an amount that can be taught thoroughly. • Meaningful learning starts with a problem in the learn- er's mind and involves exploration and discovery by the learner. • In every science course, use should be made of both the inductive method and the deductive method of teaching. • In harmony with the democratic conception of educa- tion, every individual is entitled to his just share of attention and effort directed toward developing his max- imal potentialities. • Evaluation must be continuous, not only the evaluation of pupil achievement, but also the evaluation of the ap- propriateness and effectiveness of the teaching methods, procedures, and devices employed. • Since, in learning as in practically every other endeavor, an individual's most valuable assets are time and energy, the learning experiences should be planned to achieve the desired goals with the maximum economy of time and effort. • Optimally effective group learning is possible in a class only when its members are brought to realize that par- ticipation in the class activities is both a privilege and an obligation. • Effective teaching is achieved through the use of a vari- ety of materials and procedures. Psychologists affirm that we become defeated not so much by continued hard work, as by the monotony of unvaried work. If the development of problem-solving abilities, which includes critical and reflective thinking, is an important goal in science education, the teacher should have a grasp as to what is involved in this matter and should have a guide of some type to use in checking his progress and that of the students toward this goal. 29 The previous discussion brings out many of the factors which are related to work involved in the problem-solving process. A very detailed analysis of this aspect of learning has been prepared by Dr. Darrell Barnard of New York University and Dr. Ells- worth Obourn of the U. S. Office of Education. The title of this report is "An Analysis and Check List on the Problem-Solving Objective" ; it has been printed as Circular No. 481 by the U. S. Office of Education, Washington, D. C. The section dealing with "The Inventory of Problem-Solving Practice" is given here with the hope it will be of value to teachers in determining how well science pupils have progressed in this area of instruction and in determining ways to strengthen the science program for the following year: A. Sensing and Denning Problems To what extent do you: 1. help pupils sense situations involving personal and social problems? 2. help pupils recognize specific problems in these situations? 3. help pupils in isolating the single major idea of a problem? 4. help pupils state problems as definite and concrete questions? 5. help pupils pick out and define the key words as a means of getting a better understanding of the problem? 6. help pupils evaluate problems in terms of personal and social needs? 7. help pupils to be aware of the exact meaning of word groups and shades of meaning of words in problems involving the expression of ideas? 8. present overview lessons to raise significant problems? 9. permit pupils to discuss possible problems for study? 10. encourage personal interviews about problems of individual interest? B. Collecting Evidence on Problems To what extent do you: 1. provide a wide variety of sources of information? 2. help pupils develop skill in using reference sources? 3. help pupils develop skill in note taking? 4. help pupils develop skill in using reading aids in books? 5. help pupils evaluate information pertinent to the problem? 6. provide laboratory demonstrations for collecting evidence on a problem? 7. provide controlled experiments for collecting evidence on a problem? 8. help pupils develop skill in interviewing to secure evidence on a problem? 9. provide for using community resources in securing evidence on a problem? 10. provide for using visual aids in securing evidence on a problem? 11. evaluate the pupils' ability for collecting evidence on a problem as carefully as you evaluate their knowledge of facts? C. Organizing Evidence on Problems To what extent do you : 1. help pupils develop skill in arranging data? 2. help pupils develop skill in making graphs of data? 30 3. help pupils make use of deductive reasoning- in areas best suited? 4. provide opportunities for pupils to make summaries of data? 5. help pupils distinguish relevant from irrelevant data? 6. provide opportunity for pupils to make outlines of data? 7. evaluate the pupils' ability to organize evidence on a problem as carefully as you evaluate their knowledge of facts? D. Interpreting Evidence on Problems To what extent do you: 1. help pupils select the important ideas related to the problem? 2. help pupils identify the different relationships which may exist between the important ideas? 3. help pupils see the consistencies and weaknesses in data? 4. help pupils state relationships as generalizations which may serve as hypotheses? 5. evaluate the pupils' ability to interpret evidence as carefully as you evaluate their knowledge of facts? E. Selecting and Testing Hypotheses To what extent do you: 1. help pupils judge the significance or pertinence of data for the immediate problem? 2. help pupils check hypotheses with recognized authorities? 3. help pupils make inferences from facts and observations? 4. help pupils devise controlled experiments suitable for testing hypotheses? 5. help pupils recognize and formulate assumptions basic to a given hypotheses? 6. help pupils recheck data for possible errors in interpretation? 7. evaluate the pupils' ability for selecting and testing hypotheses as carefully as you evaluate their knowledge of facts? F. Formulating Conclusions To what extent do you: 1. help pupils formulate conclusions on the basis of tested evidence? 2. help pupils evaluate their conclusions in the light of the assump- tions they set up for the problem? 3. help pupils apply their conclusions to new situations? 4. evaluate the pupils' ability to formulate conclusions as carefully as you evaluate their knowledge of facts?" Rewards of Quality Teaching. In studying the vast array of material which is being written about the teaching of science, one might conclude that it is impossible for an average person to direct effectively the science activities of secondary pupils for 180 days. Though the task is quite inclusive and though skill is needed to do the job, a person with a good background in the fields he is teaching, with a keen interest in boys and girls of high school age, with an understanding of the important goals in science education, and with an intense desire to do a good job, will find that science teaching can be challenging, fascinating. and successful. If one does not know exactly where to begin, he might start with this idea as expressed by Butler in the book. The Improvement of Teaching in the Secondary School, The 31 University of Chicago Press, Chicago, Illinois, 1954, p. 149 : "Pu- pils are stockholders in the learning enterprise. In one respect, that of possessing energy, they own all the stock. The teacher is a director. Unless energy is released, no learning can take place." Quality teaching in science every day in the year will bring satisfaction to teacher and pupils alike. Not only will pupils ac- quire valuable scientific information, but they will learn much about thorough, careful techniques of work. In addition, many of them will be so fascinated by science and by their progress in it that they will continue its study after high school days. Equally important is the fact that the scientific attitude toward all learn- ing and toward all life will become the possession of many pupils. What greater service can any teacher render? What greater re- ward can any teacher expect? 32 -" Hi CHAPTER 2— COURSES OF STUDY IN SCIENCE • Point of View Course of Study for Ninth Grade Science Man and His Physical World • Course of Study for Tenth Grade Biology Man and His Biological World • Course of Study for 11th and 12th Grade Chemistry • Course of Study for 11th and 12th Grade Physics New Approach to Physics 33 Courses of Study in Science POINT OF VIEW The various courses of study given on the following pages can do much to lift science instruction to a higher level; or they can prove to be as barren as a rock in the desert. The out- come will depend on how the material is used with high school students. Foremost in determining the manner in which the sugges- tions presented in this bulletin will be used is the philosophy of the teacher. No person can expect to raise boys and girls from one level of science learning to a higher plane of under- standing and appreciating science unless he has a clear picture of the road he wishes the boys and girls to travel and unless he has a knowledge of the field of study that will enable him to direct the learning experiences in the proper direction. A printed course of study cannot provide this vital part of instruction — it is a bare skelton which has no life. To translate the facts of science into a pulsating and vibrant curriculum, the teacher must add the life giving properties of body and feeling. The teacher's beliefs about the value of true scientific work, clearly organized in his mind, will give the energy and power to initiate this work. A quick survey of the four suggested courses of study in- cluded in this publication will reveal that they are organized on the unit-problem basis, consisting of basic concepts of science expressed in question form. Will the reading of one of the problems automatically assure that the student will accept this as an investigation on which he wishes to start work immedi- ately? All should agree the answer is "No." Problems are an individual matter. What is a problem to one student will be no problem to the student sitting in the next seat; he might know the answer already; he might not be stirred in the least by reading the question or by hearing it presented to the class. Thus the job of putting life into the problem becomes a major responsibility of the teacher. He must use all of his resources to stimulate his students to the point where they feel the prob- lem is something about which they wish to learn more, and which they wish to attack from several points of view. If this 34 degree of motivation is reached for many of the students in a class, the teacher can consider this phase of the work well done. To illustrate this point, a teacher might find that many of the students do not consider as real problems Newton's Three Laws of Motion, the laws of freely falling bodies, and terminal and escape velocity. But the scene might be changed by a brief, provocative discussion of the speed of 18,000 miles per hour that satellites must obtain if they are to stay in their orbits around the earth. The feeling that one would like to generate might be compared to that of a person waiting for a satellite to be fired. One can look out of the control tower and the "field is clear and motionless. Months and years of work rush to a climax just seconds away. The strange quiet is interrupted only by the regular booming of the loudspeaker. It calls out : 'Four, three, two, one . . . Fire!' A finger jabs a firing switch, and on a distant launching platform things begin to happen fast. From a needle-nosed cylinder seven stories high, power cords are ejected like great black snakes. Scalding steam bursts out in all directions, and a blinding blast of white-hot flame sears the ground. The thunderous roar is ear-splitting. At first slowly, then with gathering speed, 13 tons of burning gases force a huge rocket away from its launching stand. In seconds, it is a blazing streak far above the observers. Operation Vanguard has begun!"* A teacher does not have to be a dramatic actor in front of the class, but he does have to add life to the skeleton of a course of study. One might say the textbook will do this. Un- fortunately, courses built on textbooks alone will always be behind the times, for books cannot keep up with the swift march of science. For these courses to be kept up-to-date and to arouse the inquiring minds of students, they must include some of the wealth of materials which flow forth each day from newspapers, magazines, pamphlets, motion pictures, radio and television. But the inclusion of all these materials in the classroom will not assure that the course of study will emerge from lifelessness to life. The teacher must add the necessary ingredients of interpretation, probing questions and dissatis- faction with present knowledge of the topic under consideration. Some life can be added to the skeleton if high school science teachers will meet periodically with the 7th and 8th grade *The Story of IGY, Esso Standard Oil Co., New York. 35 science teachers and principals to discuss and plan the program for six years instead of following a common practice of every teacher doing what he thinks is best. Interest can be rapidly decreased by student reaction of the type: "We did the experi- ment on air pressure in the 7th grade; why do we have to do the same thing each year?" Needless and useless repetition can deaden a course in a matter of days. All should agree that no main scientific concept can be fully learned in the period of a clay, a week, a year, or probably twelve years, or a life- time. Recurring attacks on an important problem should be planned. Nevertheless, the approach must be different at differ- ent learning levels, and this problem can be partially solved by intergroup planning. For example, the 9th grade course of study is planned as "Man and His Physical World." This is not the typical General Science Course and so this change will affect the work clone in grades seven and eight. If the teachers in these three grades take a careful look at what the students should accomplish during the junior high school period, meaningful work can be developed which will keep alive the curiosity of the students. Even though this practice is followed, it must be realized that all students on a particular grade level will not read equally well, use numbers with equal facility, think equally well, write and speak with the same facility, or under- stand scientific concepts to the same degree. The course of study can cause a higher level of understand- ing on the part of the students if the many facts and ideas presented can be incorporated into larger scientific concepts, principles and generalizations. For example, the learning of the students in biology can result in only fragmentary ideas concerning energy and food. If students are given proper guid- ance and direction in their study, they should arrive at a major principle such as the following: "The energy which makes possible the activity of most living things comes at first from the sun and is secured by the organism through the oxidation of food within its body." Another example in the biological sciences is: "Carbon dioxide set free during the respiration of both plants and animals is absorbed by plants and used as a raw material of photosynthesis." The same condition holds true for the physical sciences. As a result of the work in chemistry over a period of time, a student might organize his learning into a principle stated in this manner: "Every pure 36 sample of any substance, whether simple or compound, under the same conditions will show the same physical properties and the same chemical behavior." This point of view has been expressed in a clear and con- cise manner by Curtis in the article, "Basic Principles of Science Teaching" published in The Science Teacher of March 1953. His fifth point in this discussion is : "The achieving of every objective of science must begin with the building of understandings." In this discussion, Curtis points out there are three levels of understanding: (1) the learning of facts, which is considered the lowest level; (2) understandings of scientific principles or generalizations by means of factual in- formation organized in meaningful ways; (3) synthesis of facts and principles into broad understandings. To illustrate this third level, Curtis gives examples such as the terms "sani- tation," "the living world." and "the atomic age." In this article, Curtis goes on to say : "A brief assaying of the functional potentialities of the three levels seems now in order ; facts are the fundamental and indispensable materials of all science training. This statement holds true whether the learner gains the facts through his own experimenting and observing, or learns them vicariously through reading. Yet, of the millions of available facts, only a relatively small per- centage are in themselves worth knowing for their potentially functional values. . . . "But granted that certain facts do possess potentially func- tional values, these values usually depend on the precise accu- racy with which they can be recalled. And it is distressingly true that the keen edge of factual knowledge quickly becomes chilled, if the facts are not frequently reviewed. Probably the most striking evidence of the ephemeral nature of purely factual information taught in science courses is provided by the find- ings of epoch-making studies by Tyler and others. The pooled results of these researches revealed that within a year after high-school pupils and college students had completed courses in science, they had forgotten as much as 77 percent of the facts that they knew upon completing those courses. The in- escapable conclusion from such findings would seem to be that a course that emphasizes the mere learning of scientific facts as an end in itself, is likely to prove subsequently to have been 37 almost a complete waste of teachers' and pupils' time and energy. "In contrast, however, with the rapid and extensive forgetting of facts is the high degree of retention of the ability to apply mastered scientific principles. The series of studies just cited produced substantial evidence supporting this statement. In the same period during which the subjects had forgotten most of the facts that they had learned in the various courses, they had suffered little or no loss of ability to apply principles. In fact, three years after the end of one course, the students had forgotten on the average about 72 percent of the factual in- formation, but they had gained 58 percent in their ability to apply principles. Perhaps the reason why the ability to apply scientific principles is retained is that, if a person thoroughly understands a scientific principle he is continually identifying situations in which he can apply it." One of the difficulties that every science teacher faces is how to cover all the material that is suggested in a course of study or all the material that is presented in a textbook. In many situations this cannot be done; nor is it necessary that this be attempted. What is far more important is that students have a good grasp of the material which is studied in a class. The press of time and the vast accumulation of scientific ma- terial should not cause one to hurry to the extent that a large number of the class have only a hazy idea of the concepts being studied. If a job is worth doing at all it is worth doing well. Other portions of this bulletin present techniques and ma- terials that might be used to make this skeleton into a subject which will become alive to the students. What is used will vary with each teacher because of differences in interests, abilities and training. The suggestions is made that all teachers survey their capacities and use their strengths at all times while cor- recting certain weaknesses that might be causing the course to be somewhat "dead." 38 COURSE OF STUDY FOR NINTH GRADE SCIENCE Man and His Physical World Unit One: What Does a Trip into the World of Atoms Reveal ? 1. What does a trip into history tell us about the changing ideas of matter? 2. What is our modern picture of atoms ? 3. What are the differences between chemical reactions and nuclear reactions ? 4. How does a knowledge of chemistry help in the work around the house ? 5. How does a knowledge of chemistry help the farmer in his work? 6. What industries in the community are dependent on some form of chemical change to make their products? 7. A brief look at the human body reveals what about its chemical composition and chemical changes? 8. What experimental work can be performed to explain some of the theories concerning matter? Unit Two: How is the Work of the World Done? 1 . How are energy, force and work related to each other ? 2. What is work and how is it measured ? 3. How are the various simple machines used to do work? 4. How has the life of man been affected by machines? 5. Why are petroleum, coal and water such important mate- rials to man? 6. How has man satisfied his need for more and more horse- power ? 7. How are electrons obtained to do work? 8. What is the relation between magnets, magnetism and electric motors? 9. How is electricity used to do the many jobs around the house? 10. What experimental work can be performed to clarify our thinking on energy, force and work ? 39 Unit Three: How Has Science Improved Communications in the Modern World? 1. What is sound and how do we hear it? 2. What is light and how is it changed into sight? 3. How are messages sent by wire and by wireless ? 4. How do we reproduce images and sound on film? 5. How does the radio work ? 6. What is television and how does it work? 7. What project or experimental work can be performed to clarify some of the scientific principles involved in com- munication ? 8. What does a field trip to the local telephone office, radio or TV station reveal about communications in your com- munity ? Unit Four: How Has the Face of the Land Changed over Vast Periods of Time? 1. What are some of the beliefs about the formation of the planet earth? 2. How were the mountains born and then worn away? 3. How has wind, water and ice changed the face of the earth ? 4. What stories do fossils tell us about our planets? 5. How are earthquakes and volcanoes changing the face of the land? 6. How does the force of gravity affect our planet? 7. How has the face of North Carolina changed over the eons of time ? 8. What are the major geological formations of North Caro- lina? 9. How have the soils of North Carolina been formed? 10. What are the important metals and non-metals found in the State ? 11. How can one identify some of the more common rocks and minerals found in the State ? 12. How have the various geologic resources affected indus- tries in the State? 13. How are the water resources interrelated to other renew- able resources in the State? 40 Unit Five : How Has Man Begun to Understand the Earth's Weather? 1. What has man learned about the make-up of the earth's canopy of air and its upkeep? 2. How does the heat of the sun and the spinning of the planet earth affect this ocean of air? 3. Under what conditions do atmospheric storms develop? 4. How are the changing conditions in the atmosphere meas- ured? 5. What do examinations of weather reports and visits to weather bureaus tell us about weather prediction? 6. What are the effects of climate upon plant life, animals, man and industry? 7. How does weather and climate vary in different sections of North Carolina? 8. What project or experimental work can be performed to clarify some of the scientific principles involved in the study of weather? Unit Six: What Does a Voyage into Space with the Astronomers Reveal? 1. What instruments has man developed to extend his vision into space? 2. What has been discovered about the place of the earth in its galaxy, the milky way? 3. How has man's ideas on the size of the universe changed? 4. How do the members of the solar system differ in appear- ance, structure and movement? 5. What causes night and day and seasons? 6. How are different positions on the earth's surface located? 7. By the use of appropriate star ,maps, what stars and con- stellations can be identified during the year ? Unit Seven : What Part Does Water Play in the Life of a Community? 1. What is the nature of water? 2. How do towns and cities obtain ample supplies of water ? 3. How is water made safe for use? 41 4. What are some of the impurities found in water and how are some removed ? 5. What have forests to do with water supply? 6. What is known about the ground water resources of North Carolina ? 7. What is known about the surface water resources in North Carolina ? 8. How do the various industries in North Carolina use water ? 9. How can the water resources of North Carolina be used to greater advantage? COURSE OF STUDY FOR TENTH GRADE BIOLOGY Man and His Biological World Unit One: What Is A Study of Life? A. What are the differences between living and non-living things ? B. What are the various specialized areas of biological work ? C. How does one carry on problem-solving in the life-sciences ? D. What is the nature of experimental work ? E. What materials and resources are available in the school to pursue the study of life and how can they best be used ? F. What does a brief survey of the immediate environment reveal about plant and animal life? G. How has man affected the environment? H. What are some major problems facing man that might be solved by more research in biological science or by better application of knowledge available? I. A field trip in the late afternoon or on weekends raised what important questions for future study? Reminder: A. Are students beginning to raise important questions ? B. What is the range in abilities, interests and achievement of the students. C. Is consideration being given to the use of student-assist- ants? Unit Two: How Are Living Things Alike? A. What are the building blocks of living things ? B. Examination of a number of prepared slides reveal what? C. How are slides of cells prepared? D. What is an atom, molecule and compound? E. What are isotopes and radioisotopes? F. Of what is protoplasm composed? G. What are tissues and organs? H. How do living things secure their energy? I. After observing one-celled plants and animals under the microscope and by careful observation of larger plants and animals, what life functions are carried on by all? 43 Reminder: A. Have all students become familiar with microscope or microprojector or both? B. Are students learning to do research work in the library? C. Have experiments been started which illustrate the use of controls ? D. Is careful consideration being given to the use of various techniques in the teaching process ? Unit Three: How Are Living Things Different? A. What kinds of plants are there ? 1. Seed Plants (a) What is the habitat of these plants ? (b) What is the structure of these plants? (c) What is the physiology of these plants? (d) Of what economic importance are they to man? (e) A survey of the local school community reveals what aboat their number and distribution? (1) Gymnosperms (2) Angiosperms — monocotyledons, dicotyledons 2. Ferns and Their Relatives (a) What is the habitat of these plants? (b) What is the structure of these plants? (c) What is the physiology of these plants? (d) Of what economic importance are they to man? (e) A survey of the local school community reveals what about their number and distribution? (1) Ferns (2) Horsetails (3) Club mosses 3. Mosses and Their Relatives (a) What is the habitat of these plants? (b) What is the structure of these plants? (c) What is the physiology of these plants? (d) Of what economic importance are they to man? (e) A survey of the local school community reveals what about their number and distribution? (1) Liverworts (2) Mosses 44 4. The Simplest Plants (a) What is the habitat of these plants? (b) What is the structure of these plants? (c) What is the physiology of these plants? (d) Of what economic importance are they to man? (d) A survey of the local school community reveals what about their number and distribution? (1) Algae (2) Fungi B. What kinds of animals are there? 1. Animals with Backbones (a) Where do they live? (b) How do they live? (c) A survey of the local school community reveals what about their number and distribution? (d) Of what economic importance are they to man? (1) Mammals (2) Birds (3) Reptiles (4) Amphibians (5) Fish 2. Animals Without Backbones (a) Where do they live? (b) How do they live? (c) A survey of the local school community reveals what about their number and distribution? (d) Of what economic importance are they to man? (1) Insects and their relatives (2) Spiny-skinned animals (3) Soft-bodied animals (4) Worms (5) Jellyfish (6) Sponges (7) Protozoa Reminder: A. Have those students with a keen interest in collecting and classification been encouraged to go much farther with the work than the class as a whole ? B. Have a number of the students decided to carry on a sim- ple research project? 45 C. Are the rapid learners as well as the average and slow groups being encouraged to work at their level of ability? Unit Four: How Do Living Things Maintain Themselves? A. How Do Higher Plants Live and Reproduce? 1. What is the general structure of a seed plant — the roots, stems and leaves? 2. What is meant by the term osmosis? 3. How do green plants manufacture food? 4. What are sugars, starches, fats and oils, proteins? 5. What are the amino acids? 6. How is respiration carried on in a seed plant? 7. How is nutrition carried on in a seed plant? 8. How is excretion carried on in a seed plant ? 9. How is motion carried on in a seed plant? 10. How is circulation carried on in a seed plant? 11. How are seeds formed in seed plants? B. How Do Higher Animals Live and Reproduce? 1. How is respiration carried on in higher animals — the earthworm, frog, man? 2. How is nutrition carried on in higher animals — the earthworm, frog, man? 3. How is excretion carried on in higher animals — earth- worm, frog, man? 4. How is motion carried on in higher animals — earth- worm, frog, man? 5. How is circulation carried on in higher animals — the earthworm, frog, man? 6. How is reproduction carried on in higher animals — earthworm, frog, man? 7. What are enzymes and hormones? Reminder: A. Are students beginning to base opinions and conclusions on adequate evidence? B. Are field trips being used to gather data and to arouse questions by students? C. What strengths and weaknesses of the students are being discovered as the result of observation and testing? Unit Five: How Do Living Things Behave? A. What is meant by stimulus and response? 46 B. What is meant by irritability of protoplasm? C. What is the relation between hormones and tropisms in plants ? D. What two types of muscles respond to stimuli? E. What are nerve cells? F. What is meant by a nerve impulse? G. What are reflex arcs in a nervous system? H. What are the parts of the human brain and how do they function ? I. What are the sense organs in man and how do they func- tion ? J. What is meant by behavior? K. What are conditioned reactions? L. What is learning? M. What is problem-solving? N. What is the relation between education and behavior in man? O. What effect do some chemical compounds have on behavior ? Reminder: A. Is growth in emotional maturity among the students de- tected ? B. Are there problem cases, for example among the repeaters, on which further guidance is needed? C. Have experiments been performed to show the effect of plant hormones? D. Is the quality of student experiments and projects im- proving ? Unit Six: How Does Life Continue From Age To Age? A. Plants and Animals of the Past 1. What are some of the theories about the formation of the earth? 2. How have the most recent estimates of the age of the earth been determined ? 3. What plants and animals were dominant in the last three big divisions of the earth's history (eras) ? 4. What do fossils show about the history of living things ? 5. What is meant by the theory of natural selection? 6. What is meant by variation, adaptation, survival of the fittest, artificial selection, the theory of mutation? 47 7. What was early man like ? 8. What are the main races of man today ? B. The Inheritance of Traits 1. What were some of Mendel's findings? 2. What is meant by his principle of dominance and prin- cipal of segregation? 3. What is meant by the principle of recombination? 4. What is the explanation of the 1:2:1 ratio? 5. What are genes and how do they work? 6. What are chromosomes? 7. What is a mutant and what are some causes of muta- tion ? 8. What is meant by the term hybrid? 9. What are some principles of human genetics ? 10. What are some defects that run in families? 11. How has a knowledge of the principles of genetics helped in the development of improved plants and ani- mals? C. Reproduction in Plants and Animals 1. How do one-celled organisms reproduce? 2. What is meant by asexual reproduction? 3. What is meant by sexual reproduction? 4. How do higher plants reproduce? 5. What are the following plant organs: sepals, petals, stamens, pistils, filament, anther, stigma, style, ovary, ovules ? 6. What is meant by pollination? Cross-pollination? 7. What are the parts of the bean seed ? 8. How are seed scattered? 9. How do various vertebrates reproduce? 10. How do mammals reproduce? 11. What is meant by the Rh factor? 12. How does a cell divide ? 13. Where does mitosis occur? 14. What is meant by chromosome number? 15. What determines the sex of offspring? 16. What is meant by cell differentiation? Reminder: A. Have plans been made to have the class or several mem- bers of the class visit the N. C. State Museum in Raleigh ? 48 B. Are motion picture films being used to supplement the in- structional program? C. Are the students curious about the "whys", "whats" and "hows" of observed phenomena? Unit Seven: How Does The Human Body Maintain And Protect Itself? A. How Does the Body Use Food and Oxygen ? 1. How is food digested in the mouth, stomach and in- testine? 2. What are the various digestive glands and the enzymes they produce ? 3. How do digested foods enter the bloodstream? 4. How does oxygen enter the bloodstream? 5. How does the blood circulate in the body? 6. How does food and oxygen get to the individual cells? 7. How are the wastes excreted from the body? 8. What do carbohydrates, fats and proteins furnish to the body ? 9. How is the energy of foods measured? 10. Why are vitamins important? 11. How does cooking affect vitamins? 12. What should one eat? 13. What are the internal regulators of the body? 14. Of what is the blood composed? B. How Does the Body Fight Off Diseases? 1. During the past centuries what did people think caused diseases ? 2. What are bacteria? 3. How do bacteria cause disease? 4. What diseases are caused by organisms other than bac- teria ? 5. What are allergies? 6. How was smallpox conquered? 7. What are the types of immunity? 8. How have methods of diagnosis improved? 9. What is cancer and what can be done to control it ? 10. How can heart disease be controlled? 11. What is meant by "preventive medicine"? 49 Reminder: A. Has a doctor in the community been asked to discuss with the students some of the recent advances in medicine? B. Has an effort been made to secure a qualified person, if you feel you are not, to discuss with the boys and girls their sexual growth and its effect on their physical and emotional life? C. Have some of the students prepared cultures of non- pathogenic bacteria? D. Are plans being made to inventory the science department and to prepare orders for supplies and equipment for next year? Unit Eight: How Do Living Things Affect The Welfare Of Man ? A. How have rocks been changed to soil? B. What is meant by top-soil, sub-soil, bed-rock? C. What element are there in the soil that plants need and what effect do these elements have on the growth of plants ? D. What is meant by: the nitrogen cycle; carbon cycle; oxygen-hydrogen cycle? E. How is the top-soil being eroded away? F. How can erosion be checked? G. What is meant by "The falling water table"? H. What farming methods help conserve water? I. How do forests affect the water supply? J. What are the important enemies of forests? K. What can be done and is being done to speed up refores- tation ? L. What relation is there between forests and wild life ? M. How can a proper balance of wild life be maintained? N. What is meant by the term "biome" ("major biotic com- munity") ? 0. What is meant by the term "ecology" ? P. What is meant by the term "natural succession"? Q. What types of conservation are being practiced in the community ? R. What responsibilities does each individual have in this matter? 50 S. What county, state and national agencies can give assist- ance in conservation ? Reminder: A. What projects have individuals and small groups of the class done to promote better conservation practices? B. What do tests and observations show about the achieve- ment of the pupils and their growth in problem-solving? C. Can you detect better health practices among the students as a result of the biology work? D. Will some of the students carry on simple research proj- ects during the summer? COURSE OF STUDY FOR ELEVENTH AND TWELFTH GRADE CHEMISTRY Unit One: What Are The Properties of Matter? A. Historical Development 1. What was the belief of the ancient Greeks and the al- chemists concerning the make-up of matter? 2. Why was the overthrow of the Phlogiston theory an im- portant step in the advance of chemistry? 3. Why are all materials now classified as elements, com- pounds or mixtures? 4. What picture of the atom can be given from the informa- tion now available? 5. What are some good comparisons to use to show the size of atoms and molecules? B. Kinds of Changes of Matter 1. In what ways can the physical properties of matter be altered ? 2. What are the characteristics of chemical change? 3. Are there exceptions to the Law of Conservation of Matter? 4. How are the facts of a chemical reaction expressed? 5. How is energy related to physical and chemical change? 6. What chemical changes are involved in the preparation, study and use of oxygen and hydrogen? 7. How can the lattice of a solid be broken? 8. What are the properties of a liquid that enable a solu- tion to be made? 9. Why are solutions important? 10. What are the main points of the kinetic-molecular theory? C. Measurement of Matter and Changes 1. How are length, area, volume, weight and density meas- ured in scientific work? 2. What are some of the effects of temperature on solids, liquids, and gases? 3. What are the various scales for measuring temperature? 4. How is heat measured? 5. How is air pressure measured? 6. How can problems dealing with changes in tempera- ture, pressure and volume of gases be solved? 52 Unit Two: What Is The Structure Of Matter? A. Units of Matter 1. How does the electrolysis of water, the Law of Definite Composition, and the Law of Multiple Proportion show that atoms exist? 2. How has Gay-Lussac's Law of Combining Volumes and Avogadro's Law enabled chemists to determine molecular weights ? 3. What is meant by a "mole" of a substance? 4. How is the density of a gas used to determine its mole- cular weight? 5. How can the lowering of the freezing point or raising of the boiling point of a solution be used to determine molecular weights? 6. How are atomic weights determined by analyzing moles of various gases? 7. How are equivalent weights used to determine atomic weights ? 8. How are formulas determined by the use of atomic weight and the percentage composition. B. Electrical Nature of Matter 1. What are the electrical particles that make up the atom? 2. How are the electrons arranged in various types of atoms? 3. How are some chemical combinations explained by the electron theory? 4. What is meant by combining number or valence? 5. How does a knowledge of valence aid in writing formulas? C. Classification of Elements 1. How did Mendelejeff classify the elements? 2. How is the Periodic chart helpful to chemists? 3. Why are modern classifications based on atomic number rather than atomic weight? D. Reaction of Elements to Form Compounds 1. What are ionic compounds, co-valent compounds, radicals? 2. What are polar molecules? 3. Why are some molecules nonpolar? 4. What does a complete chemical equation mean? 5. How are the following chemical problems solved : weight- weight? weight-volume? volume-volume? 53 E. Reactions Within the Nucleus 1. What is an atomic pile? 2. What are nuclear reactions? 3. What happens when atoms undergo fission or fusion? 4. Why are enormous quantities of energy released in nu- clear reactions? 5. What is a "breeder" reactor? 6. What are isotopes? 7. How are "tracer" elements used in research? Unit Three: What Changes Occur In Solutions? A. Water — The "Universal Solvent" 1. By analysis and synthesis the composition of water has been determined as what? 2. What makes water the most important mineral of all? 3. What are the important physical properties of water? B. Forming of Solutions 1. What is meant by the term solute? solvent? 2. What determines the amount of solute that will dissolve? 3. What is meant by a saturated solution? A supersaturated solution ? 4. When does crystallization occur? 5. How are solution concentrations expressed? D. Colloidal State 1. What are the types of colloidal dispersions? 2. What are the characteristic properties of matter in the colloidal state? 3. How can colloids be prepared? 4. Why is the colloidal state so vital? E. Ions and Dissociation 1. How did Arrhenius explain : the conductivity of solu- tions? the action of acids? the action of bases? neutrali- zation 9 abnormal boiling and freezing points of solutions? 2. How was the theory of Arrhenius later modified? 3. How do ions in solution react? 4. How is electric current used to promote chemical change ? 5. How is chemical change used to generate current? 6. How does one know when he has an acid? 7. What are the common acids and how are they prepared? 8. How does one know when he has a base? 54 9. What are the common bases and how are they prepared? 10. What is the scale of acid-base values? 11. How are the important acids and bases used? 12. How are salts produced by neutralization? 13. How are salts named? Unit Four: How Do Chemical Families Vary In Their Properties ? A. The Acid Forming Elements 1. How do the four members of the halogen family com- pare in atomic structure? 2. How are the members of the halogen family prepared? 3. What is meant when it is said that many halogen re- actions are oxidation-reduction reactions? 4. What are the important uses of these four elements? 5. How do the members of the sulfur family compare? 6. How are the important compounds of sulfur used? 7. What are the relations among members of the nitrogen family ? 8. Why is nitrogen an important element? 9. How is ammonia prepared and used? 10. How is nitric acid prepared and used? 11. How are explosives made and used? 12. Of what value are arsenic antimony, bismuth and phos- phorus? B. The Base Forming Elements 1. How do the sodium family elements compare? 2. How are the members of the sodium family prepared and used? 3. What does a study of the atomic structure of the ele- ments of the calcium family reveal about their properties? 4. How are calcium and its relatives prepared and used? 5. What is the chemistry of the amphoteric, rare-earth and inert elements? 6. How are the derivatives of silicon prepared and used? Unit Five: What Does The Realm of Carbon Comprise? A. The Simpler Compounds of Carbon 1. In what three forms does carbon occur and what are some of the main uses? 55 2. What is meant by the carbon dioxide-oxygen cycle? 3. What are the chemical properties of carbon dioxide? 4. The main uses of carbon dioxide are what ? 5. What are the chemical properties of carbon monoxide? 6. What are some of the more important gaseous fuels? B. The Hydrocarbons 1. What is the methane or paraffin series of hydrocarbon compounds? 2. Why is the methane series called a saturated-chain series of hydrocarbons? 3. What are examples of unsaturated-chain hydrocarbons and their derivatives? 4. What are the unsaturated "ring" hydrocarbons? 5. By what processes are derivatives of hydrocarbons made? 6. In what manner are alcohols formed as derivatives of hydrocarbons? 7. If two or more alcohols have the same molecular formula, what are they called? 8. What are some of the many and varied products of alcohols? 9. From the reaction of alcohols with acids, what products are formed? 10. What is a "soapless" soap? C. Petroleum Products 1. Where are petroleum deposits found? 2. Of what is petroleum composed? 3. What products are obtained by the refining of petroleum? 4. Why is the "cracking" process used? 5. What other processes are used to produce gasoline? 6. What effect does the addition of tetraethyl lead to gaso- line produce? 7. What is meant by the "octane rating" of gasoline? D. Foods and Chemotherapy 1. What are the substances found in foods that are necessary for good health? 2. What are different kinds of carbohydrates? 3. How is glucose made by the process of photosynthesis? 4. What is the chemical composition of fats? 5. What is the chemical composition of proteins? 6. What are vitamins and what do they do? 56 7. What is a balanced diet? 8. What substances retard the growth of or destroy bacteria ? 9. What are some of the substances used to deaden pain? 10. What are laxatives, cathartics and purgatives? E. Organic Materials in Chemical Manufacture 1. What is cellulose? 2. How is cellulose changed into paper? 3. What kinds of molecules make a textile fiber? 4. How is rayon made by the viscose process? 5. How was nylon fiber synthesized? 6. What are some of the dyes obtained from coal tar? 7. What kinds of plastics are made today? 8. How is synthetic rubber produced? Unit Six: How Are Metals Obtained And Used? 1. What are the physical properties of metals? 2. What are the chemical properties of metals? 3. What are the general methods of extracting metals from ores ? 4. What "accident of nature" has enabled the United States to develop a huge steel industry? 5. What chemical reactions take place in the metallurgy of iron ? 6. What is a blast furnace and how does it work? 7. By what three processes is steel made? 8. What are some compounds of iron of interest and im- portance to man? 9. How are the "heavy metals" (copper, silver, mercury and gold) secured and used? 10. How are the light metals (aluminum, magnesium, titan- ium and beryllium) prepared and used? 11. Why have metallurgists developed alloys? 12. How are metals guarded against corrosion? Unit Seven: How Does The Chemist Help The Farmer? 1. What are soils? 2. What are the main types of soils in North Carolina? 3. How is soil acidity measured and how can the acidity be changed? 4. What makes a fertile soil? 57 5. What elements do growing plants take out of the soil? 6. How is nitrogen provided for the soil? 7. How is phosphorus provided for the soil? 8. How is potassium provided for the soil? 9. What are the "trace elements" ? 10. What is a "complete" commercial fertilizer? 11. What happens when plants have a deficiency of certain minerals? 12. How can plants be grown without soil? 13. What chemical compounds are used to control plant pests? 14. What fungicides and antibiotics are used to control plant diseases? 15. How are weeds being controlled and destroyed? COURSE OF STUDY FOR ELEVENTH AND TWELFTH GRADE PHYSICS Unit One: Matter, Energy, Work, Power, Machines — An overview of Physics — Why? A. A Quantitative Science 1. How does matter differ from energy? 2. How do the different forms of energy provide the basis for the work in physics? 3. What is meant by the law which might be called the Law of Conservation of Matter-Energy? 4. What are the fundamental units used to measure length, mass and time? 5. What is the difference in mass and weight and how are they measured? 6. What is density and how is it measured? 7. What is specific gravity and how is it measured? B. Work and Energy 1. How T was work done in early times by man? 2. As the term "work" is used in mechanics, what meaning does it have? 3. How is work measured and in what units can it be ex- pressed ? 4. The capacity of a body or system of bodies for doing work is expressed in what manner? 5. What is power and in what units can it be expressed? 6. What does a machine do? 7. How does friction affect work? 8. What is efficiency and how is it measured? 9. What is meant by the term "mechanical advantage" as applied to a machine. 10. How are efficiency and mechanical advantage computed for the lever, wheel and axle, pulley, inclined plane, wedge and screw? 11. How may simple machines be combined to form com- plex ones? 12. As an example of a combination of two simple machines, how does a micrometer work? 13. How are the gears in the transmission of an automobile arranged for the car to operate at highest efficiency? 59 14. How is motion changed in the differential of a car? 15. How do "automatic" transmissions differ from regular transmissions? C. Forces and Motion 1. How are parallel forces related? 2. What is the effect of several forces acting at one point? 3. How may a single force produce other forces? 4. What are some applications of forces in balance? 5. What is meant by the center of gravity? 6. What is meant by stable equilibrium? unstable equili- brium? 7. How does speed differ from velocity? 8. What is momentum and how is it measured? 9. What is Newton's First Law of Motion and what does it mean? 10. What is acceleration and how is it produced? 11. What is uniform motion? 12. What mathematical relationship gives Newton's Second Law of Motion? 13. What is the Third Law of Motion and what does it mean? 14. What are centripetal and centrifugal forces and how are problems involving the two forces solved? 15. What is Newton's law of universal gravitation? 16. How can weight and mass be distinguished more clearly? 17. How fast do freely falling bodies fall? 18. What are the mathematical relationships which express the so-called laws of freely falling bodies? 19. How are problems dealing with vertical upward motion and horizontal motion solved? 20. What are terminal velocity and escape velocity? 21. How is the period of a pendulum determined? D. Forces in Fluids 1. What is pressure? 2. Pressure at a given depth in a liquid depends upon what two quantities? 3. How do standpipes in water systems make use of pres- sure? 4. What is Pascal's Law? 5. How is Pascal's Law applied? 6. What is buoyancy and how is it calculated? 60 7. Why does an object sink or float? 8. What is a hydrometer? 9. What are some important applications of Archimedes' Principle? E. Forces in Gases 1. To what is the force of air clue? 2. How is air pressure measured? 3. What is an atmosphere? 4. Why does a balloon float in air? 5. What enables an airplane to rise in the air? 6. What is Bernoulli's Principle? 7. What is Boyle's Law? 8. How does a siphon work? 9. How do lift and force pumps work? 10. How is air pressure used in predicting weather. Unit Two: How Are Heat and the Motion of Molecules Related ? A. Molecular Structure of Matter 1. What is an atom? 2. What is a molecule? 3. What is the kinetic-molecular theory of matter? 4. What is meant by the Brownian Movement? 5. How does the motion of molecules explain: evaporation? sublimation? diffusion? 6. What holds molecules together? 7. Why does the surface film of a liquid have an elastic force ? 8. Why are soap bubbles round? 9. Why do liquids cling to solids? 10. How does action of molecules explain absorption and adsorption? 11. What are some illustrations that show the size of mole- cules and their speed? B. Heat and Expansion 1. What is the nature of heat? 2. How is temperature measured? 3. How can one temperature scale be changed into another? 4. What is absolute zero? 61 5. How is the coefficient of linear expansion determined in the laboratory? 6. What are some facts about the expansion of liquids and gases when heated? 7. What is Charles' Law? 8. What is the general gas law? C. Measuring Heat 1. What are the units of heat energy? 3. What is specific heat and how are calculations made when using it? 3. What is involved when ice changes to water? 4. What is unusual about the action of water when freezing? 5. What effect does pressure have on the melting point of ice? 6. How can the freezing point of water be lowered? 7. What is heat of vaporization of water? 8. How is the boiling point of a liquid affected by pressure? 9. On what principle does the pressure cooker work? 10. What is relative humidity and how is it determined? 11. How is dew point measured? 12. What are some of the most important condensations in the atmosphere? 13. How does evaporation produce cooling? 14. What is the principle of a mechanical refrigerator? D. Transference of Heat 1. What is convection? 2. What is conduction? 3. What is radiation? 4. What are the laws of radiation? 5. How are convection, conduction and radiation used? 6. What are good absorbers and radiators of heat? 7. How does the sun provide the earth with heat and light? E. Work and Heat 1. How did Joule determine the relation between heat and work? 2. What is heat of combustion? 3. How is the energy content of foods expressed? 4. How are heat engines classified? 5. How does the modern steam engine operate? 6. How does the steam turbine operate? 62 7. How does the gasoline engine operate? 8. How does the diesel engine operate? 9. How does the jet engine operate? 10. What is the power for rockets? 11. What is horsepower and how is it calculated? Unit Three: How is Sound a Motion of Vibrations? 1. What starts a sound? 2. What occurs in a medium when sound travels through it? 3. What are wave length, amplitude and frequency? 4. How fast does sound travel? 5. What factors determine the intensity of sound? 6. What are the relationships among wave length, frequency and velocity? 7. What is resonance? 8. What causes wave interference? 9. When is sound a noise? 10. How is the intensity of sound measured? 11. How are rooms treated to make for better listening con- ditions? 12. How do stringed instruments work? 13. How do other musical instruments work? 14. How does man hear? 15. How may sounds be reproduced? 16. What determines the quality of a musical sound? 17. What is the scientific basis of the musical scales? Unit Four: How Has Electricity Become the Powerful Servant of Man? A. Static Electricity 1. How is static electricity produced? 2. Why do some charged bodies attract and others repel? 3. What is Coulomb's Law? 4. How can electrical charges be detected? 5. How may electrostatics be explained by the electron theory ? 6. Of what do atoms consist and how are the parts arranged ? 7. How are the electrons arranged in the atom? 8. How are the chemical properties of atoms explained by the electron theory? 63 9. What is meant by atomic number? 10. Why is current believed to consist of moving electrons? 11. How is electrical potential developed? 12. What are the units of electrostatic electricity? 13. How does the electron theory explain Leyden Jars, con- densers and lightning? B. Producing Electric Current by Chemicals 1. What important contributions did Volta and Galvani make? 2. How does a Voltaic cell operate? 3. How do other simple cells work? 4. What chemical changes does an electric current produce? 5. How does a storage battery work? C. Magnetism 1. What common materials are magnetic? 2. What is the nature of magnetism? 3. What is the relation between electricity and magnetism? 4. What are some of the uses of electromagnets? 5. How does the earth act as a magnet? D. Measuring Electricity 1. What are the seven important electrical units of measure- ment? 2. How are the various meters used to measure current, voltage, and resistance in a circuit? 3. What is Ohm's Law? 4. What are the laws governing series circuits? 5. What are the laws governing parallel circuits? 6. Upon what factors does the resistance of a wire depend? 7. When should cells be connected in series? 8. How is electrical power determined? 9. How is electrical energy measured? 10. How does a fuse serve as an electrical safety valve? E. Generating Current 1. What is an induced current? 2. What applications have been made of induced currents? 3. How do electromagnetic induction coils operate? 4. Does one get something for nothing from a transformer? 5. How are transformers used in the transmission of elec- trical power? 6. What are the properties of an alternating current circuit? 7. How can alternating current be changed to direct current ? 64 F. Electricity and Communication 1. How is sound changed into electricity? 2. How are radio waves generated and transmitted? 3. How is the carrier current modulated? 4. What are the meanings of cycle, frequency and wave length ? 5. How does the crystal detector work? 6. What are the components of a radio receiver? 7. What are transistors? 8. How does frequency modulation reduce static? 9. How does modern television transmission work? 10. How do modern television receivers work? 11. How is color television achieved? 12. What are the basic principles of radar? 13. How are sound motion pictures produced? Unit Five: How Is The Riddle of Light Being Gradually Solved? A. Nature of Light 1. How have earlier theories of the nature of light contri- buted to our knowledge of light? 2. Under what conditions does light behave like waves? 3. Under what conditions does light behave like a stream of particles? 4. Why is light a form of energy? 5. How has the speed of light been determined? B. Control of Light Energy 1. How is light energy controlled by reflection? 2. What mathematical relationships enable one to better understand reflection ? 3. How are light rays bent in passing from one medium to another? 4. How can index of refraction be determined? 5. How do lenses refract light? , 6. What is the lens equation? C. Optical Instruments and the Eye 1. How is the eye constructed? 2. How does the eye accommodate for distance? 3. What are some common defects of seeing and how are lenses used to correct these defects? 4. How does the camera compare with the eye? 65 5. How is the amount of light reaching the film controlled? 6. What is the structure of the photographic enlarger? 7. How are objects magnified in a compound microscope? 8. What are the differences between reflecting and refract- ing telescopes? 9. Upon what principle does the electron microscope operate? D. Illumination 1. How is quantity of light measured? 2. How is quality of light determined? 3. How can illumination be fitted to the job? E. Color and Spectra 1. How do wave length and frequency determine what a color is to be? 2. What is an Angstrom unit? 3. How do eyes function in seeing color? 4. What causes a rainbow? 5. What are primary colors? 6. What are complementary colors? 7. What happens w T hen color pigments are mixed? 8. What happens when white light is passed through glass of different colors? 9. What happens when the dispersed light of the spectrum formed by a prism falls upon colored opaque objects? 10. How is color used in the study of the nature of matter? Unit Six: How Is Energy Obtained From The Nucleus of an Atom? 1. What is the nature of the radiations from radium and other radio-active materials? 2. How can radiation be detected? 3. What are the products of the disintegration of radium atoms ? 4. How does the energy produced in the sun support Ein- stein's theory about the equivalence jf mass and energy? 5. How is Einstein's theory confirmed when lithium is bombarded by protons in a cyclotron? 6. What evidence is there which shows how neutrons and protons might be held together in the nucleus? 7. What happens when an atom of uranium-235 is hit by a proton to cause a chain reaction? 66 8. How does a nuclear reactor produce a controlled chain reaction ? 9. Why is the determination of "critical mass" of uranium- 235 basic in producing an atomic explosion? 10. How is plutonium produced? 11. How does nuclear fusion differ from nuclear fission? 12. How are radioactive isotopes produced? 13. How are radioactive isotopes used in research? 14. How can nuclear reactors be designed to produce elec- tricity and to furnish power for ships? 15. As a result of information obtained about the atoms how can the age of the earth be calculated? 16. How is the nuclear reactor at N. C. State College, Raleigh, being used to advance the knowledge of the atom? NEW APPROACH TO PHYSICS The preceding suggested course of study for Physics can be classified as the "typical" or "traditional" course in high school physics. This is the type of program which has been offered to the high school student for many years. New discoveries have been added, such as the discussion on nuclear energy, but the basic organization is about the same as it has been for the past generation. Even though new material has been added, very little has been deleted, giving a huge mass of material to be covered. A number of scientists and educators feel that this kind of course does not provide the type of experience that will be needed in the latter part of the 20th century. Because of this belief, a Physical Science Study Committee, with headquarters at the Massachusetts Institute of Technology, was organized to study this problem and to bring out specific recommendations. The re- sults to date of the work of this distinguished group give a pic- ture of possible revolutionary advancement in the teaching of secondary school physics. In order for all the high schools of this State to have a preview of this suggested major change in the physics program, the fol- lowing article is presented with the hope that a careful study will be made of the ideas and that many teachers will be inspired and motivated to rethink the teaching of physics. Also, an out- come sought by this presentation is carefully planned experi- mentation by some schools to determine the effectiveness of this program or others that may be developed. 67 A BLUEPRINT * The general report of the Physical Science Study Committee includes the following statement of specific aims: "(1) To plan a course of study in which major developments of physics, up to the present time, are presented in a logical and integrated whole: (2) to present physics as an intellectual and cultural pursuit which is part of present-day human activity and achieve- ment; and (3) to assist physics teachers, by means of various teaching aids, to carry out the proposed program." The course of study now being prepared by PSSC embodies these aspirations. The PSSC course begins with a general introduction to the fundamental physical notions of time, space, and matter: how we grasp and how we measure them. As the student learns of the almost boundless range of dimension from the immensely large to the infinitesimally small, from microseconds to billions of years, he also finds out how these magnitudes can be measured and that instrumentation is simply an extension of his senses. We can thus teach measurement in order to answer real ques- tions raised while we present the relative sizes of atoms, us, our world, the solar system, and the galaxy by more than mere as- sertion. This introduction anticipates qualitatively most of the rest of the course. The student should be led imperceptibly to realize that physics is a single subject of study — time, space, and matter cannot be separated — that it is a developing subject, and that this development does not take place outside our own intimate world. It is the imaginative work of men and women from whom the student does not noticeably differ. From this introduction, the student should emerge with a sense of the high adventure of physics and with some of the equip- ment he must have if he is to participate in that adventure, either through his career or as an intelligent citizen in a science- minded world. After looking at the broad picture, we start to examine it in more detail. Here we begin with light. There are many reasons for this choice rather than the more usual choice of mechanics. Light is a concept with which the student is imme- diately and convincingly familiar. He has seen rainbows, oil slicks, lenses, and the bent stick in the pond; he is prepared to accept light phenomena as something well within his ordinary experience. We live by light. The study of the manner in which light behaves can proceed by easy steps and can be supported by laboratory work that is at once simple and rigorous. It draws on the simplest of mathematics ; simple geometric diagrams. As it led historically, the natural development of the subject leads us first to explore certain laws such as SnelPs law (the sec- ond law of refraction) , and then to the development of a particle theory of light, which attempts to put an explanatory picture behind those laws. We distinguish broad physical theory from *Prancis L. Friedman, Associate Professor of Physics, Massachusetts Institute of Technology. — The Science Teacher, November, 1957. 68 narrow physical law. Through careful investigation of light, the discussion illustrates the manner in which virtually all scientific knowledge develops. Under our continued scrutiny, the simple particle picture proves inadequate, and the student is led to con- cede that before we can proceed usefully with the study of light, we need to understand wave phenomena. It is not a question of presenting waves as complex dynamical systems. The student observes the behavior of ropes and ripples. Studying this behavior, particularly under controlled conditions in the ripple tank, he learns to recognize a group of characteris- tics that constitute wave behavior. We then find these same char- acteristics in the behavior of light. Thus, at the end of this por- tion of the course, the earlier problems concerning the nature of light are resolved. At this point, as at others, we notice the new questions that inevitably arise from what we learn ; what is the medium for light that acts like water for ripples ? We raise such problems to show the open-ended nature of physical thought. During this portion of the course, which occupies approximate- ly the first half year, dynamical considerations are subordinated. At most dynamics is treated descriptively. The principal em- phasis is on the kinematics of our world : where things are, how big, and how they move, not why. The second half of the course now embarks on a study of dynamics. Newton's laws connect motions with forces. Not only can they be used to predict motions when forces are known, but they can inform us about forces when motions are observed. Thus we tell the extraordinary story of the discovery of universal gravitation. We also introduce the conservation laws, and they form a substantial portion of this section of the course. We stress their wide applicability and their use in situations where detail is inaccessible, such as cosmic ray collisions and the kinetic theory of gases. Again in this part of the course, we go over ground viewed earlier, and the student will discover that he can read new sig- nificance into familiar material. Once again he will be impressed with the cyclical nature of the study of physics and with the constant refining process to which we subject physical knowledge. In the introductory section of the whole course, and again in the kinetic theory, we deal with submicroscopic particles. We now treat electricity as one of the fundamental characteristics of these particles. Currents, moving charges and magnets are stud- ied. Through the induction laws we arrive at the possibility of electromagnetic waves — a subject we can only sketch. The ex- perimental facts, however, clearly tie the electric phenomena to the electromagnetic spectrum. Another great circle is closed, binding dynamics, electricity, optics, and waves in a single em- bracing picture. The apparent completeness of this picture is denied by the photoelectric effect, but a more complete picture emerges before the end of the course. Through the discrete interactions of light with matter, we see photons; and through the photons and the 69 experiments of Franck and Hertz on excitation, we see energy states in atoms. Our job is to describe both the wave patterns and the individual events that resemble the action of particles. This is nature and not, as is often said, a "contradiction." In- stead of fighting straw men, we put the emphasis on describing nature. As de Broglie pointed out, the existence of wave-like and particle-like aspects of light suggest that there may be wave- like aspects of the behavior of matter. We can now show the wave nature through the same wave properties we found many times in our earlier wave discussion. The standing matter waves finally give the explanation of the energy states. Let us look back for a moment and see how the wave concept, for example, pervades the course, and is used to deepen the stu- dent's understanding of science. In the introduction to the course, the identifying colors of characteristic spectra are used simply as evidence of the existence of elements and atoms. Next, in the study of waves, we identify spectral color with frequency. Then in mechanics and electricity, when we lay the basis of the Ruth- erford model, the introduction of photons changes frequency to energy. This permits us to associate spectra with the atom as a picture of its energy states ; and the Bohr model results. Matter waves then finish the picture. The concepts of energy states and wave phenomena then carry us into the new realm of nuclear physics, where we are also able to examine the outstanding evi- dence that E = mc 2 , and to understand the basis of nuclear fis- sion and fusion. In this course the logical unity of the subject is apparent. This integration of knowledge makes it possible for understanding to aid memory far more than usual. In addition, the integration of ideas gives the student the sense of a continuing development which in itself is intellectually exciting. The repeated appearance of certain concepts, such as submicroscopic particles, is essential. So also is the patient and detailed treatment of certain subjects. We explore parts of optics, mechanics, and atomic physics more deeply than usual in order to show how we develop a field of thought. The price is subordination and even omission of many subjects commonly covered in high school courses. Heat and sound are not treated as independent subjects, but more nearly as examples: sound as an example of waves, heat as related to kinetic theory and to the conservation of energy. Hydrostatics and hydrodynamics are out. Technological applications are cut far back at all points. Such radical omissions are necessary. In fact, the committee's deliberations began with pleas from science teachers to reduce substantially the sheer bulk of the current physics course in order to fulfill its purposes within the time allotted to the sub- ject. The material that remains in our selection still leaves a one- year course more crowded than the teacher would like. In the next phase of our work, we may learn where to cut still further. 70 CHAPTER 3— EXPERIMENTATION IN SCIENCE Point of View Ideas for Experimental Work Chromotography and Electrophoresis Bacteriology Effect of Mineral Deficiencies on Plant Growth Effect of Concentration on Rate of Reaction Continuous Cloud Chamber How Big is a Molecule 71 Experimentation In Science POINT OF VIEW Teachers have varied opinions on laboratory work in high school sciences. Some teachers think that boys and girls at this age level are not capable or mature enough to handle laboratory work, and thus little is done. Others feel there is no need for individual work ; so they do most of the exercises by demonstra- tion. There are many others who believe very strongly that if students set up a piece of apparatus according to specific direc- tions and fill in the blanks on laboratory directions with the proper words that true experimental work has been performed. There are still others who specify that an exact number of "ex- periments" be performed in each course and who give no credit for the course until all assigned experiments have been com- pleted. There are isolated cases where the teacher believes that all of the work in the science class shall consist of laboratory exercises and projects. And, unfortunately, there are some cases where forty or more science students have been placed in a class and the teacher feels that it is impossible to handle this number in the laboratory — and this is demanding too much of the teacher. Most of these approaches have important elements in them, but they do not place experimental work in the proper perspec- tive. No one will argue that good demonstrations are not impor- tant, but they will not do the complete job — demonstration versus individual experimentation is not an either-or proposition. Students should have both experiences. Somewhat in the same light there should be no argument concerning laboratory exer- cise versus experimentation for some students. To orient stu- dents and to develop correct laboratory techniques, some labora- tory exercises might be essential, but they should not be used to the exclusion of all investigations on the part of the individual student or small groups of students. Whatever the physical con- dition of the science department might be, whatever the feelings might be in regard to demonstrations, laboratory exercises, time to do the work, and the educational level of the students, no class should be permitted to read and talk science week after week with no contact with real experimentation. This point of view has been well stated by Robert Carleton in the article "Physics Hazard, Math Hazard, or Teacher Hazard," The Science Teach- er, National Science Teachers Associations, 22:173-175, Sept. 72 1955: "There is no school too small or too impoverished to pro- vide many opportunities for us to have real experiences with the solid core of true science — finding answers by experiment. Stu- dents who receive no laboratory instruction in science have been defrauded as if they had been taught a false science. Demon- strations, science clubs, science fairs, audio-visual devices, field trips, textbooks, and other aids have a place in resourceful teaching of science. But when the laboratory and its emphasis on the investigation or research-type exercise disappears from day-in, day-out science teaching, then the heart and chief in- spiration of science as a form of human endeavor have been lost." Another viewpoint on this modern approach to laboratory work is provided by R. W. Lefler in the article "Use Your Science Lab Scientifically," NEA Journal, National Educational Association, Washington, D. C, February 1954, page 83-84. In this article the idea is advanced that the science teacher should pretend that he is director of research in a laboratory in which approximately thirty scientists are employed to work as teams — the scientists being the science students. As the teacher (director of research) guides the work of the research teams during the nine months of schooling, he gradually real- izes that he does not have to pretend that he occupies this posi- tion but this actually becomes his task. This change emerges because of the activities involved : the selection of team chair- men, conferences with group chairmen for overall planning, working with specific groups and individuals on their particular problems, and hearing progress reports from individuals and groups. In the job as director of research, the teacher must lead the students into profitable investigations ; he must have ap- propriate materials, books and apparatus available ; he must advise groups and individuals, but should not provide answers to the important questions which arise, nor should he expect to know all the answers ; he must use his group chairmen as assistants to do many of the routine tasks in the laboratory, thus providing time for conferences ; and he must encourage extra-class activity, ranging from homework on a particular phase of the subject being studied to a detailed investigation of a problem growing out of the work. If these types of activi- ties emerge, the director of research should have an entire year of pleasant working days, because he will see individual stu- 73 dents grow as he helps them to learn science. He will be able to detect growth in their maturity to find answers to real prob- lems through experiments, reading, and through all methods which they must use to obtain information to validate or dis- prove hypotheses. In short, the school days will be enjoyed and "time will fly." This viewpoint of the place of the high school laboratory in the mid-twentieth century has been explained in a thorough manner by Robert Stollberg in the chapter "Learning in the Laboratory," Science Education in American High Schools, The Bulletin of the National Association of Secondary-School Prin- cipals, Washington, D. C, January 1953, pages 100-110. In this discussion Stollberg presents what are called "hallmarks of good laboratory education in high school science:" 1. Classroom and Laboratory Work Should Be Closely In- tegrated. ... On some occasions, classroom discussion may well prepare the pupil for laboratory experience ; on others, problem situations encountered in the labora- tory profitably lead to spirited productive classroom dis- cussions. 2. Flexibility of the Laboratory Schedule Is Highly Desir- able. Rigidly scheduled periods for laboratory experiences make it difficult to integrate classroom and laboratory learning and to attack in the laboratory problems which spontaneously arise in the classroom. . . . 3. Seeking Answers and Finding Information Is a Proper Function of a Laboratory. . . . Whether laboratory experi- ence is centered around measurement, demonstration, or observation, the bulk of laboratory learning should be devoted to seeking answers to problems and finding in- formation which is desired. 4. Real Problems Are Most Desirable in Laboratory Learn- ing. . . . Problems such as 'How does water pressure in this community vary from day to day?' 'Is the lighting adequate in this laboratory ?' 'Is our basketball team getting adequate nutrition and rest?' and 'What happens if we bubble pure oxygen into our acquarium?' are ex- amples of real problems which can be approached in the laboratory. . . . 74 5. Practical Application Should Be a Part of Laboratory Learning Wherever Possible. . . . The coefficient of thermal expansion can be illustrated in the form of a bimetallic thermometer or expansion joints in a bridge or a roadway; buffer action can be illustrated in the form of headache tablets, photographic chemical solu- tions, etc ; the principle of diffusion can be applied to water absorption roots, soaking of dried fruits, and nourishment of cells. . . . 6. Cooperative Planning By Pupils and Teachers Is a De- sirable Part of Laboratory Learning. Guided discussions can serve to identify the problem and to set up patterns of solving it. . . . 7. Improvization of Apparatus By Pupils Is a Valuable Phase of Laboratory Learning. . . . While pupils are pro- viding and setting up their own equipment, they often encounter unpredicted problems which must be solved before they can go on. These are problems of the most genuine character — they are not imposed by the teacher — they must be recognized and solved largely by the pupil himself. . . . 8. The Use of the Laboratory Manual May Well Be Con- fined To Its Value As a Reference. . . . Pupils seeking to establish their own laboratory procedures may consult a variety of such manuals for suggestions and for data, yet not follow any one of them "cookbook" style. . . . 9. The Boundaries of the Science Laboratory Should Be Considered As the Actual Boundaries of the Pupil's Ex- perience. That is, the laboratory should be thought of as an approach, as a method — not merely as a place. . . . 10. Long-term Laboratory Activities Are to be Encouraged. This is true of all sciences, but particularly so in life science where many processes are by nature compara- tively time consuming. . . . 11. Note Taking, Data Recording, and Sketching Should Be Truly Functional. . . . Notes should be taken when pupils actually need them, data should be recorded when re- cording helps clarify them, or when they are needed for future reference, and sketches should be made when they are actually needed, and when they are not already available. . . . 12. Reports of Laboratory Activity Should Have Purpose and Meaning. . . . An ideal way to make a report func- tional is to have one pupil (or a group) describe his activities to the remainder of the class, who presumably have been occupied in other activities. . . . 13. Live Materials Are the Desirable Media for Biological Science Laboratory Experiments. ... It is a travesty on meaning that biology is a study of life, while most of the laboratory work is done with dead materials. . . . 14. Problem Solving is Desirable in Life Science Laboratories, too. Altogether too many life science laboratories con- fine their activities to almost casual observation of daily phenomena or preserved specimens, and to a structure of organisms. . . . 15. Diagraming and Sketching of Experimental Materials Should be Examined with Great Caution. . . . There is considerable research to show that emphasis on exact representation and artistic skill in drawing bears no fruit in terms of pupil understanding. The practice of having pupils trace drawings from books or manuals is of even less value. The degree to which experimental work is performed in a laboratory and the enthusiasm with which the students tackle a problem involving experimentation will depend to a great extent on the example set by the teacher. If problem solving activities are an integral part of science teaching philosophy and learning, it is likely that experimentation will not be neg- lected. If by example of the teacher the laboratory is considered as "headquarters" for pupils to raise and define worthwhile problems, then one can easily detect this activity going on at almost any time of the year. If by his actions the teacher generates the feeling in the laboratory that scientific exploration is similar to detective work and that everyone can participate in it in one way or another, many an interesting case will be in- vestigated at varying levels of complexity. If the students early in the course learn from the work of the teacher the meaning and use of controls in experimentation, much of the "cookbook recipe" type of laboratory work will give way to investigations that produce data from which students can catch a glimpse of the problem and detect other profitable approaches to the prob- lem. If the forming and testing of hypothesis and the interpret- 76 ing of data becomes a daily part of the science work because of encouragement on the part of the teacher, students will plan experiments with more care and will organize, arrange, and analyze data. If a proper balance between student exploration and teacher guidance is maintained, the teacher will be assured that his help is enabling the student to mature in his habits and thinking, and the student will not feel that he is in a sink or swim condition or in the position of being "fed from a silver spoon." Ideas for Experimental Work There is an excellent discussion on experimental work in the November 1950 issue of The Science Teacher called "Making the Most of Experimental Exercises" by Ellsworth S. Obourn, pages 170-171. In his discussion Obourn first points out that the rise of modern science dates from the classic experimental work of Galileo and his contemporaries, and that our amazing accumulation of scientific knowledge since that time has resulted from the ability of the scientific workers to devise ways of testing the truth or falsity of hypotheses. The study of the history of modern day science shows conclusively that collect- ing and testing evidence are the specific things that set science apart as unique in the field of learning. Thus the high school "science teacher has at his disposal one of the most potent de- vices of learning ever devised by the mind of man." He then points out that it is difficult to define a measure for a good experimental exercise. The following criteria are sug- gested for consideration by the teacher : "1. Is the purpose of the experimental exercise stated clearly as a question? 2. Is the variable factor or hypothesis to be tested identified? 3. Are the control factors identifiable ; are they adequately provided for? 4. Are the directions clear and concise? 5. Do the directions permit some latitude for the pupil to use his initiative and resourcefulness in planning and devising, or are they 'cookbookish' in nature ? 6. Is the conclusion to be reached by the experimental exer- cise closely related by a logical pattern to the stated purpose? 77 7. Is provision made for identifying the assumptions that are basic to the acceptance of the conclusion?" A strong point is made in this discussion concerning the neg- lect in many science classes of the role of assumptions in accept- ing or rejecting conclusions. This practice should receive the careful attention of students and teachers, since many of the ideas accepted as true are based upon assumptions, implied or stated. To illustrate this point Obourn discusses the following experimental exercise. "The Elements of a Fertile Soil — Pur- pose: Do some kinds of soil bacteria help plants to grow? Direc- tions : Secure two pots of soil from a field in which good crops of clover or beans are growing or have recently grown. Heat the soil of one pot to 130° F. and keep it at that temperature for twenty minutes in order to kill the bacteria in the soil. Then plant in each pot some seeds of clover and beans. Keep both pots well watered and in good growing light and tempera- ture. When the young plants are a month old, what differences can you determine in growth and in root conditions? Conclusion : Sometimes soil bacteria do aid the growth of plants. "The acceptance of this conclusion rests upon certain things that are taken for granted as true (assumptions). Among these are the following : 1. The soil in which clover or beans grow contains bacteria which aid the growth of plants. 2. Heating to 130° F. for twenty minutes kills the soil bacteria. 3. Soil bacteria is the sole cause of the differences produced in growth and root structure. 4. The seeds used in each pot had the same rate of germi- nation. 5. Clover and bean seeds will germinate, and their plants will grow, in soil which has been heated to 130° F. 6. One month is sufficient time to determine a difference in growth and in root structure of plants in the two pots. 7. A temperature of 130° F. does not break chemical com- pounds in the soil into elements or other compounds which aid the growth of plants. "These assumptions would seem individually necessary and collectively sufficient to the acceptance of the stated conclusion. In teaching experimental exercises in any science subject, it is 78 very essential that consideration be given to the identification and evaluation of the assumptions which underline the con- clusions reached." As an example of what might be done during the early part of the course to promote this type of laboratory work, the teacher might consider the following problem. An experiment (laboratory exercise) commonly performed in the high school chemistry course is the preparation of oxygen by heating potas- sium chlorate in the presence of manganese dioxide. The pro- cedure for doing this experiment is to fill a hard-glass test tube 1-4 full of a mixture of one part manganese dioxide and two parts potassium chlorate by weight. After the test tube is clamped in the correct position and the glass delivery tube in- stalled properly, the generator is heated by a Bunsen burner and oxygen is collected in bottles by the displacement of water. After the oxygen is tested for certain properties, the common procedure is to say to the students "the experiment is finished, clean up the work space, throw the mixture that is left in the test tube into the disposal jar, store the apparatus and get ready to go to your next class." If this is all that is done, this experiment might easily be classed as a laboratory exercise. This can be quickly changed to an experiment by asking such questions as : Do you think some of the manganese dioxide was consumed in the experiment even though the literature says this compound acted as a catalyst in this reaction and was not consumed? What might one do to check this? Since there is a large amount of the materials left in the test tube, is there any way by which they can be re- covered? If they were recovered, could they be used to produce more oxygen? The equation for the reaction indicates that po- tassium chloride is formed. How can one prove this? As question after question is asked the students, their think- ing will bring out the point that the solubility of the substances in water might be a good point at which to tackle the problem. When the thinking reaches this point, have the students find the data on potassium chlorate and chloride in a table which gives the physical constants of inorganic compounds. In this table, under solubility in one-hundred parts, will be found this information: In cold water at 0° C. the solubility of potassium chlorate is 3.3 ; for potassium chloride it is 27.6. In hot water (100° C.) the solubility of potassium chlorate is 57 and for 79 potassium chloride it is 56.7. For manganese dioxide the in- formation shows that it is insoluble in either cold or hot water. This information should provide the students with a clue as to how to begin their work on this angle of the problem. Since potassium chloride is nine times more soluble in water at 0° C. than is potassium chlorate, they should see that a solution of the two might be separated by cooling to this temperature. If one wishes to go further in this investigation, he might evaporate some of the original filtrate to dryness and thus obtain a mixture of potassium chloride and potassium chlorate. For one or more interested students, present this problem : From the loss of weight (oxygen) upon heating compute the percent of each salt in the mixture. The preceding discussion will raise a question in one's mind concerning the advisibility of using laboratory manuals in the various science courses, as the entire basis for the experimental program. This was the purpose. There has been a heated debate going on for years and is still continuing on this question. There is a strong feeling, though, that slavish adherence to a labora- tory manual will rob the students of many fruitful experiences. This is not to say that manuals have not been prepared with care. In many cases they have been developed by outstanding science teachers, and many years of w T ork have gone into their preparation. The weakness is that little remains for the stu- dent to do except to follow directions. In some instances an attempt has been made to remedy this weakness by giving addi- tional exercises or further investigations. Unfortunately, this plan for improvement has been defeated, because students and teachers have developed a habit of looking for detailed direc- tions to carry out an exercise. Also the time factor has become such a determining element in completing a certain number of experiments each week, month, and year, that little effort can be devoted to a more rewarding type of science experience. Do these remarks imply that no laboratory manual be pur- chased? The answer is no. Well prepared laboratory manuals should be in every department. They contain excellent ma- terial. A variety of manuals should be available to the teacher and students at all times. But it is not necessary to have thirty of the same title. A half dozen copies of six or eight different manuals, it appears, will provide a source of research materials that can be used to a distinct advantage. If these are used as 80 a source of ideas and procedures to be used in solving laboratory problems, and if the student prepares his own report instead of filling in the blanks in the laboratory manuals, they will en- able him to develop a better grasp of science. Thus he will gain experience in organizing his ideas and in the effective use of language in presenting them. These are important objectives in experimental work. To provide ideas on new topics for experimental work, on new approaches, on other techniques, and on new subject- matter, the following exercises are presented. These are not commonly found in laboratory manuals now on the market. Perhaps in this limited number, one might find the idea for which he has been searching. Perhaps this will provide sources of information from which dozens of suggestions can be found. CHROMATOGRAPHY AND PAPER ELECTROPHORESIS Principles : Two extremely valuable techniques that have been widely used in science and technology in recent years are chro- matography and electrophoresis. Both methods are used to sep- arate complex mixtures into the individual components. This separation procedure avoids destruction of certain more unstable components that would have occurred if some other methods such as distillation or crystallization had been employed. Furthermore, many separations previously impossible to make can be accom- plished by these methods. In certain forms, chromatography and electrophoresis offer a simplicity of operation which permits a much more rapid accumulation of information than other meth- ods permit. Chromatography is used most widely in two forms — column chromatography and paper chromatography. In the column form, separations are achieved by the filtration of a solution containing various components through a column of finely-divided adsorbing material. The components are adsorbed on this material and can be removed later by passing certain liquids through the column. Since the different components are not removed with the same ease, some will move down the column faster than others. In paper chromatography, a sheet of filter paper can serve like the adsorbing material used in the columns. In this procedure *Carl G. Baker, Laboratory of Biochemistry, U. S. National Cancer In- stitute. The Science Teacher, May, 1956. 81 much smaller amounts of material are required and much less time is necessary to "complete a run." Electrophoretic procedures are based on the knowledge that the components of mixtures carry electrical charges of varying amounts, and they will therefore move at different rates in a salt solution through which a current is passed. Of course, those components carrying a net negative charge will move toward the positive electrode and those with a net positive charge will move toward the negative electrode. In paper electrophoresis, the mix- ture to be separated is placed on a strip of paper after the paper is moistened by the solution, and the ends of the strip are placed in two containers filled with the solution. Electrodes are sub- merged in the container and direct current is passed through the solution. Separation of the components is easily observed if the differently-charged components are of different colors. When the components being separated are colorless, some means of detection must be employed. It can be done through visualization by staining with dyes or by forming colored prod- ucts through a chemical reaction, or it can be done by chemical tests. When radioactive materials are separated, detection can be done with photographic film. When proteins are studied, they can be visualized with the dye, bromophenol blue. Amino acids can be seen by reacting them with ninhyclrin. Chloride can be detected (after elution of different portions from the chromato- gram) by reacting with silver nitrate. Some substances absorb ultraviolet light, and this property can be utilized for their de- tection and measurement, etc. Procedures : A. Column Chromatography: 1. Preparation of the adsorbing column: An ordinary piece of glass tubing, outside diameter of about 8 to 10 millimeters, about IV2 to 2 feet in length, is em- ployed. Ordinary absorbent cotton is forced in loosely at one end of the tubing for a distance of about 1 inch. With the tubing held in a vertical position (with the cotton at the lower end) , the adsorbing material is in- troduced into the tubing in small portions. A small funnel is useful for loading the tubing. As the ad- sorbent is added to the tube, the tube is gently tamped frequently upon a wooden surface to pack down the adsorbent. The adsorbent used is magnesium carbonate 82 (USP). After the height of the adsorbent has reached about 6 to 10 inches, it is ready for the addition of ligroin (petroleum ether) to the column. After all the adsorbent is thoroughly wet, the column is ready for chromatography. It is convenient to place a short piece of rubber tubing carrying a clamp (a screwtype pinch clamp is best) on the lower end of the tubing for con- trolling the flow of liquid in the column. Preparation of the extract of leaves: A large green leaf (spinach works well ; in the demonstration given at the National Institutes of Health a leaf from a bryophylum plant was employed since some leaves hap- pened to be available) is cut up into small pieces, (about y± cm. square) the cut portions are placed in a mortar that contains a little sand and about 70 cc. of ethyl alcohol (other alcohol, such as rubbing alco- hol, should also work ; the school doctor or a local phy- sician could help obtain the ethyl alcohol) and the contents are ground with a pestle. After the leaf is thoroughly ground, the liquid is filtered through filter paper (if no filter paper is available, the clear overly- ing solution can be poured off after the sediment is allowed to settle) . To the green alcoholic solution is added 25 cc. of ligroin and the two are thoroughly mixed. After the mixture has stood for a few minutes two layers appear; the upper layer is the ligroin solu- tion. The upper layer is separated from the lower layer and is poured into a flat dish. The process is repeated twice by addition of fresh ligroin to the lower layer (these separations can be done best with the aid of a small separatory funnel, but if this piece of apparatus is not available, the upper layer can be removed by sucking it up into a tube very carefully, or if great care is taken it can be poured off, making sure that none of the lower layer is included) . The green solu- tion in the flat dish is allowed to evaporate to dryness (this step can be speeded if a gentle blast of air is passed over the dish). After evaporation is complete (and as soon thereafter as is convenient) the residue is dissolved in 3 cc. of ligroin. Loading the column: The column of adsorbent should be wet with ligroin, but no free ligroin should extend 83 above the adsorbent more than about Vs inch. The 3 cc. of ligroin containing the leaf pigments is carefully poured onto the top of the column (it should be done slowly to avoid stirring up the top of the column) . As soon as the green solution has passed into the adsorb- ent, fresh ligroin is carefully added, and after addi- tional ligroin has passed into the column, the tubing above the column is filled with ligroin. After ligroin has passed through the column for two to three hours, several colored bands of leaf pigments can be seen on the column. The pigments are chlorophylls, xantho- phylls, and carotenes. 4. Materials : a. Glass tubing, 8 to 10 mm. outside diameter, about iy 2 to 2 ft. long. b. Small amount of absorbent cotton. c. Adsorbents: Magnesium carbonate, USP (can be obtained at a drug store or chemical supply house). Other adsorbents can be used ; inulin, alumina, cal- cium carbonate, and possibly powdered sugar. d. Green leaves (frozen spinach can be used) . e. Mortar (holding about 300 to 500 cc), pestle and a few grams of sand. f. Ligroin (petroleum ether) — the low boiling frac- tion (b.p. 30-75° C.) of petroleum — about 500 cc. g. Alcohol, preferably ethyl, but rubbing alcohol should work — about 500 cc. h. A flat dish, such as an evaporating or Petri dish — holding about 100 cc. i. Several containers, such as Erlenmeyer flasks or beakers — about 50 and 150 cc. j. Convenient articles: Small glass funnel — about 35 mm. diameter Medium glass funnel — about 120 mm. diameter Filter paper (e.g., Whatman No. 4) about 200 mm. diameter Rubber tubing, about 3 inches long, about 6 mm. inside diameter Clamp — screw type (Hofmann) Small scissors Separatory funnel — about 100 cc. size A few 5 cc. and 10 cc. pipettes 84 B. Paper Chromatography: A large test tube, about 150 mm. long and about 20 mm. in diameter, is fitted with a cork stopper into which has been placed at its smaller end a small wire hook (the hook can be made from a wire staple). A 70f< (by volume) alcohol-water solution is placed in the test tube up to a depth of about 15 mm. Narrow strips of filter paper, Whatman No. 1, about 6 mm. wide and long enough to reach from the wire hook down into the alcohol solution for about 5 to 10 mm. are prepared. Small holes are placed close to one end in order that the strips may be suspended on the hooks. About 15 mm. from the other end a heavy dot of ink is made (the ink from a Papermate ball-point pen has been found to be satisfactory since it contains three different colors). After the test tube is placed in a vertical position, a strip is hung from the wire hook, so as not to allow the strip to stick against the side of the tube. It will be noted that the alcohol solution rises in the paper by capillary action. After a half hour, separation of the components can be noted as colored bands at different levels on the paper strip. 1. Materials: a. A large test tube, about 150 mm. long and about 20 mm. in diameter. b. A cork stopper to fit the test tube into which is placed in its smaller end a fine wire hook. c. A 70 /f (by volume) alcohol-water solution — about 10 cc. Ethyl alcohol is preferred, but other alcohols, including rubbing alcohol should work. d. Filter paper, such as Whatman No. 1, cut into strips as described above. Whatman No. 4 paper and other filter papers will also work. e. Some colored substance containing different col- ored components, such as certain inks or stains. C. Paper Electrophoresis: 1. Preparation of the buffer solution: One teaspoonful of ordinary table salt (5.25 grams of sodium chloride) and 1/4 teaspoonful of baking soda (1.2 grams of so- dium bicarbonate) are dissolved in 12 ounces (360 cc.) of tap water. The solution may be kept for several days. For an experiment using 200 volts the buffer 85 solution is diluted 20 times. With lower voltage, less dilution may work better. 2. Preparation of the filter paper: Several strips of filter paper, Whatman No. 1, are cut about 50 mm. wide and about 320 mm. in length. 3. Setting up the experiment: A filter paper strip is mois- tened with the buffer solution and is placed between two plates of window glass, 2 inches by 8 inches, such that the ends of the strip extend beyond the glass plates approximately an equal distance at each end. The excess buffer solution is squeezed out by pressing the glass plates together. The glass plates are taken apart, and care is taken that the paper is not torn and that it lies on one of the plates smoothly. A line of ink (ink from a Papermate ball-point pen is satisfactory) about 1*4 inches long is drawn on the wet paper at right angles to the longer dimension of the paper ap- proximately in the center of the paper strip (be care- ful not to tear the paper!) The strip is again squeezed between the two plates and four spring-clip clothes- pins are placed near the corners of the glass plates to hold them together. The glass plates are placed between two flat dishes such that the edges of the dishes support the plates and allow the filter paper that extends beyond the ends of the plates to rest in the dishes. Buffer solution is then poured into each dish to a depth of at least 1 cm., but not closer to the rim of the dishes than about 1/4 inch. The end of a graphite electrode (made by re- moving the central graphite rods from regular flash- light dry cell batteries) is placed in the solution in each dish and a current of about 10 milliamperes and a volt- age of 200 volts is passed through the system. After about fifteen minutes different rates of migration of the components have produced colored bands on the paper strip (with the Papermate ball-point pen ink a yellow band has migrated ahead of a pink band toward the positive electrode ; a neutral blue band has remain- ed at the site of application of the ink line) . 4. Materials : a. A few grams of table salt. 86 b. A few grams of baking soda. c. Several sheets of filter paper, e.g., Whatman No. 1. Other types of filter paper, such as Whatman No. 4, or blotting paper will work as well. d. Two glass plates, 2 inches by 8 inches. Ordinary window glass may be used, or glass plates, *4 inch thick, work well. e. Four spring-clip clothespins. f. Two flat glass dishes, such as small flat icebox dishes or Petri dishes. g. A colored material containing different colored components, such as certain inks or stains. h. Two graphite electrodes. i. A direct current power supply, preferably with variable control providing up to 250 volts. Such power supplies can be purchased, but are some- what expensive. A satisfactory one can be built from a kit for about $30 or from second hand parts obtained from a radio shop. Somewhat lower voltage can be employed if the undiluted buffer is used and/or if the experiment is run for a longer time, but the highest voltage possible with- out overheating is recommended. BACTERIOLOGY* Despite the almost universal occurrence and the inescapability of contact with bacteria, there are few forms of life as little known and understood by so many people. Their importance in disease, agriculture, and industry makes it desirable to direct the attention of all students toward them. Few, if any, forms of life are as personally important to all people as are bacteria. For the effective demonstration of the existence, properties, and activities of bacteria, relatively little equipment and few materials are required. Most of the equipment used is the same as that of the chemistry laboratories, and the necessary ma- terials are readily available. The Preparation of Nutrient Media The media used for the cultivation of bacteria range in com- plexity from cooked, sterilized potato slices to involved synthetic "Department of Botany, Duke University, July 21-25, 1952. 87 media containing accurately measured quantities of known chemical compounds, refined vitamins, growth factors, etc. How- ever, the most commonly used of the media is a mixture of beef extract and peptone dissolved in water and solidified with agar or gelatin. This medium, easy to prepare and to use, sup- ports the growth of a wide variety of bacteria. Equipment Required: 1. A 1 liter flask 2. A sauce pan or water bath (A double boiler of suitable size can be substituted for the above) 3. Ring stand and Bunsen burner 4. Four 250 ml. flasks and (or) 30-40 test tubes 5. Graduate cylinder Materials Required: 1. Beef extract. This may be in a form especially prepared for bacteriological media, obtainable from biological supply houses, or in the form of beef bouillon cubes or beef broth, obtainable from most grocery stores. 2. Peptone. This is a desirable but not absolutely essential ingredient of the medium. 3. 500 ml. of water. Not necessarily distilled. 4. Agar or gelatin. These may be obtained from biological supply houses, or easily available Knox Gelatin may be used. Procedure: 1. Bring 100 ml. of water in a liter flask or sauce pan to boiling over an open burner ; and after removing it from the fire, dissolve 3 grams of beef extract and 5 grams of peptone in the hot water. Then dilute to 1 liter. 2. Divide the liter of broth in two 500 ml. lots. Both lots may be solidified with agar or gelatin, or one lot may be retained for future solidification or used as a liquid medium. 3. To 500 ml. of the broth add 7.5 grams of agar or 75 grams of gelatin. 4. Place the 500 ml. of agar, peptone, beef extract, water 88 mixture in a double boiler or in a liter flask immersed in a water bath, and heat until the agar or gelatin is thoroughly hydrated (approximately 30 minutes in a boiling water bath.) 5. Pour the hot medium into the 250 ml. flasks, putting approximately 125 ml. of medium in each flask. The remaining medium may be used to fill test tubes to one- third of their capacity. 6. Stopper flasks and tubes with snug-fitting cotton plugs. 7. Sterilize by heating in a pressure cooker for 30 minutes at 15 pounds pressure or 45 minutes at 10 pounds. 8. If a pressure cooker is not a available, the medium may be sterilized by being heated in boiling water for one hour after the medium is melted. Keep the medium at room temperature for 24 hours ; then repeat the melting and one hour of heating. 9. The nutrient broth not solidified may be placed in cotton- stoppered flasks, sterilized, and retained for future use. 10. The test tubes of agar should be permitted to cool and solidify in a sloped position. The Microorganisms of the Atmosphere The number of microorganisms to be found in the atmosphere is usually relatively low. This should not be surprising when one recalls that most bacteria are easily killed by drying and that the amount of moisture in the air is usually low. Addi- tionally, the near absence of suitable food materials prevents the reproduction of those organisms which do survive dessica- tion. Despite the fact that the total number of microorganisms in the air is low, there are many types, including bacteria, molds, yeasts, and actinomycetes. Equipment Required: 1. Sterile Petri dishes. Petri dishes should be sterilized by being heated in an oven at a temperature of 150° C. to 170°C. (302°F.-338°F.) for two hours. 2. Bacteriological transfer loop or needle. 89 Materials Required: 1. Nutrient agar or gelatin. An agar medium is preferred because it has a higher melting point than gelatin and because it is not digested by as many bacteria as is gelatin. 2. Nutrient agar slants in test taubes. (These are not abso- lutely necessary but may be desirable for the isolation and maintenance of pure cultures.) Procedure: 1. Melt previously prepared nutrient agar or gelatin by heating in a water bath. 2. Pour 15-20 ml. of the melted medium into each of 6-12 Petri dishes. When pouring medium, tip one side of the upper (larger) half of a Petri dish and quickly pour the medium into the lower (smaller) half of the dish. Do not remove the upper half, as this would in- crease the number of contaminants falling into the Petri dish from the air. 3. Permit the medium to solidify with the Petri dishes on a level surface. (This takes from thirty minutes to one hour.) 4. After the medium has solidified, remove the covers from the Petri dishes and permit bacteria, etc. to impinge upon the surface of the medium. a. Do not expose any of the plates for less than fifteen minutes. b. It may be desirable to expose one plate for 15 min- utes, another for 30, and another for 1 hour. c. Comparisons may be made of the number of bacteria in the classroom and the number in the outside air. 5. Invert the plates so the agar-covered surface is up, and store them at room temperature (approximately 75° F.) for two days. 6. After being incubated for two days at room temperature, colonies of bacteria consisting of thousands of individual cells will have grown wherever a single living bacterium fell onto the surface of the medium 58 hours previously. By counting the number of macroscopically visible colonies, one can determine how many microscopically 90 visible cells fell during the time the surface of the med- ium was uncovered. 7. Since all of the cells of a colony are descendants of a single individual, transfers can be made from colonies to agar slants in test tubes. In this way pure cultures are established. 8. Transfers are made by heating a wire loop or needle to red heat in an open flame. Tip the Petri dish cover enough to permit inserting the needle into the dish. Touch the tip of the needle to a colony, withdraw the needle, quickly unplug a test tube, and streak the needle back and forth across the entire length of the slant. Re- place the cotton plug in the test tube, and again heat the needle to red heat to sterilize it. 9. Transfer a number of colony fragments to test tubes in order to establish pure cultures for additional obser- vation and experimentation. Bacterial colonies may be satisfactorily distinguished from mold and actinomycete colonies by macroscopic examination. Testing Antiseptics There are many methods of evaluating antiseptics, most of them of considerable complexity. There is, however, a simple method of comparing the relative efficiences of germicides. This method, while reliable, measures only one of the factors which determine the usefulness of an antiseptic — that is, its bacterio- static or bacteriocidal effect under laboratory conditions. Equipment Required: 1. Petri dishes. The number required will vary with the number of antiseptics tested and with the number of kinds of bacteria used. Not more than two antiseptics should be treated in one plate. 2. Small paper disks cut from filter paper. A convenient way to prepare disks of uniform size is to use a paper punch of the type used to punch holes in notebook paper. 3. Some method of sterilizing the Petri dishes. This may be done by heating the Petri dishes for one to two hours in an oven. 91 4. Transfer needle 5. A pair of forceps 6. A Bunsen burner or an alcohol lamp 7. A small beaker or other glass container Materials Required: 11 flasks or test 1. Sterile nutrient agar or gelatin in g tubes. 2. Alcohol 3. Commercial antiseptics : a. Mercurochrome f. ST. 37 b. Tincture of iodine g. Odorono c. Merthiolate h. Alcohol d. Listerine i. Penicillin e. Pepsodent lozenges 4. Bacteria. Pure cultures may be obtained from any of a number of biological supply houses at a moderate cost. If such cultures are to be used, they should be ordered approximately two weeks before the time scheduled for their use. Recommended organisms are Staphylococcus albus or Micrococcus corallinus or Sarcina subflava. These organisms are very responsive to most antiseptics. Actually it is not absolutely necessary to purchase pure cultures, since they may be obtained by selecting colonies from Petri dishes containing nutrient medium previously exposed to the air. If this is done, select a colony which is yellow in color. Such chromatophores from the air are most apt to be susceptible to antiseptics. Procedure: 1. Melt the sterile nutrient medium by heating from 20-30 minutes in a water bath of 100° C. 2. Allow tc cool unitl the water temperature is 45-50° C. (The tubes or flasks of media should feel slightly warm, not hot.) 3. Inoculate the melted, cooled medium. a. Heat transfer needle in open flame. b. With the needle transfer a small amount of the se- lected bacterial colony or culture to the melted medium. c. Shake the inoculated medium to distribute the inocu- lum. 92 4. Pour the inoculated medium into sterile Petri dishes. (Lift covers, but do not remove. It is necessary to do this rather rapidly since the medium will solidify quickly.) 5. After the inoculated medium has solidified in the dishes, dip the forceps in alcohol and ignite the alcohol to steri- lize them. 6. With the forceps pick up a filter paper disk, dip in an antiseptic, permit it to drain briefly, and by tipping the Petri dish cover place the disk on the surface of the medium. (Not more than two disks on each plate.) 7. Invert the plates and leave at room temperature for 24-48 hours. After this length of time the bacteria will have increased tremendously in numbers, causing the medium to appear opaque except in circular zones around the antiseptics. The diameter of the zone of growth in- hibition is a measure of the effectiveness of the germicide. DEMONSTRATION OF THE EFFECT OF MINERAL DEFICIENCIES ON PLANT GROWTH A. In Soil Ordinary flower pots or tin cans provided with drainage holes in the bottom can be used as containers. Soils of con- trasting characteristics should be used, for example — a heavy clay, a good loamy garden soil, a sandy soil or even a fine sand. Seedlings can be transplanted, or seeds germi- nated in the containers. Sunflower, tomato, tobacco, corn, or almost any other annual plant can be used. Ordinary commercial fertilizers might be used. The stu- dents can calculate the surface area of their pots and apply fertilizer at the rate recommended locally for the plants being studied. A good series would be controls receiving no fertilizer, 1/2 the recommended rate, the recommend rate, and twice the recommended rate. B. In water cultures These are best adapted to demonstrating deficiencies of particular elements. Plants can be grown in mason jars, crocks, or metal containers coated on the inside with asphalt paint. The plants can be supported by wads of cotton or stoppers with holes in them. There is no best solution for growing plants, but the following is satisfactory. "'Department of Botany, Duke University, July 21-25, 1952. 93 Molar Stock Solutions ml. per liter ml. per 18 of nutrient liters of Compound Molecular wt. sol. nutrient sol. KH 2 P0 4 136.14 g. 1 18 Ca(N0 3 )2.4H 2 236.16 g. 5 90 MgSO, 120.38 g. 2 36 Bottles of molar or half molar stock solution should be pre- pared and the solution in which the plants are to be grown can then be made up as needed. If half molar stock solu- tions are used, double the above quantities in preparing the nutrient solution. In addition to the elements needed in large quantities, several other elements which are required in very small quantities are supplied in the following solution : grams/liter Boric acid (H 3 B0 3 ) 2.86 Manganese chloride (MNC1 2 .4H 2 0) 1.81 Zinc sulfate (ZnS0 4 .7H 2 0) 0.22 Copper sulfate (CuS0 4 .5H 2 0) 0.08 Use one cc. of this solution per liter of nutrient solution or 20 cc. per 5 gallons. Dissolve 50 grams of ferrous sulfate in a liter of water (ferric citrate or ferric tartrate can also be used). Add 1.0 cc. of the iron solution per liter or 20 cc. per 5 gallons of stock nutrient solution each week. Sometimes when plants become pale in color (chlorotic) spraying the iron solution directly on the leaves with an atomizor will result in im- provement. Plants grown in this complete solution serve as controls and should make normal growth. To produce deficiences, the following modifications are made: Nitrogen Deficiency. Replace Ca(NO 3 ) 2 .4H 2 with twice the volume of molar CaCl 2 . Potassium Deficiency. Replace KH 2 P0 4 with an equal volume of NaH 2 P0 4 .H 2 0. Phosphorus Deficiency. Replace KH 2 P0 4 with equal volume of Molar KC1. Calcium Deficiency. Replace Ca(N0 3 ) 2 .4H 2 with twice the volume of molar NaNo 3 . 94 Magnesium Deficiency. Replace the MgS0 4 with an equal volume of Na 2 S0 4 . Iron and other trace elements should be added both to the complete and to the deficient solutions. EFFECT OF CONCENTRATION ON RATE OF REACTION Teacher Information Sheet: Purpose This experiment is designed to show the effect of a change in concentration of one of the reactants on the speed of a chemical reaction. It has four advantages over the traditional type of ex- periment : 1. The data may be interpreted on many different levels of student ability. 2. It is truly "open-ended" in the sense that the answer to the problems posed in this experiment can lead to new problems which in turn can act as bases for further experimentation and discussion. 3. It is adaptable to laboratory periods of varying lengths. 4. It employs many techniques of scientific measurements not often found in ordinary high-school experiments. Utilization Use this experiment in connection with the study of rate of reactions, but after the kinetic molecular theory is well grounded. The student is expected to make statements to show that he understands the purpose and method of the experiment. He then gathers his data, presents his graph, and conclusions from it in his own words. Preparation of Solutions The potassium iodate solution is made by dissolving 2 g of the substance in a liter of solution. The sulfurous acid-starch solu- tion is made as follows : To 5 g of starch in a 600 ml beaker, add about 10 ml of cold water, and stir to a paste. Add, with stirring, 200 ml of boiling water. Add 200 ml of cold water and allow to cool. Add 2 g of anhydrous sodium sulfite and 6 ml of 6 N sulfuric acid (add slowly while stirring 1 part of volume of concentrated sulfuric *Richard Siegel, Bronx High School of Science, New York. Scientific Experiments in Chemistry, Manufacturing- Chemists, Inc., Washington 6, D. C. 95 acid to 5 parts by volume of water contained in a Pyrex-brand glass vessel) . Make the volume become approximately 2 liters by adding water (shoulder high in a large acid bottle). This solution should not be used without pretesting if kept more than a week. Before using, shake to distribute starch uniformly. Directions The teacher must first decide about assigning different parts of this experiment among the students. The best method to make this assignment depends largely upon the time available. In a forty-minute period, each student should be able to do at least two determinations at one concentration. As many determina- tions should be permitted as time allows. The fact that scientists find the average figure for a number of determinations more re- liable than a single figure for one determination should be em- phasized. Four determinations for the time for one given concen- tration is better training for the student than four determina- tions at different concentrations. Any one of the four values which is far out of line should be dropped. Some error has been made. In such a case time reported would then be an average based on at least three determinations. The average time should be expressed to the nearest whole number of seconds. The students should be reminded that volumes in a cylinder or other volumetric apparatus are always read at the bottom of the meniscus (curved water surface) . The timing can be done in several ways. If each student has a watch with a second hand, or if the laboratory is provided with such a clock, timing becomes simple. If no such facilities are available, a metronome set at approximately 60 beats per minute may be used. In most schools, the music department should be able to loan this instrument. Where the metronome is used, the class must be cautioned to maintain absolute silence so that each student may count the metronome beats to himself. The fact that the metronome may not give exactly 60 beats per minute is not important as long as all the students use the same metronome. A simple pendulum can also be used as a timing device. Special mention should be made of the technique of prerinsing the cylinder with the solution whose volume is to be measured. It is employed to make sure that the solutions are not appre- ciably diluted by residual water. A 5 ml rinse solution is adequate. The following is a typical set of time intervals measured under the conditions set up in the table: (a) 70 sec (b) 84 sec (c) 104 96 sec (d) 140 sec (e) 208 sec. Intermediate concentrations may be used following the same pattern. Calculations It should be pointed out to the students that longer times mean lower speeds. Since the speed is inversely proportional to the time, the reciprocal of the time (1/time) is a measure of the speed of the reaction. This reciprocal is actually the fraction of the reaction that occurs per second. It may be necessary when illustrating this relationship to use simple whole numbers such as 1, 2, 3, and 4 for the number of seconds. Questions and Conclusions (Numbers refer to student experiment sheet.) (1) The only difficulty here is in expressing the concentration of the potassium iodate. It may be pointed out that, since the total volume is always the same, the concentration of iodate may be expressed in volume of iodate added. For scientific accuracy, it may be allowed to calculate the concentration in grams per liter or in moles per liter. (2) The answer to this question is expected to vary with the ability of the student. For the ordinary student, the answer would be that the speed of reaction increases with an increase of concentration. The student of college caliber should be able to say that the speed varies directly as the concentration. (3) The answer expected is the law of Mass Action. This question may be omitted if the principle is not in the syllabus. (4) In order to react, molecules must collide. Also sufficient energy must be present at the time of contact. (Consider no re- action between chemical materials in separate vessels.) (5) In cities the concentration of cars per unit area is greater than that in the rural areas. The chance of collision is greater in the cities. (6) An increase in concentration causes an increase in rate of reaction because an increase in the rate of collision has been produced. Optional Questions (These questions are intended for the superior student with a good mathematics background.) (7) A straight line passing through the origin has the general equation y (ordinate) = mx (abscissa) where m is the slope of 97 the line. In this case then, the equation would be S = mC. This equation can be tied in with the answer to Question 2 as follows : If C varies directly with S (C = S) then C equals a proportion- ality constant times S (C = kS). The top-grade student can then relate the slope of the line to the proportionality constant. (8) In the reaction 2A -f- B > C, A is a short way of writ- ing A -f- A. Anything proportional to two or more things simul- taneously is proportional to their product. The speed of this reaction is thus proportional to the concentration of A, times the concentration of B or, as far as A only is concerned, to the con- centration of (A) 2 . The equation required would then read S = kC 2 where k is a different proportionality constant from that in the equation for the straight line. (9) Eight being the third power of 2, 3 moles must be involved. Practical Applications (a) The reactant in this case, when either oxygen or com- pressed air is used, is oxygen. The oxygen is more concentrated in a tank of pure oxygen than in a tank of compressed air. The reaction with oxygen is therefore faster than that with com- pressed air at the same temperature and pressure and it pro- duces a higher flame temperature. The nitrogen absorbs a part of the heat and lowers the flame temperature. (b) Large particles would take so long to react that the cement clinker would not form during the time when the particle passes through the kiln. The smaller particles, because of the very large area of contact, react rapidly enough to produce Portland Cement clinker in a reasonable time. "Advertising" Chemistry in School Assemblies This experiment can form the basis for a short magic act in the assembly. The student who develops the best "patter" to go with the act, can be permitted to mix large volumes of the re- acting solutions in a tall cylinder on the auditorium stage, timing the reaction with a metronome whose beats are counted by the audience. By careful pretesting, he can predict for the audience the exact beat when the colorless liquid within the cylinder will turn dark blue. The time chosen should be one minute or less. The large volumes used will minimize errors in volume measure- ment. Long time waits cause restlessness in the audience. 98 EFFECT OF CONCENTRATION ON RATE OF REACTION Student Information Sheet: The Problem TO FIND THE RELATIONSHIP BETWEEN THE CONCEN- TRATION OF A REACTING SUBSTANCE AND THE RATE OF A CHEMICAL REACTION IN WHICH IT TAKES PART. The Attack You are to determine the time taken for iodine to form when you mix sulfurous acid (H 2 SO ?> ) with varying concentrations of iodic acid (HI0 3 ). The iodic acid solution is made from potas- sium iodate (KIO-.) . The sulfurous acid solution is made by add- ing sulfuric acid (H 2 S0 4 ) to sodium sulfite (Na 2 S0 3 ). More sul- furic acid is added than is needed to react completely with the sodium sulfite. The excess sulfuric acid causes the formation of iodic acid from the potassium iodate. Starch is added to show the presence of iodine (I 2 ) by the appearance of a dark blue coloration. The two chemical reactions involved are (1) 3H 2 S0 3 + fflO g ~> 3H 2 S0 4 + HI and (2) 5HI + HI0 3 > 3I 2 + 3H..0 Reaction (1) is slow, while reaction (2) is instantaneous. Since sulfuric acid is a stronger reducing agent than hydriodic acid (HI), reaction (2) cannot occur until all the sulfurous acid is used up in reaction (1). As soon as all the sulfurous acid has reacted, reaction (2) takes place, producing enough iodine in a small fraction of a second to give, with starch, the blue color that marks the end point of the reaction. Thus you measure the change in speed of reaction (1) with varying concentrations of iodic acid. Apparatus 100 ml graduated cylinder, stirring rod, 250 ml beaker, piece of white paper, watch with second hand, or metronome. *op. cit. 99 Materials Potassium iodate solution and sulfurous acid-starch solution. Directions Use the quantities of material on one of the horizontal lines in the table below as directed by the instructor. Measure the required volume of sulfurous acid in a dry grad- uated cylinder or in one previously rinsed with the sulfurous acid and pour the liquid into a 250 ml beaker. Rinse the cylinder with water. Then measure and add the required volume of water. Rinse the cylinder with about 5 ml of potassium iodate solution. Then measure the specified volume of potassium iodate solution in the cylinder. Place the beaker on a piece of white paper. Be prepared to measure time. Add the potassium iodate solution quickly to the beaker, stirring vigorously for a few seconds. Time should be measured from the instant all the potassium iodate is transferred to the beaker until the appearance of a blue coloration. Use the timing device that you have, and find this time interval. Repeat the entire experiment as directed by the instructor. In the "Time" column of the table, record the time you obtained, and also the time intervals obtained by other members of the class who used different concentrations. Calculations Find the fractional part of the reaction that took place per second (speed of reaction) by calculating the value of reciprocal time (1/sec) to the nearest thousandth (0.001) for each set of conditions. Questions and Conclusions (1) Make a graph by plotting concentrations of potassium iodate on the abscissa (horizontal axis) and the speeds of re- action as ordinates (vertical axis) . (2) State the conclusion that you reach as to the influence of change in concentration on the speed of a reaction. (3) Name the general principle which is related to your con- clusion. (4) In order for two molecules to react, what must be their position in space in relation to each other? (5) Assume that the automobile collision rate in cities is greater than that in rural areas. Account for the difference in rates. 100 (6) In view of your answers to (4) and (5), account for the fact that an increase in the concentration of one of the reacting materials causes an increase in the rate of the reaction. Optional Questions (7) From the shape of the graph in your answer to Question 1, write an equation relating the speed of reaction (S) to the concentration of iodic acid (C). (8) If two moles of iodic acid rather than one had been in- volved in the reaction, how would the mathematical equation in Question 6 read? Explain. (9) If doubling the concentration of a reactant produced an 8-fold increase in speed, how many moles of the reactant were involved in the reaction? Practical Applications (a) Why is compressed oxygen rather than compressed air used in welding and cutting torches? (b) Why are the clay and limestone, used in making cement, ground very fine before they are heated in a kiln? CONTINUOUS CLOUD CHAMBER Purpose. To set up a simple cloud chamber in which radiation tracks may be observed. Materials. A screw-cap jar, about 3 by 3 inches. Black felt. An illuminator capable of providing a bright parallel beam (optical disk illuminator) . About 15 inches of iron wire such as that used for baling newspaper. Methyl alcohol. A cake of dry ice, 5 pounds or larger. Method. 1. Carefully cut a circle of the black felt to fit snugly in the cap of the jar. 2. Cut another circle of felt to be placed at the bottom of the inside of the jar. This piece need not be black. 3. Since the jar will be used in an inverted position, fashion a retainer from the iron wire. Shape it so that its elasticity will hold it against the inside of the glass. 4. Pour enough of the alcohol into the jar to saturate fully both felts. It is wise to add a little excess. *From "Laboratory Experiments with Radioisotopes for High School Science Demonstrations." 101 5. Tighten the cap and set the jar, cap down, on the cake of dry ice. Results. Precipitation can be observed almost immediately. Ad- just the spotlight to a sloping angle and look through the side of the jar down through the beam of light. (If a gamma source is brought near the jar or if the heat of the hand is applied to the top of the chamber, the size of the drops will increase and there will appear to be more precipitation.) After approximately 15 minutes, when conditions will have become stabilized, watch carefully against the dark background ; cloud tracks appearing one at a time at uneven intervals of time will be seen. They can be observed best from an angle not too wide from the direction of the spotlight. The dry ice will last a long time if it is insulated with corru- gated paper or with several thicknesses of newspaper. Discussion. Sufficient time must be allowed for the entire system to come to a state of equilibrium. If a gamma source is brought to the side of the jar, many tracks will be observed inside the jar. HOW BIG IS A MOLECULE?* Materials: dilute acetone solutions of stearic and palmitic acids, a Hydrophil Balance or a rectangular trough, talc, and a meter stick. The Problem of Measuring Minute Distances Molecules are so very small that an attempt to measure their size is a real test of man's ingenuity. For example, a molecular weight of benzene (CoH 6 ) occupies about 90 cubic centimeters. This volume is shared by 6.02xl0- 3 (602,000,000,000,000,000,- 000,000) molecules, so that each molecule can occupy only 1.5xl0^ 2 - cubis centimeters. We conclude that a benzene mole- cule must measure only 5xl0 _s (0.00000005) cm. on a side. If we could place a yardstick beside a benzene molecule, and by some magical means make both of them grow at the same rate until the benzene molecule were as large as a baseball, the yard- stick would reach nearly to the moon — and be much too long for measuring baseballs. ■ ^Laboratory Conference for Teachers of Science and Mathematics, Duke University, Chemistry Division, July 20-24, 1953. 102 One solution to this problem is to find a "yardstick" of much smaller dimensions. The wave length of X-rays is about 10~ 8 cm., so we might suppose that this could serve as a "micro yardstick" to measure molecular distances. This is indeed the case, and much of our knowledge of molecular dimensions has resulted from the development of X-ray techniques. However, such equip- ment is expensive, and further ingenuity enables us to use a less costly method. Although one molecule is much too small to measure using a yardstick, if enough molecules were placed end to end, we could conceivably make a line long enough to measure. In order to make this method practical, we must find a way to align a large number of molecules in a regular fashion. A long-chain hydrocarbon molecule, for example hexadecane, Ci 6 H 34 , is insoluble in polar solvents such as water. On the other hand, the polar carboxyl group (— COOH) in acetic acid, CH3COIG, renders it soluble in water. A molecule of stearic acid, CH 3 (CH 2 ) 16COOH, can be thought of as resulting from the union of hexadecane and acetic acid. From our point of view this is a propitious combination which can be taken advantage of to ob- tain an alignment of molecules. For if we drop molecules of stearic acid onto a surface of water, they do not remain in a tangled heap, but instead arrange themselves so that the polar — COOH group can dissolve in the water, having the long hydro- carbon tail sticking upright out of the water. In this way stearic acid forms a film one molecule thick on the surface of the water, and the molecules comprising the film are oriented. If we confine a known number of these upright molecules to a regular area, and divide the measured area by the number of molecules, we can obtain the area of a single molecule. We therefore have a simple and inexpensive method for meas- urement of the exceedingly small dimensions of actual molecules by means of monomolecular films. This method has been used to estimate the molecular weights of some organic molecules, and to decide between possible structures of certain of the sterols, such as estriol, cholesterol, ergosterol, etc. It has also been de- veloped as a microanalytical tool for the determination of the fat content of red blood corpuscles, only 0.0001 gram of material being required for this determination. Experimental Procedure The Hydrophil Balance to be used in this determination is an 103 instrument designed for the accurate measurement of mono- molecular film areas under different tensions. A film behaves like a two-dimensional fluid. The volume of a given amount of gas varies inversely with applied pressure, but the area of a film varies inversely as the applied tension. Description of the Balance. The balance consists of a bronz tray 65 x 14 cm. At one end is a mica float attached to a fragile torsional device for measuring film tensions. A metal barrier can be moved along the trough, and the distance between this barrier and the mica float can be read from the metric scale along the side of the tray. The tray and barrier are heavily coated with paraffin. Make sure that the mica float and the platinum ribbons holding the float are not moved violently. Do not touch with your fingers any part of the balance which comes in contact with the film. Method of Measurement. Fill the trough with distilled water until the meniscus rises to the edge of the trough. Using forceps, carefully center the mica float between the protruding knobs (these correspond to zero on the metric scale). Place the moveable metal barrier at the 50 cm. mark. Zero the pointer by means of the knob at the rear. Using a 2 ml. pipet, drop about 0.5 ml. of the organic acid solution onto the surface of the water. Wait 30 seconds for the solvent to evaporate, then adjust the torsion knob to bring the pointer to its zero position and read the tension on the circular dial. Move the barrier a short distance in toward the float, zero the pointer, and take a second reading from the circular dial. Repeat until the film tension reaches 120. Calculations. Plot film tension against length. Extrapolate the straight, steep portion of the curve to zero pressure. The intercept on the length axis permits circulation of the area when a close- packed, monomolecular film is just formed. We will measure the dimensions of the molecules listed in the following table : Solution Molecular Density Concentration Acid Formula Weight 25° (grans/cm s ) stearic CH 3 (CH 2 ) 16 COOH 284.5 .850 1.82x10— 4 oleic CH 3 (CH 2 ) 7 CH=CH (CH 2 ) 7 COOH 282.5 .890 1.31x10— 4 The trough is 14 cm long. One gram molecular weight (one mole) is 6.02 x 10 23 molecules. 104 Sample Calculation for Stearic Acid a) Data: length of film =32.5 cm area of film = 14 cm x 32.5 cm = 455 cm- volume of solution = 0.50 cm' 1 concentration of solution = 1.82 x 10 4 g/cm 3 b) Calculation of molecular cross-sectional area: 1.82 x 10 ~ 4 (g,cm :! ) x (1/2) (cm 3 ) number of molecules = 284.5 (g/mole) ( molecules ) X 6.02 x 10 23 = 1-93 x 10 1T molecules in film ( mole ) 455 cm 2 00 a 1A 16 ( molecule ) area per molecule = = 23. b x 10 10 - . — 1.93 x 10 17 ( cm J ) c) Calculation of the length of the molecule: The density of stearic acid at 25° C is O.850 g/cm 3 . 1.82 x 10- 4 (g/cm 3 ) x 1/2 (cm :; ) Volume of stearic acid = = 0.850 (g cnf) 1.07 x 10- 4 cm 3 1.07 x 10- 4 cm- Length of a molecule = = 23.5 x 10- s cm 455 cm 2 One Angstrom unit (A) is 10~ s cm, so for stearic acid we find: area of a molecule = 23.6 sq. A length of a molecule = 23.5 A number of carbon atoms — 18 length per carbon atom = 1.3 A A Simpler Method Yielding Approximate Molecular Dimensions The measurements may be made more simply though more approximately by the following procedure : Replace the Hydro- phil Balance by any rectangular trough. Place a meter stick so that its zero is at a mica float or one end of the trough. This will be one barrier. Fill the trough as before, and sprinkle talc across the width of the trough at the 30 cm mark to form a barrier. Drop o.5 ml of solution upon the water between the mica float or the end of the trough and the talc barrier. The talc will move down the trough as the acid spreads, until the 105 acid forms a film which is approximately monomolecular. Meas- ure the distance between the mica float or the end of the trough and the talc barrier and perform the calculations just as before. Since the tension will not be exactly that required to form a close-packed monomolecular film, the dimensions calculated by this method will be in error by 10-15%. References. 1. E. Mack and W. G. France, A Laboratory Manual of Ele- mentary Physical Chemistry, D. Van Nostrand Co., New York (1934) 2. "Determination of Monolayers and Duplex Films," by W. D. Harkins, p. 486 in Physical Methods of Organic Chemistry, Interscience Publishers, Inc., New York (1949). 106 AND TtUHIHUUta (MMTTOttf CHAPTER 4— SCIENCE PROJECTS AND SCIENCE FAIRS Science Projects • Different Methods ° Some Questions • What Can Be Done • Choosing Topics • Individual or Group Responsibility At School or at Home • How to Get Ideas c Choosing a Problem • Classification of Problems • Sources of Ideas Science Fairs • Steps in Developing Exhibits • Basic Considerations 9 Other Competitions 107 Science Projects and Science Fairs SCIENCE PROJECTS Different Methods When a teacher takes a critical look at the problems involved in teaching a group of students in science for 180 days, he will come quickly to the conclusion that no one method will suffice for each of these days. Different portions of the science work will call for different techniques, the problems raised by the students and the interest of the students will cause a change in the methods of working, and the background of the teacher will make it necessary to develop various approaches. Whatever the situation may be at various times of the year, the teacher will find it necessary to do project work to a lesser or greater degree. It might be well to change the word "project" to "junior research work", if the proper emphasis is to be given to this method of learning. When this is done, then every student, according to his ability and background, can do some of the things which scien- tists do — discover new facts, relationships, concepts, etc. In short, he can become a junior scientist, even if his results are not of the highest order. What he discovers might be something that many people have known for a long time — but it is a new dis- covery for him. Or he might uncover a fact in nature that few have ever observed. Whatever the work might be, it should be done in an atmosphere of pioneering, exploring, and adventuring. If this is the feeling which has been developed, then the students will put forth energy into activities which will prove to be profit- able. Some Questions There are a number of questions concerning "junior research work" which might arise with science teachers. Some of these might be: How can I get my students interested in doing junior research work? Should I require every student to do at least several projects during the year? Should I assign topics to the students? How can I supervise project work being done by 100 different students ? How can I evaluate the work of the students ? Where should be work be carried on ? Should the student be per- mitted to go to his parents or to resource people in the community for help? How do I arrange to exhibit in a science fair? What value is there for a student to compete in a science fair ? How do 108 students feel about entering exhibits in a science fair? How can I give a complete science course and in addition have my students participate in these various activities? Where can I find sugges- tions for junior research work? As one can easily see, there are no good answers for some of these questions. Solutions of these problems will vary consider- ably from one group of students to another and from one teacher to another. For some teachers this type of work might occupy a considerable part of the time, while for others it will be much less. This is as it should be. Teachers differ greatly in their back- grounds in science, in their personalities, and in their most ef- fective ways of working with boys and girls. But whatever the situation might be, all students should have some opportunity to approach their science course from the standpoint of junior research work. What is meant by a "scientific project" or "junior research work"? In the publication, // You Want To Do A Project, Wash- ington, D. C, National Science Teachers Association, 1954, page 3, which was written for the high school student but which con- tains information important to the teacher, there is this discus- sion: "Let's see if you know for sure what a science project is. Among practicing scientists a project is simply a study of some- thing — what it is and how it happened, is happening or might be made to happen. Is this also true for student projects? Why not? Wouldn't it be interesting to study something that puzzles you, or prove something for yourself, or make something happen that you would like to have happen? "And don't overlook something else. There are other ways to get on the science team. People are needed who like to collect and classify things. Scientists need instruments, designers and equipment builders. Someone has to care for laboratory animals and plants. There is a need for men and women who can work in libraries and prepare summaries of previous works. Reports have to be written and illustrated. These science-related skills can suggest good projects. Be sure, however, that you show how your work fits into a study of something — what it is, how it hap- pened, is happening, or might be made to happen. The satisfac- tions that come from discovering an invention make our Madam Curies, our Pasteurs, and our Wright Brothers". An approach from a different angle to the question of what is a project is given in the book, How To Do An Experiment, by 109 Philip Goldstein, Harcourt Brace & Co., New York, 1957, page 56. "Now you want to know what a project is. Does it mean something big? Well, not necessarily. Does it mean something new? No, not necessarily. Does it mean an experiment? No, not necessarily. It might mean all of these; and yet, on the other hand, it need not mean any of them. When we speak of a project we mean something that you do; something you design; some- thing that you make or build in contrast to something that you read about, or something that you study, or something that you buy." From the above discussion, one can readily see that if a stu- dent is to come forth with a worthwhile project, he should have in mind an important question for which he desires to get a good answer ; or he will suddenly realize that he is faced with a prob- lem for which he earnestly desires a solution; or his attention and interest will be focused on a science concept concerning which he wishes to clarify his thinking. When the student is placed in either one of the above positions, encouragement on the part of the teacher should cause him to do the necessary work (reading, thinking, experimenting, consulting with authori- ties, etc.) to keep his interest alive and to get a satisfactory an- swer or solution. This work might keep him busily engaged for one or two days, for a week, or for several months. For this to happen, though, it generally is essential that the student feel that the problem is one that has arisen from his own observa- tions and thinking, and not one that the teacher assigned him. In reality it might be a teacher-inspired problem, but it was handled in such a manner that the student felt that it was actu- ally his. To make this happen requires a great deal of skill, knowledge, and ingenuity on the part of the teacher. What Can Be Done What can be done to initiate junior research work on the part of one or more of the students in a science class ? Profitable sug- gestions on this are contained in ' 'Science Projects as Stepping Stones to Careers in Science," Washington, D. C, The Science Teacher, November, 1956, pages 339-343. In this article the fol- lowing recommendations are made: "1. If the teacher can spend time talking to the students as opposed to 'lecturing science' this more personal approach no will help the student become aware of the new problems which exist about him. 2. Every science teacher should have a research project of his own to interest students and show them problem solving techniques by precept and example. This will also lift the science teaching profession in the eyes of scien- tists and the community. 3. Students and teachers should make periodic trips to in- dustry and research laboratories to visit with scientists, see actual projects under way, and get ideas for new and practical projects of their own. 4. Science teachers should be diplomatically aggressive in enlisting advisory consultants from industrial laborato- ries to assist the gifted science student in problem solving experiences through projects. 5. Science teachers can be instrumental in increasing the number of traveling science demonstrations by testifying as to their effectiveness and requesting that such lectures be presented in their schools. This can sometimes be ac- complished by the science teachers consenting to be placed on the school's assembly committee as an advisor or con- sultant. 6. Students should be encouraged to start projects early if they are to be submitted in any recognition program. Seasonal projects must be planned well in advance if they are to be part of the class work. 7. The science teacher will find it helpful to maintain a per- sonal file on projects. Such a file should include articles which stimulate project work such as brief descriptions of projects, awards, science fairs, achievement programs, junior academies of science, and science congresses. 8. Science teachers should modify their methods of evaluat- ing a student's progress in the light of all objectives of science teaching and should give particular attention to the contributions of projects." Choosing Topics Some students will be discouraged in initiating a project if the only material presented to them is that which deals with topics of prize winning exhibits of science at science fairs. This may ill cause them to think that only gifted students can do a worth- while project. Such a feeling should not be generated in a class because this technique can be used successfully by students hav- ing varying abilities. This is one of the distinct advantages of encouraging project work part of the time — the slow as well as the rapid learner can participate in project work, whereas this technique cannot be used too successfully in other types of scien- tific work. The key to success is to cause the slower learning students to raise some simple questions which might be answered in a relatively short time, while the rapid learners are encouraged to tackle difficult problems which might take much effort and long periods of time to solve. For example, one student became interested because of the teacher's comments and questions on the effects which can be observed by sprouting and growing corn in four different types of soil; another student decided to find out the rate of leaching of phosphorus and potassium in different types of soil under varying conditions. One of these projects was rather simple and required no great amount of study and reflec- tive thinking whereas the other had many aspects that could be explored and required a lot of planning and research on the part of the student. In many high school science classes, the complex- ity of the project will vary from that which could be done nor- mally in the upper elementary grades to that which would be done on the college level. This is the distinct advantage for which the teacher should look — a type of question which can be raised in a class and for which an answer can be found on several levels of ability. Thus individual differences of students can be used to encourage rather than discourage junior research work. Individual or Group Responsibility The question commonly arises as to whether an individual student should be entirely responsible for a project or whether he should work at times with one or two other students. Evidence shows that students should work in both manners — individually and in small groups. Use of the group method as a problem solv- ing technique allows greater insight into the problem. In college research, the chemist, biologist, biochemist, physicist and statis- tician all work on a common problem. Presentation of this tech- nique of knowledge-sharing can begin at lower levels. In line with this approach, the teacher should organize the entire class as a team to tackle some of the important problems that arise in the 112 class during the year. When this is done there will be several sub-teams composed of two or three persons. For example, the class might become interested in making a survey of the flora in the local school community in order to answer questions raised about the habitat of various species of plants. To obtain the necessary distribution data might require the work of the whole class, or this might be done better by using sub-teams to be re- sponsible for specific aspects of the problem. At School or at Home Since this raises a problem of whether the project work should be done at school, after school hours, or both, what decision should the teacher make? It is obvious that the student must work at school and at home to collect the necessary data. In gen- eral, project work involves an extended learning situation and this of necessity forces the student to work on his project after school hours. This is good because it is an objective for which teachers are striving in their science classes — to keep curiosity alive and thus motivate the student to pursue the learning of science, not only during the 180 days of school but also the entire year. For example, it is desirable that some students become so interested in a research project that they will work on it during the summer months. A student might become interested in why his father purchases new hybrid corn seed every year — why does he not use his own seed? The student can set up an inter- esting research project during the summer and try to get an answer to some of his questions. He might decide to plant six short rows of corn, using his own seed, and six rows of the same length, using new hybrid seed. He will keep an exact record (written, photographic, etc.) of what happens to each seed that he plants. In the fall he can share his results with all students taking biology. Obviously, this work must be done out-of-school hours and even during the summer months. But the planning for this work should have been done in school in close consultation with the teacher and through conferences with scientifically trained personnel in the community. How to Get Ideas The science teacher will discover in his science classes some students who have never participated in real project work. Sci- ence for these students has been a "read-about, talk-about" ex- 113 perience. They have never experienced the thrill of a scientific investigation. Generally, these students will have few ideas. How can a student go about getting an idea for a project, a junior research problem, or an investigation? Little progress will be made if the student is advised to sit in a chair for an hour and try to dream up a problem on which he thinks he would like to work. The following helpful advice is given in the book, How To Do An Experiment, Goldstein, Harcourt Brace and Co., New York, 1957, page 64. "Rather, the best problems arise of their own accord as a result of something you read, or something you do, or something you see. Things are going on all around you. Significant events are taking place all the time. People are doing things ; you are seeing things ; hearing things. If you keep your eyes and ears open, and your mind alert, you are sure to run into many situations which puzzle you. Any one of these puzzling situations might be the basis of a research problem'*. Choosing a Problem In this same publication which was written for the junior and senior high school student, the teacher will find a number of sug- gestions on choosing a problem: "1. SELECT A PROBLEM WHICH DEALS WITH SOME- THING OF INTEREST TO YOU. If your favorite hobby is raising tropical fish, find a problem for investigation which deals with tropical fish. 2. SELECT A PROBLEM IN A FIELD WITH WHICH YOUR ADVISOR IS FAMILIAR. If your advisor is an expert on protozoa, he can probably give you more help with a problem on protozoa than with a problem on as- tronomy. 3. SELECT A PROBLEM WHICH IS APPROPRIATE TO THE PURPOSE WHICH YOU HAVE IN MIND. If you are doing it to make a report for your science class, it may be enough to do some extensive reading, summarize what you have read, and make the report. By contrast, if you are carrying out an investigation to fulfill the require- ments of a science scholarship competition, you must be sure that the problem you select meets the requirements set down in the rules. 114 4. SELECT A PROBLEM WITH WHICH YOU HAVE A GOOD CHANCE OF ACCOMPLISHING SOMETHING. It is not always easy to determine in advance that working with a certain problem will lead to a conclusion, but there are several things to keep in mind which can help you to eliminate projects that are sure to go uncompleted. a. Will you be able to finish your investigation in the time you have at your disposal? b. Can this investigation be carried out with the phys- ical facilities available to you? c. Do you have the necessary knowledge to carry out this particular investigation? d. Do you have the technical skills necessary to carry out this project? e. Does the investigation you are considering have any dangerous aspects? f. Is the investigation you are considering worth- while?" Classification of Problems To assist students in this important initial step the following classification of problems is given: 1. Problems of Historic Nature. Under this heading might fall any activity which repeats a famous experi- ment originally carried out by a scientist of the past, or the building of a model of some famous piece of equipment which was used by a scientific worker of the past. ... A few examples are: a. Inheritance in peas ; an experimental re-examina- tion of Mendel's work. . . . b. Constructing a Leeuwenhoek microscope. . . . c. Archimedes' principle rediscovered. d. The development of lighter than air craft. 2. Making A Collection. To be of any value, from the point of view of science, a collection must be so arranged and organized that it tells a story — a story of scientific interest and value. Here are a few examples: a. A collection of seeds around the school. . . . b. What can we find at low tide? c. A collection of giant crystals grown from solution. d. My seaweed collection. e. Humor in science — a collection of cartoons. 115 Designing And Building A Piece of Apparatus or Equipment. The thing you are building might be as simple as a water wheel or as complex as a Tesla coil or a cloud chamber. Whatever it is, it must work. Here are a few examples : a. A working model of a subsonic wind tunnel. . . . b. A continuous cloud chamber. . . . c. High temperature experiments with a home made electric furnace. . . . d. The construction of a six inch Newtonian reflect- ing telescope. . . . e. A working model of a volcano. . . . Testing or Standardizing a Product. . . . Here is ma- terial for unlimited research. Consider these investiga- tions which have already been tried by others: a. Does monosodium glutamate actually improve the taste of food? b. Do toothpastes kill mouth bacteria? . . . c. Testing the effectiveness of four different insecti- cides against the common house fly. . . . d. A comparison of the vitamin C content of Florida and California oranges at different seasons of the year. . . . e. Budding in yeast as affected by the amount of sugar in solution. Developing A New Product or A New Use For An Existing Product. . . . Perhaps you too can seek a new product, or a new use for one that is familiar. Other pupils have done so. Here are a few illustrations: a. A new type of space station. . . . b. Producing seedless tomatoes by treatment with plant hormones. . . . c. The use of red cabbage juice and grape juice as indicators. . . . d. Hydrolysis of wood into fermentable sugars. Finding a New or Better Technique for Accom- plishing Something. . . . Perhaps you can find a better way of doing something It is possible. Here is evidence in the titles of several student investigations of this type : a. Injecting fertilizers instead of putting them into the soil. 116 b. Using paper chromotography to identify amino acids. . . . c. Stimulating plant growth with vitamins and antibiotics. . . . d. Pictures in poor light with hypersensitization. e. Dwarfing garden plants with chemicals. . . . 7. Describing A Natural Phenomenon. . . . There is still much work to be done in observing nature or in describing the natural phenomena that are always about us. Many of our fellow students have done interesting work with this sort of activity, as the following titles show : a. Studying the sun spots on the sun. . . . b. A study of extrasensory perception. . . . c. The effect of overcrowding on the growth and re- production of fish. . . . d. Regeneration in planaria. . . . e. The twenty-one day miracle — chick embryology. 8. Demonstrating A Scientific Principle In Action. ... It takes only a little imagination to go from the basic idea to a problem which arises out of it. From there it is only a step further to a project, experiment, or other observation. Here are some examples : a. The mechanism of muscle action. b. Illustration and proof of the laws of motion. c. The study of crystallography. d. Determining the growth curve of guppies. . . . 9. Relating A Scientific Principle To Everyday Life. . . . Many problems originate from attempts to apply the principles to worldly matters, and each problem that arises can be the beginning of a project, an experiment, an investigation, or research which will lead you into new and more interesting fields. Here are a few examples : a. Retarding spoilage in apples. . . . b. The absorption characteristic of filters of five dif- ferent brands of cigarettes. . . . c. An experiment in the elimination of crab grass. . . . d. How the doctor uses blood to diagnose disease. 10. Broad Surveys. Some projects and investigations do not fit into any of the previous categories. They are broad 117 surveys, covering wide areas of scientific knowledge. Here are a few examples : a. An evaluation of food advertising. . . . b. Soil erosion in the United States. c. The use of fingerprints in identification. . . . d. The production of silver mirrors. e. Indian relics tell a story. f. Hydroponics. Sources of Ideas There are many sources of ideas for science projects. One of these publications is Thousands of Science Projects by M. E. Patterson and J. H. Kraus, Science Service, 1719 N. Street, N.W., Washington 6, D. C, 1953. 25c. Other excellent sources of ideas are the various publications of the National Science Teachers Association, 1201 16 St., N.W., Washington 6, D. C. These pub- lications are Science Teaching Ideas II, price $1.00; Star Ideas in Science Teaching, Price $1.00 ; Encouraging Future Scientists; Student Projects, Price .50 ; // You Want To Do A Science Project, Price .50 and the back issues of The Science Teacher, yearly subscription $6.00. In the November, 1956, issue of The Science Teacher, pages 344-351, these ideas for science projects are given. Under each there are suggestions for carrying the project to a successful conclusion : 1. Pollen Analysis and Detection of Allergens 2. Biochemical Pollen Research 3. Production of Plant Mutations by Colchicine 4. Effects of Stream Pollutants on Life in the Stream 5. Legumes and Nitrogen Fixing Bacteria 6. Radioisotopes 7. Demonstration That Protozoa Live Within The In- testines of A Termite 8. Regenerative Powers of The Earth Worm 9. The Effect of Testosterone on The Comb Growth in Chickens 10. Virus in Cigarettes 11. Service Sterilization of Food by X-Rays 118 12. The Ability of Wood To Withstand Stresses 13. Relation Between Mineral Content of Soil and Mineral Content of Plants Grown In It. 14. Radioisotope Tracers. 15. Comparison of Nervous Systems of Animals With Contrasting Metabolic Rates 16. A Study of The Digestibility of A Cereal as Meas- ured By Rats 17. Flatworm Parisites 18. Use of Serology To Establish Relationships Among Insects 19. The Construction, Calibration, And Use of A Therm- ocouple in Determination of The Melting Points of Various Metals 20. What is The Rate At Which Sodium Nitrate Leaves The Top Foot of Soil? 21. Detecting Earthquakes By Homemade Seismograph 22. Permanent or Semi-Permanent Slide Collection of Gross Structures 23. Controlling Germination Time of Seeds 24. Photomicrography — A Tool For The Student Science Project 25. Comparative Vertebrate Skeletons 26. Cancer Produced By Virus 27. Determination of The Glycogen of The Liver of Hibernating Animals 28. The Study of Mendelian Laws Using Drosophila 29. Determination of The Relative Amounts of Con- stituants of wool 30. An Investigation of Metallography 31. Preparation And Liquefaction of Gases 32. Physical Changes Which Occur During Dehydration of Foods SCIENCE FAIRS In the spring of 1957 the headlines in one paper were "Science Fair Exhibit Draws Large Crowd — Five Thousand Persons Pack Community Center Gym". When this number of school pupils, educators, parents and interested persons go to a science fair, 119 there must be value in such an educational project. It indicates that people are interested in watching students compete scholasti- cally as well as athletically. If students and parents feel that this sort of competition is valuable, then students should have this opportunity. To provide this opportunity, students, teachers, administrators and parents must know the problems to be solved in order to have scientific exhibits and successful science fairs. Steps in Developing Exhibits The first step in developing good exhibits is to have good project work as a part of the learning experience in science classes. Little of real educational value will be observed if pri- mary emphasis is placed on something to put in a science fair. Teachers and students should realize that scientific investigation, even on an elementary level, is a fundamental reason for en- couraging students to enter an exhibit on a competitive basis. Presumably, then, any student exhibit will be the result of a scientific interest or curiosity, and will not be simply obeying the command of the teacher to have an exhibit ready on a cer- tain day. Is there a difference in a project that is prepared by a student in a science class and homework and in an exhibit for a science fair? They might be the same, but usually there is a difference. This is pointed out clearly in the article "Fitting Science Fair Activities into the Total Academic Program" by John Read, The High School Journal, University of North Carolina Press, February 1956, page 283, in which he says : "Essentially, the project or exhibit is a communication. A pupil has an idea, from which comes an invention. It must be put into language which everyone can read. People in great numbers will pass the exhibit quickly. Judges will stop a little longer. But the message must be clear. 'I thought on this, and I wanted to tell you about it'. This is also the problem of modern advertising". In other words, the exhibit must "talk" to a group of persons looking at the exhibit and to a group of experts who have been assigned the duty of evaluating the exhibit on the basis of certain predeter- mined standards. In the book How To Do An Experiment by Philip Goldstein, Harcourt Brace & Co., New York, 1957, pages 60-63, there are ten suggestions which students should consider if they desire 120 to turn a science project into a science fair exhibit which will compete well with the other exhibits. These suggestions are : 1. Is Your Project A "Crowd Stopper"? ... If you don't want it to be overlooked in the crowd, you must do some- thing to make people notice it. What can you do? Color is one idea ; color attracts people. Making something with working parts is another ; people like to push buttons and operate things. . . . 2. Is Your Project Attractive? Once you have stopped the crowd, will they continue to look, or will they turn away with the comment, "What a sloppy job!" 3. Does Your Project Have An Interesting, Attractive Title? Just as the headline on a newspaper article is intended to draw your interest, and make you want to read the article, so the title of your project should attract spectators. . . . 4. Does Your Project Tell A Story? . . . One simple idea, clearly demonstrated, is far better than many ideas rolled up into a confusing package. 5. Does The Story Which Your Project Tells Illus- trate A Scientific Principle Or A Scientific Fact? Remember this is a science fair, and that any project presented here must have some relation to science. 6. Is Your Science Fact 03. Principle Presented Ac- curately? The most attractive project in the world is a waste of time if the information it gives is inaccu- rate. . . . 7. Is Your Project Presented In An Original Way? . . . A novel twist, a new approach, calls attention to your own ability and thus makes a better project. 8. Is Your Project Well Constructed? . . . Will it be a simple task for you to set it up at the fair? Will it fit the space allotted to you? Will the exhibit stand up for the duration of the fair? 9. Does Your Project Require Special Care? ... If you have living animals, will they be fed and cleaned at the correct time? . . . Will your plants be watered regularly, or will they be allowed to wilt and droop? . . . 10. Does Your Project Meet The Conditions Specified By The Directors of The Science Fair? . . . 121 a. The exhibit should illustrate some aspect of pure or applied science. . . . b. Uniqueness of concept — the ideas should be orig- inal, in keeping with the age level of the exhibitor. Basic Considerations Assuming that the science teacher, students and principal of the school want to set up a science fair, what are some of the things that will need to be done? For any size school, the follow- ing are basic : 1. Decide Upon The Time For The Fair. Several factors will determine this period. Students should have been in a science course for more than a semester in order to have had the opportunity to do several good projects. If the students plan to enter exhibits in other fairs, such as county, district, state or national, then the local school fair must be held first. If the fair will be of such a size that it will require a large space for it, then the fair must be held when adequate space can be made available. Since the local school fair is for the benefit of the local students and parents, it might be wise to hold it when the P.T.A. has scheduled a meeting. 2. Decide Upon The Place. In small high schools, the fair can be held in the science department, but this will limit the time to an afternoon and evening. For a larger school the exhibits might be placed in a gymnasium or in a community center. Wherever it is held, a number of electrical outlets should be available. 3. What Kind of Awards Should Be Presented? A common award is an appropriate certificate, with colored ribbons to designate first, second and third place awards. If there are several high schools in an administrative unit and all plan to have science fairs, a quantity of attractive certificates can be printed at low cost. In general, cash awards are not recommended. 4. What Kind of Exhibit Space Should Be Provided? Tables that range in height from thirty inches to three feet and two to three feet in depth serve the purpose well. The moveable two-student science tables found in many science departments are good. If the fair is to be held off the school grounds, then tables or similar exhibit space 122 must be provided. Since enough space is difficult to pro- vide, limitations on the size of the exhibit must be set. A standard size is three feet deep (front to back) and four feet wide (side to side). For those exhibitors who desire it, 110 volt A. C. should be available. If several rows of tables are to be provided, try to keep at least eight to ten feet between them. Visitors to a fair want to look at exhibits in a leisurely manner and overcrowding pre- vents this. 5. How Can Exhibits Be Set Up With Little Confusion? A floor plan of the exhibit space should be made and each exhibit space numbered. Each student exhibitor is then given a number which designates the space allotted to him. This should be done several days ahead of time. Since many problems arise even with the best planning, the science teacher should consider himself as the Fair- master and be stationed at a particular place so that the exhibitors can locate him easily. For the many routine jobs, he should have several of his students, or parents, or fellow teachers to assist with these errands. 6. In What Manner Should The Exhibits Be Grouped? All that is important in this matter is to keep it simple — the fewer the classifications the better. Many fairs can operate on two basic classifications — biological science and physical science. Within these two classifications it might be necessary to have individual and group projects and junior high and senior high projects. 7. What Should Be Done About Publicity? The com- munity should know that the students are going to exhibit some of their science work. Many media of communica- tion should be used to do this. One school has the strong support of the merchants in the town and each year a display window is given over to the science department for two weeks preceding the fair. An attractive science exhibit is placed in the window and information on the fair is presented. Other schools use the newspapers and radio stations. Don't overlook the possibilities at school — arrange an attractive display on one of the bulletin boards in the corridors. If parents have been asked to help in the project work of their children, an invaluable source of publicity has been developed. 123 8. What Are The Responsibilities of The Judging Team? Effective evaluation of students' projects is a most im- portant job. Here is the place where much criticism arises. This criticism usually arises because the judging team does not examine the exhibits as thoroughly as it should ; it does not call in the exhibitors for consultation ; it gives recognition to too few exhibits; it does not have persons on it that have backgrounds in some of the science areas such as electronics; and it does not have a good under- standing of the reasons for the science fair and the nature of the program which produced the exhibits. These criti- cisms point up the fact that the schools should select the judges at least a month before the fair begins. During this time, the judges should hold one or more meetings when they will receive the information necessary in order to do a good job in evaluating the exhibits. This briefing- should include information on the science program, how the students prepared their exhibits, how many exhibits there will be, the arrangement of the exhibits in the exhibit hall, criteria for judging the exhibits, and the awards that are to be given. When the judging team begins its work, it should be furnished with some type of simple work sheet on which all the exhibits are listed by title and number. A minimum of two hours should be allowed for the judging. The students should be available for conferences when the judges need to talk to them. Before the judges leave, they should make a strong effort to talk with every exhibitor for several minutes. This points up the fact that the judging team has two impor- tant duties to perform : a. To judge the exhibits and make awards. b. To advise students how they can improve their exhibits. Other Competitions There are competitive programs for students other than science fairs. One of these, Science Achievement Awards for Students, is conducted by the Future Scientists of America Foundation of the National Science Teacher's Association. For 1958 this pro- gram offered one hundred and forty awards totalling $10,000. In 1957 more than 26,000 students participated in this activity. 124 Teachers find that this program affords many opportunities to encourage students to do science projects and to receive recog- nition and encouragement for the reporting of their accomplish- ments. Following are the basic items teachers need to know in order that their students may participate : 1. All students in grades 7-12 in public, private, and paro- chial schools in the United States, its territories, and Canada are eligible. 2. Projects may be done in any field of science or mathe- matics. 3. Projects may involve experimental studies, field studies, or other kinds of investigations similar to those carried on by practicing scientists. 4. Projects must be the work of individual students. 5. Students submit only reports of their projects ; they do not submit the actual projects themselves. 6. A completed entry requires submission of: a. A student data form b. A three-part entry form c. The project report, which may include drawings and photographs. 7. Entries may be mailed at any time but must be post- marked not later than March 15 of the year the competi- tion is held. 8. Equal numbers of awards are given in each of eight regions for students in each of three grade levels ; seventh and eighth grades, ninth and tenth grades, and eleventh and twelfth grades. 9. Projects which deal with metals and metallurgy are eligi- ble for regional awards and also for twenty special, national awards. Another of these competitive programs is the Science Talent Search for Westinghouse Science Scholarships. Not only is this a national competitive program but it is also a North Carolina program. Under the sponsorship of the North Carolina Academy of Science a State Science Talent Search is made. To make this State search a committee carefully studies all the entries made in the national program and selects those which it feels are worthy of recognition. Since all the entries must meet the re- quirements as set up for the national program, the following list of requirements for 1957-58 are given : 125 1. A completed science aptitude examination answer sheet, certified by student and teacher. 2. A personal data blank secondary school record, filled out by the student and by his teachers and principal. 3. A report of about 1000 words on "My Scientific Project" by the student. It should tell what the contestant is doing or plans to do in science in the way of experimentation or other research activity. It should be original, creative and interpretative in character. 4. Each contestant must take the Talent Science Search examination administered in the school on or after the first Monday of December. 5. All entries must reach the office of Science Clubs of America, 1719 N. St., N.W., Washington 6, D. C, not later than midnight, Friday, December 27, 1957. To compete in this program, the student must realize that he must give much time and thought to his scientific project. If he waits until the fall of his senior year to begin his work, his chance of completing a project which will receive recognition is small. All schools should study their students carefully and try to find science talent in the ninth grade. If this is done, then much help can be provided during the student's entire high school career. By the time he becomes a senior, he should have a project completed which will rank high in the eyes of the judges. A HIGH SCHOOL STUDENT TAKES A CRITICAL LOOK AT SCIENCE PROJECTS AND SCIENCE FAIRS* The first thing I wish to emphasize is that a science project teaches many lessons other than science. In fact, a science project carried to a successful conclusion teaches every attitude and skill that all other subjects teach. This type of project gives real meaning and purpose to other studies. For this reason, I would like to encourage every boy and girl from the first grade through the twelfth, to do science projects. When I was in the fourth grade my teacher (Mother) gave each student the picture of a butterfly to color in an art lesson. (Mother had bought the pictures and the directions for coloring them). The directions for coloring these pictures were not very clear. We could not follow them. Finally, Mother said for us to catch a butterfly at recess. What a time we had at recess! We did catch one, even though we had no equipment. When we got back to the room, we had no way to hold it so we could see its colors. That afternoon my parents and I went to Elkin to ask the druggist for something with which to kill butterflies. Since the druggist did not know what to use, he sent us to Len Hendren, the Elkin Postmaster, who is an entomologist. * Betty Lou Wallace, Eleventh Grade Student, Mountain Park High School, Surry County. 126 Mr. Hendren took my parents and me to his home where he showed vis a killing jar, a mounting board, a net for catching, and several cases in which he kept mounted insects. He also showed me books from which he found their scientific names. He volunteered to make me a net and a killing jar. A few days later he brought the jar, net, and books with colored pictures of many common insects. I took these to school where all the children in my room had great times catching any insect we could find. We searched the books until we found their pictures; we read all we could find about them. We wrote stories; we drew and colored their pictures. We found that some insects were helpful, whereas others were harmful. After school closed for the summer, I continued my interest in insects. I spent every possible minute in the daytime catching beautiful or odd insects. After supper I tried to find their names or mounted them on drying boards which Daddy had made for me. For many of my bugs I could not find pictures. Again I went to see Mr. Hendren. This time he arranged for me to get library books from the "Y" Library. Since we live 14 miles from Elkin, this arrangement was needed and appreciated. On this first visit to the library I got Holland's books, in which I found many listed, but not all. For further help Mother bought all the books we could find about bugs; still I could not find some of them. One thing that I did which was useful to me in my later work was to keep accurate data on each bug — where I found it and when I found it. I recall that two things happened which caused me to continue my hobby of collecting. One of the 4-H leaders heard about my bugs. He asked my father to make me two cases for my bugs in which to bring them to the county fair at Mt. Airy. How pleased 1 was! I rewrote all the names, dates, and places on one size paper (Larger than the bug). For this exhibit I got $4.00 — the very first money I had ever earned! Next, I was asked to come to the county 4-H meeting. At that meeting I was given an Entomology Medal and declared the County Champion. These two experiences made me work even harder ! By the next fall I had five cases of bugs. This time the Mt. Airy Fair gave me $25.00. I was really pleased! The Mountain Park Fair gave me $5.00. How I did work the next year! I had nine cases ready for the fairs that fall. I received the same awards again! That fall, after the local fairs were over, Dr. J. S. Dorton, Manager of the State Agricultural Fair in Raleigh, let me display them there. Dr. H. Eldon Scott, North Carolina Extension Entomologist, saw my display. After the Fair, he came to see us for the purpose of talking with us about my bugs. Dr. Scott was a great help, since he pointed out mistakes I had made and gave suggestions on correcting them. Mrs. Franklin, our elementary school supervisor, heard of the science fairs and told me about them. I took nine cases, which I had reworked, to the Science Fair at Woman's College, Greensboro. My display was called "Steps in Entomology". It was here that I faced a real problem — how to get nine cases in a 3' x 4' space. Daddy and Mother helped me work this out, Daddy being an excellent shop workman and Mother being good in organi- zation. Everyone who saw my bugs asked the same question: How did you catch them? How did you kill them? How did you get their wings to stay in place ? Where did you get their names ? How do you keep them ? These questions brought out my stfps: Catch, Kill, Mount, History, and Preserve. From working with that display, I learned that you should have a pur- pose, show how it is done, and then give the results. In all my work since that time, I have kept these three facts in mind, which I believe will be present in one way or another in all successful projects. When I was in the eighth grade I had the opportunity to compete in the State Science Fair held at Duke University. I was thrilled over the thought of going to Duke. My exhibit won Honorable Mention, which to me was wonderful, for I was competing with students from all the high schools in North Carolina. But the most important result of my experience at Duke was meeting Dr. Frank Mature, professor of entomology. He studied my collection very carefully and called attention to several good points in it. He invited Mother and me to see his collection. As soon as I saw his collection, I knew places where I could improve mine. I asked about the size of paper for the facts about the insects: he showed me the accepted size. I asked about how to write in small writing; he got out a croquill pen and showed me how. We compared names of insects. He showed me the latest books recognized as authorities — the judges had told me the books I had used were out of date but they did not tell me which ones to use. I asked him how to keep worms out of the bugs. He explained that most scientists used moth balls, but that they were not successful as I had found out. He then said that they had tried di-chloride moth nuggets which so far had proven successful. I shall always be grateful to Dr. Mature for he taught me quickly and kindly many of the things I wanted to know. He used terms I could under- stand. He demonstrated the small writing and then let me try to write. He gave suggestions on sources of materials. His interest and advice were most helpful to me in getting started. I came home from Duke University determined that my bugs would have the latest correct names, on the correct size of paper, written in small letters. My! the hours it took. I learned about orders, sex, stages, and so many other things as I studied. For more help on this work I obtained Dr. Alexander B. Klotts' book on butterflies. After studying it carefully, I wrote Dr. Klotts about the names 128 of some butterflies I had that were not in his book. He wrote me not to worry about the names, that if I got them in the correct orders, it would be enough for a young scientist. He suggested that rearing specimens was one of the best ways to get perfect ones. As a result of my previous work I learned how to recognize the sex of many insects and I observed that some of the insects laid eggs in the killing jar. This gave me an idea. Last year I kept the female moths until they laid their eggs, let them hatch, fed the larvae, watched them pupate, and finally emerge. I had 12 moths' eggs to hatch, nine of which went through all four stages. On every stage I kept accurate data. The time came to get ready for another science fair. I had so much material. What could I use? To get an idea I went back to the three points: purpose, material, and observations. Since a good project must teach one idea, why not do a project on Stages of Moths? My topic was settled, but how was I to get it displayed in an attractive manner in a 3' x 4' space? Past experience had taught me that every detail must emphasize the one thought. Pictures, posters, lettering, colors — everything must be done for only one purpose — emphasize the one thought. Since adult moths are colorful, I painted the plywood (light in weight and durable) with white enamel and the lettering was done with black enamel paint. The black on white makes the letters appear larger and gives a neat and simple background for the principle thought, which I was able to get over to the visitors. What does a science project carried out to a successful conclusion do for the student? It leads a student to read, spell, study art and practice art principles, and apply the fundamentals of arithemtic, especially fractions; to keep accurate records; to observe closely and learn how to express what he sees; to organize his materials; to choose words wisely; to work with others; and to listen intelligently to more experienced scientists. All of these are worthwhile and would be enough reason to have science projects, but there is another side which I think is very important. You meet many other boys and girls and men and women who are doing interesting and worthwhile things. These people understand your problems and joys of success. It is one of the best places to meet real friends. In every way I can think of science projects are helpful. I do not have words to describe the thrills I have had in winning at the science fairs! It is a big thrill to win in a local fair; but the district, State, and national competitions are really breathtaking! I like the way the leaders in the science fairs made every boy and girl who participated feel that they were winners. It was especially nice to hear Dr. Carroll say, "You have won first place over 45 to 50 thousand biology students in North Carolina." The trip to Los Angeles for the National Science Fair was so wonderful! I am still rejoicing over the unbelievable experiences connected with it. Mr. Joseph Krauss, Director of the National Science Fair had everything plan- ned to make each second count for the finalists in Los Angeles. All the tours were great — Disney Studios with the picture shows, picnic lunch, Marineland, North American Aviation, Inc., Pacific Semiconductors, Helms Bakeries, and the big banquets! Each one was a world in itself to me. All the people at each place made us feel they were highly honored by our visit and did their best to make it perfect. Besides all those wonderful experiences, I traveled there by airplane — a perfect trip from every point of view. The stay in southern California was worth all my hours of work. Since my brother lives there, he carried me to all the most interesting places in southern California, including deep sea fishing off the coast of Mexico, where I caught four big Yellow Tails, one 40 inches long. After these 19 days in southern California we returned by train, stopping in Houston, Texas, for three days. Finding enough time to do a good project is a big problem. It takes an unbelievable amount of time to do all the necessary experimenting and research and to check one's observations. When this is done, one must begin 129 to organize each detail before he can even start to put it in the final display form. Teachers should encourage each student to take one project and com- plete it just to have some understanding of the problems involved. All of the work on my project was clone out of school. Much of the actual experimenting was performed during the summer months. As I see it, if science projects are to be part of the science work of many students, time and materials will have to be provided at school. Many of the students will not be as fortunate as I in having a place to work and in having parents who were willing to assist with the details of turning a project into a science fair exhibit. More important is the fact that students need someone who shows an interest in their work and who will encourage them in their undertaking. The type of subject for these projects is important. I think it should be one that pertains to the local community, so that observations can be made easily. Students can find many questions that arise in their daily living for which they wish to obtain answers. For the past two years I have taught Science in the fifth grade under Mother's supervision. I find the best way to get children interested is to have them bring in something in which they are interested. Grasshoppers got us started on our first project. Other projects grew out of that study. One boy found a rock that interested him; an interesting new study started. For lack of simple materials not much was done by all the students, but one girl continued until her exhibit won in our local, and county science fairs and her exhibit looked good at the District Fair at Wake Forest College. This stimulation of her curiosity caused her to continue this study. One boy became interested in magnets and he, too, won in the local and county fairs, and went to the district fair. Three other girls followed the study of magnetism until they were able to have exhibits in the District Fair at Wake Forest College. I think the way our science fairs have been carried out has been wonder- ful. The cash prizes and trip were too great for words. Now that the trip is passed and the money spent I wish I might have had a certificate, a ribbon, or a medal, from the State Science Fair to show the visitors in our home. I believe all finalists would cherish some evidence of this kind as a momento of their experiences. My hope is that teachers will get their students so interested in science that they will venture into what is unknown to them and into work they will enjoy doing. When they have done this necessary work, then urge them to put it into an exhibit. It may not be perfect, but many lessons will be learned! 130 CHAPTER 5— SOME NORTH CAROLINA RESOURCES FOR TEACHING SCIENCE The Morehead Planetarium The Copernician Orrery The Morehead Planetarium Sundial N. C. State Museum Nuclear Energy • Nuclear Facts of Reactor Life • Atoms, Molecules, Bonds of Union • Forces, Electrical and Others • Components of Atoms: the Building Blocks of the Universe • Inside the Nucleus • Forces, Mass and Energy • Fusion: the H-Bomb • Fission: the A-Bomb • Fuel Supplies: Breeding • Fusion and Fission The Raleigh Reactor 131 Some North Carolina Resources for Teaching Science Quality science teaching implies effective use of available science resources. School science facilities go beyond the class- room and laboratory and include nearby streams and woodlands, water filtration plants, and other installations significant to science teaching. There are some very specialized science teach- ing facilities in North Carolina, however, which are not provided for each school ; but are so located as to be available to a large part of the school population. Some of these science facilities are described in this chapter in considerable detail because of their wide range of interest and depth of appeal. There are many other science facilities well worth visiting within easy driving range of most schools in the State. THE MOREHEAD PLANETARIUM "Never has a means of entertainment been provided which is so instructive as this, never one which is so fascinating, never one which has such general appeal. It is a school, a theater, a cinema in one : a schoolroom under the vault of heaven, a drama with the celestial bodies as actors." These were the words of Dr. E. Stromgren after he observed a planetarium perform- ance in 1925. Each year approximately 50,000 students visit the Morehead Planetarium at the University of North Carolina in Chapel Hill. The desire of those operating the Planetarium is that every student who visits it shall leave a performance with the feeling so well expressed above by Dr. Stromgren. If this is to be accom- plished, then each student should come to the Planetarium with some knowledge of how it works. As one enters the Planetarium chamber he finds himself in a circular room topped with a hemispherical dome made of per- forated stainless steel, which is 68 feet in diameter. Almost twenty million holes, three thirty-seconds of an inch in diameter, provide the acoustical treatment which, assisted by blankets of absorbing material hung behind the dome, make this chamber one of the finest auditoriums in the world. In the center of the chamber is the instrument which provided the changing picture of the heavens. It is sometimes called the 132 Planetarium Projector, or the Optical Planetarium, to suggest the manner in which it produces by projection by optical means a well-nigh perfect representation of nature's sky on the painted hemispherical screen which arches overhead. How is this accom- plished? Just what is the Planetarium Projector? An examination of the picture of the Optical Projector reminds one of a large gymnastic dumbbell — a bar with a weighted ball at each end. In this instance a single 1000 watt lamp of special make is set inside each of the large spheres at the end of the dumbbell-shaped portion of the instrument. Clustered about this lamp, in each ball, are 16 complete projectors, each of which shows a portion of the sky. These pictures are carefully fitted, with no gaps and no overlaps, so that the southern half of the heavens is projected from one star-ball, and the northern half from the other one. The star-field plate is a very thin bit of copper foil, sandwiched between pieces of thin glass. In the copper foil, only little more than half of a thousandth of an inch in thickness, holes are punched, in the correct position for the stars. For the faintest stars, the holes are a trifle less than a thousandth of an inch in diameter ; the largest stars are produced by holes about one thirty-second of an inch in diameter. In all, 65 different gradations of star brightness are shown, so 65 different sizes of punch are used. It is interesting to note that one star, Sirius, the brightest in the heavens, has a separate projector, because its punched hole would be so large that the disk of the star, as seen on the dome, would be awkwardly large. By using a separate projector with a smaller hole and a brighter lamp and optical system, the cor- rect appearance of the star among its neighbors is obtained. In addition to the projectors mentioned, there are projectors to show the network of positional circles in the heavens ; the celestial equator, the meridian-like hour circles, the parallels to the celestial equator, and the Sun's apparent path (called the ecliptic) , with the month-names and the days of the month indi- cated, so that the date may be read off by examining the position of the sun on the ecliptic. Another projector provides for the year to be projected on the sky at the touch of a switch. Another set of projectors, in small spheres set on the framework of the instrument, shows the celestial meridian which splits the sky into eastern and western halves. Another question will arise as to how the various motions are 132 obtained. Two motors drive the Planetarium Projector around a polar axis to stimulate the apparent motion of the sky pro- duced in nature by the diurnal rotation of the Earth. The motors are so geared and linked that a period of 24 hours may be com- pressed into any one of several periods, ranging from 10 minutes 30 seconds to only 48 seconds. Time may be made to pass, either forward or backward at these somewhat leisurely rates, merely by the operation of two switches. Another motor performs the task of turning the whole dumb- bell-structure around a horizontal east-west axis to simulate the changing appearance of the sky as the observer travels north- ward or southward. If the appropriate switch is operated, one may journey southward to the equator, into the southern hemi- sphere, across the south pole, up the other side of the world, across the equator into the northern hemisphere, then across the north pole and back home again, all in a trifle more than five minutes at a speed of about 5000 miles a minute. A fourth motor turns the instrument on its own axis to pro- duce the changes that occur as a result of the precession of the Earth's axis. The Earth spins as a great top and, like any top, as it spins the axis wobbles, pointing in all directions in a cone- shaped action. Because the Earth's spin is rather slow — once around in 24 hours — its wobble is also slow — once around in about 25,000 years. This cycle of 25,000 years can be traced out in the Planetarium in only a minute and a quarter. There are three other motors on the Planetarium Projector. These three provide for the annual motion, whereby the Sun, the Moon, and the planets Mercury, Venus, Mars, Jupiter and Saturn travel in synchronism against the background of the stars, at such rates that a year may be made to pass in any one of several periods from about three minutes to as little as five seconds. A visit to the Morehead Planetarium will show that no science is so favored as astronomy in the possession of such a magnifi- cent piece of demonstration apparatus. While it is a machine, the performance of the Planetarium is anything but mechanical. In describing the Adler Planetarium, the first in America, its first director, Dr. Philip Fox, concluded with these words : "The visitors come to see a stirring spectacle, the heavens brought within the confines of museum walls. Not a trivial plaything, a mimic aping firmament, but the heavens portrayed in great 134 dignity and splendor, dynamic, inspiring, in a way that dispels the mystery but retains the majesty". THE COPERNICIAN ORRERY Below the Memorial Rotunda of the Morehead Building is a circular room which houses the Copernician Orrery. It is given the name Copernician because it represents the system of the planets with the Sun in the center as urged by Nicolaus Corperni- cus. The name "orrery" has been given to the instrument because Charles Boyle, fourth Earl of Orrery, had one made for himself and Sir Richard Steele, editor and essayist, dubbed the instru- ment an "orrery". Many mechanical models of the motions of the planets have been worked out in the past ; today standard gears can be pur- chased which will provide the correct speeds. In the past these devices showed the planetary system as seen from the outside. In the present century, orreries large enough to permit the observer to get inside have been made. This is the type at the University of North Carolina. The size of the instrument can be clearly pictured since the orbit of Saturn, the outermost planet seen, is 35 feet in diameter. When one visits the Corpernician Orrery he can push a button and a program on tape will tell the story of the planets. At the same time he will see the planets moving around the Sun in circular paths, all located on the ceiling of the room. The time scale is such that a year is 12 minutes. The planet Mercury revolves around the Sun in about 3 minutes, the Earth rotates in only 2 seconds, the Moon revolves around the Earth in about a minute, while the planet Saturn needs almost six hours for one complete trip around the Sun. In addition to Earth's moon, the two swiftly moving satellites of Mars are shown, five of Jupiter's twelve, and five of Saturn's nine as well as the fantastic system of rings. It is possible to build the motions of the planets described above into the Planetarium Projector. This has been done at the Morehead Planetarium and thus one can have a complete picture of the heavens above from the one projector. Nevertheless it will be well for the students to visit the Copernician Orrery to clarify their concepts on the movements of the planetary system. Si V: THE MOREHEAD PLANETARIUM SUNDIAL "Behold, I will bring again the shadow of the degrees, which is gone down in the sundial of Ahaz, ten degrees backivard." Isaiah xxxviii 8 The SUNDIAL is an instrument for measuring time by means of the motion of the sun's shadow cast by a stile or gnomon. It is an instrument of great antiquity. The probable date of the sundial referred to in the Scriptures quoted above is about 700 B.C. "The earliest sundial of whose construction there is certain knowledge is the dial of Berossus, a Chaldean astronomer about 300 B.C. This dial was a hollow hemisphere set with a bead at the center. The arc was divided into 12 equal parts. The dial, as a consequence, divided the day from sunrise to sunset into 12 equal parts, which were called 'temporary hours'. The length of these hours necessarily varied with the seasons. "For 1700 years sundials, though built in various ways, were all based on the principle of temporary hours. Then about the year 1400, the introduction of clocks and other mechanical devices for measuring time made necessary the determination of equal hours. By the end of the sixteenth century the temporary hours seem to have gone out of use. Sundials by the eighteenth century were used very little, except as ornaments and relics. However, mathematicians with astronomical knowledge could compute a correction table (similar to the one utilized on the Morehead Planetarium Sundial) and give the exact number of minutes to be added, on any particular day of the year, to the sun-shadow's time to give the Local Mean Solar Time. "A sundial is composed of two parts, the dial face or plane and the stile or gnomon. The dial face is divided into quarters and the dial must be set so that the dividing lines run toward the four lines of the compass. The dial is further marked into hour spaces, with minute divisions. The gnomon is a flat piece of metal set in the center of the dial, and, in the Northern Hemis- phere pointing to the North Celestial Pole. On sundials used in the Southern Hemisphere the gnomon must point toward the South Celestial Pole. "Sundials are known as horizontal, vertical, or equinoctial, according as their planes are in the same plane as the horizon, 137 in a plane perpendicular to that plane, or parallel to the equator. The Morehead Planetarium Sundial is, of course, a horizontal sundial. "A night or nocturnal dial is an instrument showing the hours of the night by the shadow of the moon ; or the hour may be found by the moon's shadow on a sundial by observing the following rule: observe the hour pointed out by the moon's shadow, find the days of the moon's age in the calendar, and take three- fourths of that number to be added to the time shown by the shadow to give the hour of the night." Time Correction of a Sundial "Time of day is related to the position of the sun in the sky, whether above the horizon or below. More precisely, time of day is measured by the angular separation of the sun from the celes- tial meridian which is the great circle in the sky running from the North-point of the horizon, through the zenith to the South- point. Thus, when the sun is 15° past the meridian, the time by a sundial is 1 hour P.M., for since it takes the earth 24 hours to rotate 360° on its axis, it will rotate 15° in one hour. "The sun has two apparent motions in the sky: (1) The first is the diurnal east-to-west motion caused by the earth's rota- tion. Due to this motion alone, the sun moves 15° an hour across the sky as mentioned above. (2) At the same time the earth revolves about the sun taking a year to complete its period. This results in an apparent west-to-east motion of the sun rela- tive to the stars at the small rate of about 1° per day, an amount hardly perceptible. "The apparent path of the sun among the stars is called 'the ecliptic'. The ecliptic cuts the equator of the earth at an angle of 23V2°. This obliquity of the ecliptic is caused by the fact that as the earth revolves about the sun, its axis of rotation does not stand perpendicular to its orbit but tilts from the perpendicular by an angle of 23 ] /o°. If there were no obliquity, that is, if the earth's axis were perpendicular to its orbit, the sun would always be at the zenith somewhere on the earth's equator. As we all know, the obliquity results in a region 23 J /■>" on both sides of the equator called the Tropical Zone where it is possible for the sun to be overhead twice during the course of a year. "The motion of the sun along the ecliptic is variable, being faster in the wintertime than in the summertime. This is a con- 138 sequence of the fact that the earth's orbit about the sun is an oval-shaped curve called an ellipse. It follows from Newton's Law of Gravitation that the earth speeds up in its orbit when near the sun and travels more slowly when distant from the sun. "Now we can mention the two reasons why the actual sun and the time it provides with a sundial is not suitable as a time- keeper. (1) Because of the sun's variable motion in the ecliptic, the length of the day will vary and the time will not be uniform. (2) Even if the sun's motion were uniform along the eclip- tic, the length of the day and time by a sundial still would not be uniform because of the obliquity of the ecliptic. The obliquity of the ecliptic causes the sun to have a greater west-to-east motion at the summer and winter solstices than at the vernal and autumnal equi- noxes. "The astronomer remedies this situation by introducing a fictitious body called the 'mean sun' which travels at a uniform speed along the celestial equator, being the average rate of the actual sun. The time kept by this fictitious sun is called Local Mean Solar Time, whereas the time kept by the actual sun is called Local Apparent Solar Time. Local Apparent Solar Time, then, is what we read on a sundial. "The difference between Local Apparent Solar Time and Local Mean Solar Time is called The Equation of Time'. Astronomers can calculate the Equation of Time from their knowledge of the earth's orbit about the sun. The Equation of Time remains approximately the same from year to year and is tabulated in various almanacs such as the 'American Ephemeris and Nautical Almanac'. "Thus we see that we can apply the Equation of Time to a sundial reading to obtain Local Mean Solar Time. However, the time we keep on our watches in this part of the country is East- ern Standard Time which is the Local Mean Solar Time of the 75th meridian west of Greenwich. Chapel Hill being on the 79th meridian west of Greenwich has a local time of 16 minutes earlier than Eastern Standard Time. In order for the sundial to give Eastern Standard Time, it is necessary to apply the Equa- tion of Time giving the Local Mean Solar Time of Chapel Hill and then to add 16 minutes to give Eastern Standard Time. 139 The corrections found on the bronze plaque in the Southeast quadrant of the Morehead Planetarium Sundial is the Equation of Time plus 16 minutes and converts Chapel Hill Apparent Solar Time directly into Eastern Standard Time. — Morris S. Davis." Program of The Morehead Planetarium Sundial Presentation Ceremonies, June 3, 1956. THE NORTH CAROLINA STATE MUSEUM As one enters the North Carolina State Museum at Raleigh, he will see a section which was cut from a large cypress tree. This tree, cut in the Tuckahoe Swamp in Lenoir County in 1913, was estimated to be about 840 years of age. This attractive exhibit points out important historical events that took place at certain years as indicated by the growth of the tree. The infor- mation given is as follows : 1073 — Tree started to grow 1215 — King John and Magna Charta 1302 — First Mariners Compass in Europe 1492 — Columbus came to America 1584 — Roanoke Island Colony 1663 — King Granted Carolinas to Lord Proprietors 1792— Raleigh Made Capital of N. C. 1898— First U. S. Forestry School at Biltmore, N. C. This is a fitting: exhibit with which to greet the visitor. Here in the Museum one begins to increase his appreciation of the story of North Carolina, especially its natural history. This and the other exhibits which one will see as he makes a thoughtful tour of the entire Museum will cause him to look more closely at his rich heritage. These exhibits will not only give answers to many of the questions a visitor might have ; but more important, they will arouse his curiosity to the point that he will ask further questions. Students sometimes wonder what person arbitrarily drew a line on a map of North Carolina extending from Richmond County in the South to Northampton County in the North and called the land east of it the Coastal Plain. As one moves from one exhibit to another on the first floor of the Museum, he begins to understand this fact from the data he accumulates: • Fossil shark teeth were found in New Hanover, Columbus, Craven, Pitt, Halifax, Robeson and Wilson Counties. • Marine shellfish fossils, such as giant fossil oysters, honey- comb coral and fossil crinoid stems came from Onslow, Jones, Harnett, Edgecombe and Wake Counties. These data indicate that this Coastal Plain area was once covered by the sea. Simply reading about it does not impress this fact firmly on the minds of students ; a study of these ex- hibits, however, will help them remember it. 141 Every school year students ask questions about "shooting stars" or meteors: What are they? Do they hit the earth? Have any landed in North Carolina? Of what are they composed? A few minutes spent in a study of the exhibit on meteorites will partially answer these questions. For example, a metallic body weighing 160 pounds was plowed up from a heavy soil one- half mile east of the Uwharrie River in Randolph County. From 1922 until 1930 when it was identified as a meteorite, it was used as a barnyard anvil. It was then placed in the Museum. An analysis of a small piece of the meteorite showed it to be composed of a high percentage of iron and a lower percentage of nickel. An analysis of another metallic body on exhibit, which fell in Rockingham County in 1886, shows it to be composed of 87% iron and 12% nickel. Have you any students who raised questions about prehistoric life in North Carolina? They will be interested in knowing about the most famous fossil whale in this State which was known as the "Old Bone Foot-Log". This was because this complete backbone of a large whale served as a walkway across Fishing Creek, at a point between Halifax and Nash Counties, about two miles north of Whitakers. In time the "Footlog" gave way and the vertebrae were dispersed down the creek. Although this whalebone was lost as a possible exhibit, students will be fasci- nated when they study the exhibit of a Mastodon which was dug from a creek bed in Onslow County. As one observes this very large skeleton, he is taken back into the Ice Age, more than 15,000 years ago, when these prehistoric elephants roamed the coastal flats of North Carolina. What boy has not filled his pockets many times with rocks and wondered whether or not some of them contained gold, silver or precious stones? As his background in science increases, he wonders just what they are made of and where in North Caro- lina he can find samples of many types of rocks and minerals. A careful study of the hundreds of samples of North Carolina rocks and minerals in the Museum will furnish clues to the nature of such materials, and might cause one to become an amateur prospector in his spare time. Because of recent discoveries and advances in Nuclear Energy, reports are read almost daily in our newspapers about prospect- ing for radioactive minerals. These reports cause students to ask questions such as : Are radioactive minerals found in North 142 Carolina? What does pitchblende look like? Is it dangerous to be near samples of these minerals? There is a display in the Museum of radioactive minerals which are found in our State. One can see a beautiful sample of Uraconite (yellow uranium), which is a radium ore on granitic rock taken from the South Toe River in Yancey County. In addition, there are samples of Uraninite (pitchblende), Gummite, and Monazite Sand from Cleveland County. If a student is interested in doing a project on minerals of North Carolina, he will find many ideas and suggestions here on what to do. Such a project might vary from work with fluores- cent minerals, of which there is an interesting display, to build- ing stones, precious stones, metals and non-metals important to industry. As the student "digs out" this information, he will not only increase his knowledge of the geology and mineral resources of North Carolina ; he will also learn of interesting historical events. One such event, as given in the Museum, was the trip of Thomas Griffiths to the Kaolin City Pit in Macon County in 1776 to secure five tons of the Kaolin for Josiah Wedgewood, the famous English Potter. In one large room two stories high, there is a spectacular dis- play of fish. If one looks at this exhibit, closes his eyes and then opens them again, he will almost feel that he is in a large pool with all types of fresh and salt water fish around him. These preserved specimens range from Black Drum, Red Drum, Striped Bass, Pompano, Tarpon, Sturgeon, King Mackerel, Large Mouth Bass, Hammerhead Shark and Thresher Shark to other types, such as the Sting Ray and Seahorse. Many of these varieties will be new to students, who only have read about them or seen their pictures. For an appreciation of their beauty, size, and struc- ture, it is essential that a person see them. An hour of quiet study and meditation here will leave a person with the sensation of hearing the waves rolling on the beach and of feeling the salt spray on his face. For some reason, boys and girls show a keen interest in snakes, even though they might have developed a fear of such reptiles. Not only will the visitor to the Museum be able to examine many specimens of preserved snakes, but he will also be able to study live Canebrake, Timber and Diamondback Rattlesnakes, Copper- heads and Cottonmouths. As he observes these dangerous snakes, he will develop a healthy respect for them and learn to identify 143 them. He will see the head skeleton of a rattlesnake which shows the fangs, poison sacks or glands, and the course the poison must travel to reach the end of the hollow fangs. In addition, he will become acquainted with our non-poisonous snakes, will learn to recognize them, and will obtain information which will discount the many wild stories connected with hoop snakes, etc. A fascinating live exhibit to watch is the ten-frame observation hive of Italian Honeybees. A majority of students have never had the opportunity to look inside a hive and see the work of bees. What a thrill it would be for a person to be fortunate enough to see the Queen, which is possible but not very probable with this observation hive! When one visits the Museum for the first time, he might not realize that the exhibits have been arranged in a particular manner to tell the story of our natural history and to illustrate important concepts of science. Before one begins to study the exhibits of vertebrates, he should refresh his memory by examin- ing the well-prepared charts that introduce each section of the exhibits. These charts point out the division of vertebrates into warm-blooded and cold-blooded groups. In addition, they show that fishes are the most primitive and belong at the bottom of the scale. If one has forgotten, the charts will also cause one to recall that mammals and birds have a four-chambered heart, reptiles either a three or four-chambered heart, amphibians a three-chambered heart, and fishes a two-chambered heart. Un- less one gets this picture in mind, he might overlook some of the fascinating specimens, such as the one of the Glass Lizard. This is the so-called "glass snake" or "joint snake" about which so many false stories have been told. This reptile is really a leg- less lizard, not a snake. Having eyelids and ear openings, which snakes do not have, it is a true lizard without legs. To clear up misconceptions about this animal, the exhibit points out that this lizard's tail, consisting roughly of two-thirds of its total length, is easily broken when attacked. The pieces which are broken off continue to wiggle. The lizard usually escapes and grows a new but much shorter tail. An intriguing aspect of the insect collection is the number of unusual names. For example, one will see a "Devil's Riding Horse" under the order Orthoptera. Are your students familiar with Whirligig Beetles, Click Beetles, and Diving Water Beetles under the order Coleoptera? A careful examination will show 144 why one specimen is called Tiger Swallowtail and one Cloudless Sulfur under the order Lepidoptera. Will one familiar with the true bugs, think the names Electric Light Bug, Ambush Bug and Back Swimmer appropriate? If these names do not convince one that insects are interesting, then he might look at the life stages of the Royal Moth and see its caterpillar called the "Hickory Horned Devil". Space is too limited to give more than a brief sketch and to point out a few of the items in the total number of displays. One should not leave this educational tour, however, without a visit to the birdlife of North Carolina, because there one can add to the natural history atmosphere a delightful feeling of beauty. As one looks at the birds in their natural settings, he can almost hear the varied and whistled melodies of the Cardinal and the flute-like notes of the Woodthrush in the distance. There is one exhibit especially which should impress upon old and young alike the need for more understanding of our birdlife. Under the exhibit of two passenger pigeons are these words : "The last bird of this species died in the Cincinnati Zoo in 1914. Prior to 1872 there were millions of them. The last speci- men recorded in our State was near Raleigh in 1891. Again America was wasteful." Note: More than 30 information sheets have been prepared at the Museum to answer questions and provide additional infor- mation on many topics. Some of their titles are : Meteorites, Archaeology of North Carolina, Bats : Flying Mammals, Bird Banding, Waterfowl Refuges in North Carolina, Some Common Winter Birds of North Carolina, Snake Pests, The Black Widow Spider, and Native Poisonous Plants. Copies of these can be obtained by writing to: The Director, North Carolina State Museum. Raleigh, N. C. NUCLEAR ENERGY* Nuclear Facts of Reactor Life 1. "Atomic Energy" (properly it should be 'Nuclear Energy'), about which there is so much excitement in the world today, comes from a nuclear fuel. How ordinary heat energy is obtained from burning of wood, coal, and gas is well known. 'Nuclear Energy' is obtained by 'burning' nuclear fuel. The 'burning' * By Dr. Clifford Beck, formerly Head of Department of Physics, N C State College, Raleigh, N. C. 145 process is not the same, but in both cases a fuel is consumed, energy is released and waste residues are left. There are three usable nuclear fuels : (1) Uranium 235 (U235) which occurs in nature as 1 part in 140 of Uranium as it is obtained from its ores. Plants at Oak Ridge (Tenn.), Paducah (Ky.), and Pikeville (Ohio) are for separating U235 from the more abundant Uranium 238 (U238). (2) Plutonium 239 (Pu239) which is synthetically produced by nuclear trans- mutation of U238, (3) Uranium 233 (U233), which is syntheti- cally produced from thorium 232 (Th232). 2. Nuclear fuel, like gasoline, burns differently under different conditions. Under one set of conditions nuclear energy is re- leased at an explosive rate : the atomic bomb results. Under a different set of conditions, the energy is released at a controlled rate, as slowly or as rapidly as desired : This is called a nuclear reactor. Thus, a nuclear reactor is an accumulation of nuclear fuel which releases its energy at a controlled rate. 3. When nuclear fuel 'burns', either explosively in an atomic bomb or at a controlled rate in a nuclear reactor, three products are released : heat, nuclear radiations, and fission fragments (the 'ashes' of the nuclear fuel) . This is not dissimilar, in a superficial way, to the burning of coal, where the three products released are : heat, smoke, and ashes. 4. Heat from nuclear fuel : the major portion of the released energy. In an atomic bomb, most of the damage is caused by the tremendous quantity of heat released. In a nuclear reactor, most of the released nuclear energy appears as heat energy. More than 807c of the total energy is in the form of heat. All processes now in development for making usable power from nuclear fuel utilize the heat released when the fuel burns. For example, the temperature of water is raised, the water turns to steam, under pressure, which drives a submarine propellor shaft, or the turbine rotor of an electrical generator. Thus, nuclear fuel is used to supply heat instead of the usual fuels, oil and gas. In an atomic explosion, the major problem of the damage is caused by the sudden release of tremendous quantities of heat. A violent shock wave results, and the direct radiation can cause intense flash burns over large areas. 146 Heat from nuclear fuel differs from heat obtained from usual sources in only one major respect — the amount released from nuclear fuel is vastly more than a similar amount of ordinary fuel would yield. 'Burning' one pound of uranium releases as much heat as can be gotten from 3,000,000 pounds of coal. 5. Radiation : To curse or bless. "Burning" nuclear fuel releases radiation along with the heat. This radiation is penetrating, damaging, destructive. It is com- posed of high speed neutrons, gamma rays, X rays, beta parti- cles, and other entities : a complex array of projectiles and energetic radiation which can cause a variety of ionizing and collision interactions with the atoms of surrounding materials. Damage: living organisms exposed to large doses of nuclear radiation are damaged or killed. Inanimate materials may have their useful properties damaged or destroyed. Metals may lose their strength and change their shape. Plastics may be embrittled or decomposed. One of the chief problems in utilizing the heat from a nuclear reactor to make power is to find suitable materials of construc- tion which will withstand the damaging effects of radiation. The difficulty is intensified by the health hazards associated with intense radiation. In an atomic bomb, though most of the damage is caused by heat, there is more than enough powerful radiation to injure or kill many people who might escape otherwise. Blessing: Radiation may also be useful. It offers promise of being useful in sterilization of foods. It can be used to create radio isotopes for diagnosis and treat- ment of certain diseases. It has application as a research tool in every field of science. The greatest value of nuclear processes to mankind may well turn out to be the research knowledge gained through the use of radioactivity. 6. Fission Fragments: the "ashes" to bury. The fragments of "burned" uranium atoms constitute a most unusual type of "ashes", which must be periodically eliminated from the reactor. Each fragment is an atom of another element, an atom !/3 or Yi as massive as a uranium atom. Thus, these fragments are atoms of the "middle elements" of the periodic table. But they are not the stable, well-behaved atoms of iodine, molybdenum, tin, etc. ordinarily encountered. Each fragment 147 is a wildly excited, unstable, radioactive atom, shooting off rays in all directions. Fission products therefore are highly radioactive. They grad- ually lose their radioactivity, but much of it remains for hun- dreds of years. These products are poisonous to a reactor, and occasionally must be removed. But where does one then put them ? Bury them in sealed banks? Mix them with concrete and drop them in the ocean? These are not good solutions but hardly any better ones are known. One of the most difficult problems to be solved in any future nuclear power industry is to find a good means of disposal of the fission products. Are fission products useful ? Not very much as yet, though ideas of possible applications are beginning to appear. After an atomic explosion, the dangerous "fall-out" which rains down over a vast area down-wind is largely radioactive fission fragments from a "burned" nuclear fuel. These are the essential facts one needs to know about nuclear processes to have a superficial understanding of the way nuclear reactors work, and what they are used for. To gain real insight into these processes one needs to become acquainted with some of the fascinating things which go on inside of atoms and even inside the nuclei of atoms. Atoms, Molecules, Bonds of Union Who has seen the wind? Neither I nor you, But when the trees bow down their heads, The wind is passing through. It is the same with atoms and molecules. We have never seen these small units which make up all of matter, but from indirect observations and measurements and from properties of bulk accumulation of large numbers of atoms and molecules, we can come to know much about them. If a small block or a spoonful of any matter we know, either solid, liquid or gas, is divided into successively smaller and smaller parts, each piece will have exactly the same properties as the larger piece from which it was broken. A half or a hun- dredth or a millionth of a cup of water is still water. Eventually, however, if the division could be continued, such a small piece would be obtained that it could not be further divided without losing the properties of its bulk material. 148 This smallest possible particle of a material is either an atom or a molecule. An atom is the smallest possible sub-division of an element which still retains all the properties of that element. There are 90 some naturally occurring elements and 9 or 10 synthetic, man made elements. Hydrogen, carbon, iron, copper, mercury, plutonium, americium, and curium are synthetically produced elements. When an atom of one element is chemically bonded to an atom of another element, the combination is called a molecule of a compound. The major portion of tangible matter is made up of compounds. Water, sugar, sand, and metallic ores are common compounds. The properties of a compound are vastly different from the properties of the elements of which they are made. A molecule of water, a liquid having many interesting and well known prop- erties, is made up of an atom of hydrogen and 2 atoms of oxygen, two dissimilar gases. Similarly with sugar, which is quite differ- ent from the carbon and hydrogen atoms of which it is composed. What makes atoms hold together ? It takes a very strong force to break a piece of iron or copper. A one inch cube of iron con- tains more than 10 25 (10 billion billion million) atoms. W T hat holds these atoms together and makes iron so strong? What holds atoms of hydrogen and oxygen together to form water molecules? The water can be frozen into a solid, can be heated into a vapor. Still the molecules remain intact. What forces bind these basic units into integral components of bulk matter ? Before answering these questions, here are a few additional ones : What is an atom made of? It is seen that there are many differ- ent kinds of atoms ; that combinations of atoms form molecules ; and it is recalled that an atom is the smallest particle of an ele- ment which still retains the characteristics of that element. But can an atom be taken apart? And if so, what smaller components are found? The atom can be taken apart, and a description of what is inside is amazing almost beyond belief. Some of this will be described below. But to facilitate this description, a digression is necessary. 149 Forces, Electrical and Others A force between two objects may be either attraction or repul- sion. An attraction force tends to pull the objects together; a repulsion force, to push them apart. More than one force can be exerted at a given time. For example, a body may be lifted, even though the force of gravity tends to pull it downward. Forces may have many different origins. There are magnetic forces, electrical forces, gravitational forces, etc. Within the atom, several different types of forces may be identified, though why some of these exist is not knoivn. Electrical forces are the major ones within the atoms which can be identified and understood at least in part. Certain basic facts must be known about electric charges, to understand their importance in atomic structure. There are two types of electrical charges : positive and nega- tive. • Electrical charges do not exist alone; they are always "on" or associated with some particle or body. • All electrical charges, positive or negative, however large, are multiples of some basic, fundamental unit of charge, called e, which cannot be further divided. The unit negative charge is equal (and opposite) to the unit positive charge. • All "like" charges repel each other. (An electrostatic repulsion force exists between "like" charges.) • All "unlike" charges attract each other. (An electrostatic attraction force exists between "unlike" charges.) • The union of a given negative charge with an equal positive charge results in a net neutral, or zero, charge. • A charge in motion creates a magnetic field in its neighbor- hood. • If a charge moves across an existing magnetic field, a force is created which tends to push the charge off its direction of travel. (An electromagnetic force.) Gravitational forces are of some, though apparently not very large, importance inside the nucleus. It is not known why there is a force of gravity. It is one of the unsolved mysteries of the universe. But it is known that it exists, and how big it is. The Law of Gravity can be stated : There is a force of attraction between each body in the universe and every other body in the 150 universe. This force increases with the size of the bodies and gets smaller as the distance between the centers of the bodies increases. • For example, a stone on the surface of the earth is attract- ed by the moon and by the sun. It is also attracted by the earth. The stone does not "fall" away from the earth toward the moon and sun, because earth, being so close to the stone, exerts a much greater gravitational force. 8 In an atom, particularly in the nuclei of atoms, the par- ticles are almost infinitely tiny, yet they are so exceedingly close together (and relatively far from other bodies) that gravita- tional forces do have some importance. Centrifugal forces are of great importance in atomic struc- tures. Any body in motion can exert a force. Get in front of a baseball if you want this demonstrated. Furthermore, a moving body tends to go in a straight line, unless some force pulls (or pushes) it in another direction. A swiftly moving stone can be made to travel in a circle, if a string is attached and a steady pull is exerted on the stone. • The outward pull of a moving body, made to travel on a circular path, is called centrifugal force. The heavier the body, the faster it moves ; and the smaller the circle on which it travels, the greater is its centrifugal force, and the harder one would have to pull to keep it on its circular path. Unknown Nuclear Forces — If the electrical, centrifugal, gravi- tational, and all other known types of forces which should exist between the particles in atoms are added, not an atom (except possibly hydrogen) would stay together a single instant. The net preponderant forces would be repulsive, and the pieces would fly apart. Yet it is known that atoms stay together, and there are ways of measuring just how hard it is for them to be broken up. • Great mysterious, binding forces have been discovered in- side the nuclei of atoms, more powerful than any other forces known on earth, which securely hold the components together, even though there are, at the same time, known forces which would, alone, fragment the nucleus. Physicists are working very hard now to learn more about these mysterious binding forces, and perhaps soon they will understand more about them and what their origin is. 151 Components of Atoms: the Building Blocks of the Universe Now, what does one find inside an atom? The answer is amaz- ing: take a typical atom apart (with suitable detecting instru- ments) and four things are found inside : 1. An external ring, or cloud, or blurred cloud of exceedingly high speed electrons whirling in circular paths about the center of the atom. • Stop one of those electrons and "look" at its properties: It has a tiny mass (less than l/2000th part of the mass of the atom), a single unit negative electrical charge. What makes the electrons stay in curved paths about the atomic perimeter? (See below.) 2. An exceedingly tiny core at the center of the atom, called the nucleus, in which most of its total mass is concentrated. Besides mass, the nucleus carries one or more units of positive electrical charge. • Later it will be explained how this nucleus can be further opened to reveal "a world within a world". 3. A balanced system of electrical and centrifugal forces be- tween the whirling electrons and the unlike charges on nucleus and electrons. • There are always, in a normal stable atom the same number of electrons, and hence negative electrical charges, as there are positive charges on the nucleus. Thus the overall net charge of an atom is zero. 4. A great volume of empty space. The total mass of an atom is contained in the nucleus (more than 99%) and in the elec- trons (less than 1%). Between the circular electron tracks, or shells, and the thousands of times smaller nucleus, there is mostly empty space. • The atom is a planetary system, with the nucleus as the center, and the electrons as planets, and the force between the center and the whirling planets the electrical attraction of un- like charges. • In the solar system, the sun is the center, the earth is one of the planets, and the force holding the circling orbs is gravity. • What makes the electrons whirl around the nucleus ? Or the planets circle around the sun ... at just such speed as to balance their respective attractive forces? It is not known. But if for a moment either should stop their endless circling, the outward 152 pull of centrifugal force would vanish, and, as a tiny ball on the end of a stretched elastic band, it would speed straight to de- struction in a giant crash with the massive center of its system. Here then is an atom : a tiny nucleus, with positive charges ; a surrounding cloud of whirling, negatively charged, electrons. How does one atom differ from another? By the number of elec- trons in the external shells and the number of protons and neu- trons in the nucleus. Hydrogen atoms have one electron ; carbon, 6 ; lead, 80 ; uranium, 92. But why does one atom have more elec- trons than others? To answer this, a look must be taken inside the nucleus. • But first one more word about molecules. Atoms bonded together form molecules. The bonds are always formed by the outer electrons of the atomic shells. All these electrons are nega- tively charged, hence when one atom approaches another, there will be repulsion between their external electron groups. But the repulsive force is not always dominant. The electron shells may get unbalanced (some of the electrons go in elliptical rather than circular paths, and a net positive, attractive force, or bond, may be established. Sometimes an electron is shared by the nuclei of two atoms, as if the electron went first around one then around the other. Sometimes the electron structure of one atom "fits" one atomic structure better than it does another. Hydrogen atoms "fit" with many others, and many hydrogen compounds are known: water (H^O), organics (carbon-hydrogen bombs), acids (HC1, etc.) . • The electron structure of oxygen bonds readily with other electronic structures, particularly those of metals. Thus many metals occur in nature as metal oxides, rather than as pure metals. • All chemical compounds in the world, and the vast phe- nomena of chemistry and chemical reactions, are dependent on the bonds between the external shells of electrons around nuclei of atoms. The total and complete chemical properties and behav- ior of any atom depends entirely on the number and configura- tion of electrons in its external shells. • Some combinations of atoms are readily susceptible to union, whereas other groups will not combine or will do so only under special conditions. Again, atoms combined in one config- uration, will often, if given the opportunity, move into a more favorable, strongly bonded, configuration. For example, atoms 153 of carbon and hydrogen in a given arrangement, form molecules of gasoline. In the presence of oxygen, if ignited, the carbon- hydrogen bonds are broken, oxygen enters into the arrangements and there results molecules of CO, C0 2 , H 2 0, etc. These are all much more strongly bonded than were the carbon-hydrogen links in the gasoline. Inside the Nucleus 100 million average size atoms side to side would span a length of one centimeter. 1000 billion nuclei of atoms would be required to cover the same distance. Yet within each single nucleus there is orderliness and complexity which astounds the imagination and transcends understanding. The strongest forces known are there, and quantities of energy more vast than exist anywhere else in the universe. Inside the nucleus, four different items may be identified : 1. Protons — These are massive particles, each 2000 times as massive as an electron, and each carries a single positive charge. In any given nucleus, there are a definite fixed number of pro- tons, and hence a definite, fixed number of positive charges exists for that nucleus. The number of protons in naturally oc- curring atoms varies from 1 (in Hydrogen) to 92 (in Uranium). The number of protons in the nucleus determines the identity of the atom, and indirectly, its chemical properties, for, in any atom, there are always exactly as many electrons in the external shells as there are protons in the nucleus. A carbon atom has 6 protons in the nucleus and 6 electrons in its outer shell, a silicon atom has 14, an aluminum atom 13. Thus, if a proton could be added to an atom of aluminum, an atom of silicon would result. This can be done. Even more, extra protons have been added to uranium, atomic number 92, the heaviest element in nature, and 9 new, ''syn- thetic", elements which were never known before have been built. 2. Neutrons — These are particles slightly more massive than protons, but they bear no electric charge. In the lighter atoms, there are about the same number of neutrons and protons inside a given atom. As the atoms become heavier, the proportionate number of protons decreases. Thus, carbon, which has 6 protons normally has 6 neutrons also, though the number may vary from 4 to 9. In uranium, the 92 protons are accompanied (in nature) by 146, 143, or 142 neutrons. 154 When two atoms having the same number of protons, and hence the same element identification, have different numbers of neutrons, they are called isotopes of that element. Thus, in nature, three isotopes of uranium exist, U234, (92 protons — 142 neutrons), U235 (92 + 142), and U238 (92 + 146). (U238 is 139 times more plentiful than U235, and U234 appears only in trace amounts) . Some elements have many isotopes ; others may have only one or two. Nature has some definite rules but not all clearly under- stood as yet about combinations of neutrons and protons which are permitted. If others are formed, they eventually disinte- grate. An atom possessing a combination of protons and neu- trons which forms a permanent, "permitted" nucleus is called a stable isotope. An atom possessing a nucleus having an unstable proton-neutron combustion, i.e., one which is not permitted and hence eventually disintegrates, is called a radioactive isotope. 9 A radioactive isotope has an unstable nucleus, and it ejects particles or "rays" from its nucleus until a stable proton-neutron combination is achieved. • In many cases, radioactive disintegration may involve emis- sions which increase or decrease the electric charge on the nu- cleus. This changes the identity of the atom from one element to another. Thus, uranium atoms which are unstable decompose very slowly, by a series of radioactive emissions into lead, a stable atom, (nucleus) . • No atoms heavier than lead, which has 60 protons, are stable. Twelve heavier natural elements are known, such as thorium, radium, polonium, uranium, etc., and nine man-made transuranic elements are known, such as neptunium, plutonium, americium, curium, etc., but none of these are stable and all are disintegrating, some slowly, some rapidly. 3. Nuclear Forces — Protons repel each other violently, for they all have similar electric charges. There are gravitational forces of attraction. There are curious, vaguely understood attractive forces between protons and neutrons; and finally, there are tre- mendous, over-riding bonding forces, unlike any forces known anywhere else in nature, which securely hold the particles to- gether (if the nucleus is a stable one). In some nuclei, the neutrons and protons are bound more strongly together than in others. In all cases the individual par- ticles within the nucleus are in rapid, unceasing vibratory motion 155 within the narrow limits imposed by the restricting bonds. The particles are not free, but they are in constant motion. In cases where bonding forces are not as strong, and where many par- ticles are in turbulent motion, it sometimes happens that one particle may get entirely out of the nucleus, as happens to mole- cules of water during evaporation, when they break loose from the water surface despite surface tension forces tending to hold them back. Thus, there is the phenomena of radioactivity in the heavy elements, mentioned above. Picture the nucleus, then, as an accumulation of protons and neutrons, in turbulent, ceaseless motion, held together by mys- terious, overpowering forces of attraction, despite lesser internal incompatibilities and repulsive forces. With smaller numbers of particles in the nucleus, up to 80, the number of neutrons do not greatly exceed the number of protons, and, for given proportions, stable nuclei are formed. For nuclei having more than 80 par- ticles, the number of neutrons greatly exceed the number of pro- tons for the most stable arrangements, and even these have seri- ous internal conflicts which lead to radioactive emission. Forces, Mass, and Energy Suppose one has 10 small steel balls. Each one weighs 1 ounce. Now suppose these balls are tied together with stretched elastic bands. What does the assembly weigh? (Neglect the weight of the elastic) . An answer, of course, is 10 ounces. Now suppose the balls are tied together with stronger elastic bands twice as tightly stretched, and the same question is asked. The same answer, 10 ounces, is usually given. Both answers are wrong.* This is something which is not yet completely understood, though it can be shown to be true, as evi- denced by the atomic bomb. Free neutrons and protons have definite, measurable, masses. Put two (or more) of them together, near enough for the power- ful binding forces to hold them bonded as a nucleus, and their total mass is distinctly less than the sum of their masses when separate. Furthermore, the larger the binding force that holds the particles together, the larger is the discrepancy in the total mass of the assembly. * Weight is here incorrectly used instead of mass. "Weight" is the pull of gravity on a given mass. In a given situation, weight is proportional to mass. 156 This of course, doesn't seem to make sense. What happens to the extra mass which has disappeared? The answer was given in 1905, long before anyone even knew the question existed, by Albert Einstein who, even before his death in 1955, was recog- nized as one of the greatest scientists of all time. Einstein ventured the idea that mass can be converted into energy, in fact into a great deal of energy. His famous equation E = mc 2 states how much energy one could get if a given mass is converted into energy. Take 1 gram of mass, multiply by the square of the velocity of light, and the answer is the amount of energy which would re- sult : 1 x (3 x 10 10 ) 2 = 9 x 10 2 ° ergs of energy m x ( C ) = E 9 x 10 ergs of energy equals about 30 million kilowatt hours of electrical energy. Thus one gram of mass, which would be about as much as is contained in a medium-sized safety pin, if totally converted into energy, in the form of electricity, would produce about IV2 million dollars worth of electricity. Now to get back to neutrons and protons bound together into nuclei of atoms. Any proton or any neutron bound inside a nu- cleus has less mass than it would have if it were free. (It might even seem that the strong binding forces had squeezed some of the mass away). What happens to this mass? Answer: It is re- leased as radiant energy. What is "radiant energy"? It is heat, or light, or x-rays, or gamma rays, or some other form of "elec- tromagnetic" vibration. It has no mass, it has no electric charge. it travels in straight lines, it always travels with the speed of light, it travels freely through a vacuum (as in interstellar space from the sun and stars) , it is absorbed in matter, though in some forms it can penetrate considerable thicknesses of mat- ter. Whatever its form, it eventually appears as heat in the matter which absorbs it. Fusion: The H-Bomb Suppose, for example, that two free neutrons and two free protons are somehow bound together in a nucleus (this would be the nucleus of a helium atom.) About 0.7% of the total mass of the four particles disappears as radiant energy when the four are bonded together. If one gram of helium should be created, a 157 huge amount of energy would be released. This is exactly what is done in the hydrogen bomb. The process is called fusion : It is the binding of lighter, less firmly bound nuclear particles, into larger, more strongly bond- ed nuclei. The starting materials, rather than free neutrons and protons, are atoms of hydrogen (whose nuclei contain one pro- ton) or atoms of deuterium (An isotope of hydrogen, called heavy hydrogen, which contains 1 proton and 1 neutron) or lithium (which contains 6 nuclear particles), but when these are forced into heavier nuclei, a huge amount of energy is released. Perhaps a word about how this Fusion of light nuclei into heav- ier ones is accomplished. The first thought likely would be to use pressure. Take hydrogen, for example, and exert such pressure on it that the atoms and their nuclei would be pushed close enough together for the powerful bonding forces to grab and hold them. However, this simply cannot be done; the repulsive forces between atoms are too great ; they cannot be pushed close enough together for the attractive forces to be effective. It can be done by violent collision of atoms against each other with such force that nuclei do come close enough together to stick, and these violent collisions can be caused by heat. Remember that atoms are always in endless motion. Therefore, if the tempera- ture of a tank of hydrogen gas is raised high enough, the atoms will become so agitated that their collisions will be with such force that their nuclei will fuse, with the release of much energy. Fusion is therefore called a thermo nuclear process, i.e., it is ini- tiated with thermal or heat energy (and of course it releases a great deal more heat) . When scientists first considered how light elements could be fused into heavier ones, and calculated how high the temperature would have to be to initiate the reaction, an answer of several million degrees could not be produced on earth. Even the surface of the sun is only 6000 degrees ! However, it was discovered that a temperature of several million degrees is obtained momentarily, during the explosion of an atomic bomb (explained below) . Here then was a way of igniting a "hydrogen bomb" : place the ingre- dients inside an atomic bomb, which then becomes the trigger for the more powerful H-bomb ! Perhaps, other, singular, ways of triggering have now been found, but the fundamental process of fusion is still the same. 158 Fission: The A-Bomb Now to return to the neutrons and protons and binding forces which make up the nuclei of atoms. (Notice that nothing is said in the discussions of Fusion above or Fission below about the external electron shells of the atoms. These electron shells are simply insignificant and trivial, when compared with the vast forces in the nucleus, even though they are of utmost importance in all chemical and physical processes of matter) . It has been said that some neutron and proton combinations are more firmly bound than others. The heavy elements for ex- ample, have nuclear agglomerates which are not strongly bound, and in which there is internal incompatibility. Elements above lead (No. 82 which has about 207 nuclear particles) are all ra- dioactive, which indicates the lack of strong bonds, and there are no elements in nature above Uranium (No. 92, having 238 nuclear particles) , which indicates the instability and loose bond- ing of larger agglomerates. Likewise, as indicated above, the bonding in the very light elements is not very strong. The ele- ments near the middle of the periodic table are thus the most strongly bound. Chronium (No. 24), Cobalt (No. 27), Copper (No. 29), Krypton (No. 36), Zirconium (No. 40), Silver (No. 47), Xenon (No. 55), etc., are the most strongly bound of all the elements. Take Palladium (No. 46), for example. It contains 46 protons, just half of Uranium (No. 92), and 60 (±4) neu- trons, a total of 106 nuclear particles (±4). These particles are bound much more strongly than are the 236 odd particles in a uranium nucleus. Now suppose a uranium nucleus should some- how be divided into two parts. Each part might contain 46 pro- tons and 72 neutrons, which would resemble a palladium atom, with too many neutrons. If a few T free neutrons are released dur- ing the splitting, two atoms of palladium would result, and the individual particles in the two fragments would be a great deal more firmly bound than they were in the original uranium nu- cleus. Thus, a net loss of mass would result, and a corresponding amount of coal. This is just what happens in the fission of uran- ium nuclei. Fission is the splitting of a uranium nucleus into approximate- ly equal fragments, accompanied by the release of a large amount of energy and several (between 2 and 3) free neutrons. The nu- clear fragments are nuclei of lower atomic weight elements, but 159 they contain an abnormally high number of neutrons and hence are highly radioactive. The cause of fission : remember that the nuclei of heavy atoms are already unstable, with "internal incompatibilities" which cause them to be radioactive. If uranium 235 atoms are bom- barded with a stream of neutrons (several means of doing this are known) an extra neutron will occasionally get inside one of the nuclei. When this happens, there is a great excitement and commotion inside the already unstable nucleus, and the whole bundle of 236 particles flies apart in two (or sometimes 3) frag- ments, in what is really a big explosion on a sub-microscopic scale. The entry of the extra neutron is the "final straw" or trig- ger, which releases the pent up forces which were already on the verge of "letting go". When the fission occurs, due to the entry of one neutron into a uranium nucleus, the extra free neutrons released may in turn cause fission in other adjacent uranium atoms. Thus, there is a mechanism of a chain reaction: a neutron causes fission, which releases more neutrons which cause more fissions, etc., etc. In a given mass of uranium, if one fission leads to more than an addi- tional one, say two, the chain-reaction is divergent, and the rate of energy released quickly rises. (The time between one fission and the next is exceedingly short. Hence, an explosion may re- sult.) On the other hand, if all the neutrons released in one fis- sion are not allowed to cause additional fissions, the rate of fis- sioning may decrease, or be held constant, or allowed to rise slowly. This control may be achieved by inserting materials which absorb a portion of the neutrons without undergoing fis- sion. Boron and cadmium are notably good neutron absorbers. In a mass of uranium, arranged in such a way that a chain- reaction of fissioning would occur, the rate at which this fission- ing occur may be controlled by inserting boron or cadmium rods to greater or lesser extent. If a sufficient amount of "poi- son" is inserted, the chain-reaction practically ceases altogether. Fuel Supplies: Breeding Almost any of the heavy elements will .fission if neutrons of appropriate energy are fired into their nuclei. In some nuclei, fission occurs much more easily than in others, and in some cases more free neutrons, needed to sustain the chain reaction, are released than in other cases. This is similar, for example, to the 160 usefulness of various types of wood as fuel. Some woods will burn only if very high temperatures are applied ; some types re- lease more heat than others. Therefore, some woods are much more suitable as fuel than others. Investigation reveals that there is only one naturally occur- ring nuclear species which is satisfactory as a fission fuel, Uran- ium 235, though many other nuclei can be made to fission. The 139 times more abundant U238, as it occure in nature, is not a good nuclear fuel, and neither is thorium 232, which is another naturally abundant heavy element. However, it has been found that both U238 and Th232 can be converted by neutron bombard- ment into good fission-fuel. The process of this conversion is called breeding. Breeding : Bombarding Uranium 238 or Thorium 232 atoms with neutrons of suitable energy, so they are converted into good fission-fuels, Plutonium 239 and Uranium 233. respectively. When a neutron enters the nucleus of an atom it does not always cause fission (even in Uranium 235). In nuclei of Uranium 238 and Thorium 232, an extra neutron causes great excitement, which leads in most cases, not to fission, but to complicated emis- sion of radioactivity. The net result is to transform the U238 and Th232 nuclei respectively into an entirely new element and isotope which do not occur in nature : Plutonium 239 and U233. It is found that both these new materials are excellent fission-fuels. The means of accomplishing the transmutation of U238 or Th232 into Pu239 or U233 on a practical basis is an interesting one. Suppose a mass of U235, let's say 1 pound, is surrounded by a layer of U238 or Th232, and a controlled chain-reaction is started in the U235. A great deal of heat and many free neu- trons are released. The heat may be used (say to make steam) and some of the neutrons are used to keep the chain-reaction go- ing. There are many extra neutrons, however, and suppose that these escape from the U235 into the surrounding blanket of U238 or Th232 where atoms are converted into Pu239 or U233. When the pound of U235 has all been fissioned, the Pu239 or U233 can be chemically extracted from the blanket and used as fuel in place of U235. It has been found that for each pound of U235 (or Pu239 or U233) it is possible that more than one pound of new fuel can be synthesized : This can continue, of course, only as long as 161 there is a supply of U238 and U233. The U235 is needed to get the cycle started. On this basis, there seems to be ample supplies of fission-fuels to meet the power needs of the world for hun- dreds of years. Fusion and Fission Somehow it doesn't seem to make sense for energy to be re- leased, in one case, when heavy atoms (or more properly, the nuclei of atoms) are split and, in another case, for even more energy to be released when small nuclei are fused into heavy ones. The key to this paradoxical riddle, as explained above, rests in the fact that, in both cases, mass is converted into energy as nuclear particles move from one configuration to another in which the bonding forces are higher. In fusion, the problem is to push separated, small nuclei, close enough together against lone-range forces of repulsion, for powerful short-range attrac- tive forces to grab and hold the components. This is accom- plished by use of exceedingly high temperatures, far exceeding any ever known on earth before, and the heat released by the fusion raises the temperature even higher. Thus, an exceedingly transitory situation exists which leads to explosive release of energy on a large scale. It is difficult to see, however, how a steady condition involving such high temperatures could be maintained, or what materials could be used for containing such a reaction even if it could be controlled. Thus, at present, there are great problems to be overcome before a way can be visual- ized for controlling and containing thermonuclear, fusion, re- actions for production of useful power. The situation is vastly different with fission reactions. Here the process is initiated with a neutron, and each fission releases more neutrons. Conditions can be arranged that each fission re- sults in many more, which causes an uncontrolled, explosive release of energy. On the other hand, the use of neutron absorb- ers (poisons, such as boron or cadmium), which allow only part of the neutrons released from fission to cause successive fissions, provides a means of controlling the fission process at any de- sired level. Thus, heat at usable levels can be released. 162 . -,: - . i. ■•:■■! Mf* RALEIGH REACTOR In 1948 a committee was appointed in the School of Engineer- ing of North Carolina State College to study the future of the Physics Department in a new era of engineering resulting from the research efforts of the World War II period. This committee recommended that a strong Department of Physics working in the applied field be maintained at State College and that the staff be supplemented to the extent that advanced graduate and re- search work could be begun in this important Held. The out- growth of this was the nuclear engineering program. At the time the nuclear engineering program was begun in the fall of 1949, it was realized that industry would become increasingly involved with nuclear power production and that the fields of agriculture, life sciences, as well as other divisions of engineering, would use the by-products of the atomic age in their research and development. It was believed by those in the : By Dr. Arthur Clayton Menius, Jr., Head of Department of Physics. N. C. State College, Raleigh, N. C. 163 program at North Carolina State College that industry would urgently need men trained in those areas associated with nuclear radiation and nuclear reactors. At that time, however, there was very little evidence that such was the case in that the role of the engineer was being depreciated by those men in responsible positions and industry was showing very little inclination to become involved in nuclear power production. Those in the De- partment of Physics at State College, however, found a very sympathetic response in the students when this program of nuclear engineering was begun and with this encouragement immediate plans were made for the early construction of a small nuclear reactor on the College campus in the City of Raleigh. This was a novel idea at the time in that no reactor of any type had been constructed outside of the confines of national labora- tories operated by industry for the Federal Government. The complicating factor was one of security, especially in the use of highly enriched uranium which has a very significant mili- tary value. With the encouragement of the administration of the College, conferences were immediately begun with the Atomic Energy Commission in the hope that approval could be obtained for the construction, on an unclassified basis, of a small nuclear reactor to complement the training being given in nuclear engineering. The Atomic Energy Commission gave reasonable assurance to the College that the uranium fuel would be made available but at that time it was unable to provide funds for the construction of the reactor. The State of North Carolina, however, provided a relatively large grant for the initial studies and the design of the reactor which was later to be called the Raleigh Reactor. The staff of the Physics Department with the help of other staff members in the School of Engineering proceeded with the design of a 10 KW homogeneous nuclear reactor using the Los Alamos "water boiler," which was constructed during the war years, as the prototype. In early 1951 a concentrated effort was made by the reactor staff in the design of the reactor and at this time the adminis- tration of the University of North Carolina obtained a most gen- erous grant of $200,000 from the Burlington Mills Textile Foun- dation for the erection of a nuclear laboratory to house the reactor then being planned. This building is now known as the Burlington Nuclear Laboratories. During the period from 1951 164 to 1953 the construction of the reactor and the Burlington Nuclear Laboratories building was completed, and on September 5, 1953 the Raleigh Reactor was first placed in operation. This became the world's first non-Federally-owned nuclear reactor and represented fifty-one months — four years and twelve weeks — from negotiations, design, and construction to initial operation. The reactor operated satisfactorily for a period of twenty-one months and served an important role in the successful training of a large number of nuclear engineering students which in- creased from four in 1950 to three hundred seventy-five in 1957. In the spring of 1955, however, erratic operation of the reactor was noted and the reactor was closed down until the cause of the difficulty in operation was determined. It was soon found that a small leak had occurred in the reactor core and that the fission products which had been detected in the reactor room were escaping from the core. The fuel in the reactor was immediately transferred to a safety container which had been incorporated in the design of the reactor and the uranyl sulfate solution was returned in this container to Oak Ridge, Tennessee. A period of several weeks was required to dismantle the reactor with its associated parts and ship them to Oak Ridge where it could be examined and the cause of the failure determined. Careful examination revealed that there were five small holes in the walls of the stainless steel core caused by corrosion. This cor- rosion resulted from the presence of chlorine in the solution. Over the next few months a concentrated effort was made to redesign the reactor and to put it back into operation so that it could again serve the needs of the students in nuclear engineer- ing. Quite a few changes were made in the design of the reactor and it was again in operation on May 2, 1957. Thus, almost two years were required for the redesign and rebuilding of the reactor. The reactor has operated very satisfactorily since its reactivation and has contributed significantly to the nuclear engineering program. Physically the reactor consists of a solution container, the reactor core, which has a capacity of approximately four gallons. In this core is placed approximately two pounds of Uranium-235 in the form of a uranyl sulfate solution. This is surrounded by about twelve tons of pure graphite which reflects some of the neutrons that escape the reactor back into the reactor core. In order to protect the personnel from the radiation coming 165 from the reactor approximately 200 tons of concrete and thirteen tons of lead are used as a shield. Through this shield are ap- proximately fifteen exposure ports allowing specimens to be placed adjacent to the reactor core and also, in some cases, to allow neutrons to escape for certain experiments. In order to operate the reactor safely, electronic instrumentation is needed. This is one of the most important components of the reactor in that safety and quantative results depend upon it. In August 1957 a contract was let for the design and the con- struction of an additional reactor of a different type — a heter- ogeneous reactor. This differs from the present one in that solid uranium fuel elements will be used rather than using a fuel in a solution form. This reactor should be completed and in opera- tion by early 1959 and will, with the present reactor, provide a reactor laboratory which will be unequalled in this country for training and research possibilities. RALEIGH REACTOR NORTH CAROLINA STATE COLLEGE CHAPTER 6— PHYSICAL FACILITIES FOR TEACHING SCIENCE Science Facilities for Today's High Schools Planning For a New or Renovated Science Department • A Small High School • Renovations 167 Physical Facilities for Teaching Science PART A SCIENCE FACILITIES FOR TODAY'S HIGH SCHOOLS ' Communication is basic in the process of education. Knowledge about science is being accumulated rapidly. A technological society requires that all persons know some- thing about science. Education in science can be accelerated by using the media of communication more effectively. Physical facilities for high school science can be designed to improve the environment for learning. Students in mathematics can benefit from using science facili- ties. Subject matter in science, media of communication, needs of communities will change. Science facilities must allow for change. The facilities and environment for science teaching in high schools are means to provide effective communication for the teacher and the student. On the next page, PLAN A is a suggestion for a science layout in a large high school. This may be a separate building, or it may be part of a larger building. At the center is a "CORE" which contains accessible utilities : water, sewer, gas, electricity. The several rooms are separated from each other by partitions made of storage cabinets, work counter units, and shelving. These units of furnishings and equipment are spaced about a foot apart, back to back, to provide a "Chase" or shaft for util- ities to run from the "CORE" to the work counters and sink units. SECTIONS 1, 2, 3, and 4, are cross sections showing the "chases" between units of equipment. 1 Modified version of Science Facilities for Today's High Schools by Marvin R. A. Johnson and Henry A. Shannon, American School and University, 1957-58, American School Publishing Corporation, 470 Fourth Avenue, New York 16, N. Y., p. 223-230. 168 #?v : >r iCK GARDEN I I- I WEATHER STUDY 1 -tflJTJU : , 1 4 o°n X 4 I 1 I I I ' 1 I ! 1 I OUTDOOR CHEMISTRY LABORATORY SECT. 3 L PERSPECTIVE 1 on this page shows the classroom side of a unit of furniture located between a science room and a project- work room. This unit has storage cabinets in the lower section The upper section has chalk boards, which may slide and un- cover a picture screen for visual aids. This space might be used for a television screen when such an item becomes available for school use. In addition, the sliding chalkboards give access to shelving, which is also open on the project-work room side. This arrangement provides much storage space directly accessible to the teacher at the demonstration table. The sliding chalkboard can also provide an opening between the science room and the project-work room to permit easy supervision of both rooms. 170 PERSPECTIVE 2 on this page shows the project-work room side of the furniture unit between this room and the classroom. There are storage units in the lower section. The counter has a sink. Above the counter is a unit which has sliding tack boards. These give access to the shelving, which also serves the class room. The project-work room serves several functions: first, it provides storage space for equipment and supplies ; second, it is a small laboratory where experiments that might take several clays to complete may be set up ; third, this room can serve as a space for the rapid learner or the science-minded student to work under supervision during his non-class hours ; finally, the room is an area where teachers may carry on their experimenta- tion and research. 171 PERSPECTIVE 3 on this page shows a reading area, with shelving and display space for books, pamphlets, and magazines. This does not replace, but it supplements the school's central library. In the science reading area, students may be stimulated by publications readily at hand to do reading research. This space may also serve as a professional library area for the teachers. The science facility on page 169 has at its center a "CORE" which contains accessible utilities. If located on the ground floor, (where science rooms should be) the area of the core can be ex- cavated so that there is a space large enough for a workman to service the utilities. 172 PLAN B on this page shows the "CORE". From the "CORE" all serv- ice lines for water, sewer, gas, elec- tricity are run above the floor in the "chases" between cabinets, storage and counter units, and shelving. The science facility is a large open space between roof and floor, uninter- rupted by permanent walls, although there may be some well-spaced col- umns for structural support. i^SWS IN PLAN C, this page, partitions made from work counter units, stor- age units, shelving, and panels, have been installed to provide a two-room science facility, with auxiliary spaces for room, project-work room, and reading area. One science room can be used for biological sciences, the other for physical sciences and mathe- matics. The three other rooms may be used for classes other than science. If more science rooms are later needed, they can be provided by moving par- titions in these three other rooms. A plan similar to PLAN A on page 169. • )4 4.F *< Ff ,-»>>* *^* *>'•'-' «*•* * biology Mi si oeneral education laborotc IN PLAN D, this page, similar par- titions are arranged in another way to produce a different plan of rooms, using the same space and the core as shown in PLAN B. Now two rooms are shown with a corridor between them. Auxiliary science rooms are provided. The large room can be a general education laboratory, which will be available for classes in all sub- jects, for display, for meetings. The photographs on this page illu- strate some of the features suggested in the preceding pages. The storage wall is designed so that the science teacher can be more effici- ent. While he is teaching by use of demonstration, he can have all his materials near at hand. If he cannot have everything he needs on the dem- onstration table, he may store it on the shelving behind the sliding chalk- board until he is ready to use it. Visual aids should play an impor- tant part in science instruction. To avoid the inconvenience of a portable screen, a permanent screen is placed in one section of the storage wall be- hind the sliding chalk board. To re- duce interference from unwanted light on the screen, the screen is plac- ed in a recessed panel. Since television seems to offer many opportunities for supplementing the teacher's work, a large TV screen might someday be placed in this same space. In the first photograph, behind the storage wall is a conference room for the teachers. It will serve as a room for conferences with students and other teachers and as a curriculum laboratory. To fulfill his function effectively, the teacher must have con- ferences with all his students in order to direct them and their work. He must also spend much time in prep- aration for his teaching. Adequate physical facilities should be provided for these purposes. 174 The perimeter-type furniture ar- rangement shown offers many advan- tages. It provides "flexibility." It is no longer necessary to do laboratory work on specific days each week. If a situation has arisen within the class which calls for experimental work, the students can begin immediately since the facilities are in the same room. Many schools must use the science rooms as home-rooms. In the conven- tional science rooms with fixed lab- oratory furniture in the middle of the rooms, home-room students sit at un- comfortable and inconvenient tables. Also, they may disturb the experi- ments which might have been set up by science classes. With the peri- meter-type arrangement, these diffi- culties can be largely overcome. Sometimes teachers who have sev- eral sections of the physical sciences may also teach one or two classes of algebra. Most rooms in which mathe- matics is taught have few facilities other than chalkboards and tack- boards, besides desks. The physical science rooms can be used to distinct advantage for teaching algebra. Not only is there good table space, but also the environment encourages thinking on scientific problems. No one technique of teaching can be used successfully all the time. Even during one class period, several ap- proaches may be used if the design and furnishings will permit. In these photographs, students and teacher are developing a better understanding of science by approaching their prob- lems in different ways. The class 175 works as a whole for several days on a unit. Because of the differences in rate of learning, interests, and plan- ning of the teacher, the students then work in committees, carry on experi- mental work, consult with the teach- er, do reading research in the library, and take field trips. After several days of this type of work, they will be together again as a whole class. Note how readily the furniture in this general science-biology room can be rearranged to carry on these various learning activities. Outdoor Spaces Generally, in the drawings in this article, only those facilities within the buildings are shown. In PLAN A on page 169, auxil- iary spaces are shown out of doors, just outside the classroom. Glass walls may make these outdoor spaces become a real part of the planned science facilities. In any science class, some pupils might be in the out-door laboratory while others are working in- doors, all under the guidance and supervision of the teacher. The science facilities should extend even beyond these outdoor class room areas. The school site might include some other teach- ing aids such as the following : Arboretum School forest Tree growth demonstration Wild flower and rock garden Erosion control Fields for crops and horticulture Nature trails Wild life sanctuary 176 PART B— PLANNING FOR A NEW OR RENOVATED SCIENCE DEPARTMENT In North Carolina the size of the high school will vary from schools under 100 in enrollment to schools of 1500-2000 students. In addition there are approximately 50 schools classed as junior high schools. The majority of the schools have grades 9-12; a number are classified as senior high schools with grades 10-12. During the school year 1956-57, 469 of the 619 white and 167 of the 232 Negro high schools had less than 300 students enrolled. Thus one can readily see that small schools are predominant. To appreciate fully the need for science facilities in schools of all sizes, one must look at the science programs being offered. There are two factors which influence the work in all schools : (1) two units of science are required for graduation; (2) one unit in biology is required of all 10th grade students. The follow- ing data shows the nature and diversity of programs for a few schools of various sizes : A school with total enrollment of 159 students, grades 9-12. 9th grade physical science — 28 students, 1 section 10th grade biology — 41 students, 2 sections 11th and 12th grade physics — 25 students, 1 section A school with total enrollment of 235 students, grades 9-12. 9th grade physical science — 21 students, 1 section 10th grade biology — 65 students, 2 sections 11th and 12th grade chemistry — 18 students, 1 section 11th and 12th grade physics — 43 students, 2 sections A school icith total enrollment of 235 students, grades 9-12. 9th grade physical science — 79 students, 3 sections 10th grade biology — 66 students, 2 sections 11th and 12th grade physics — 12 students, 1 section A school with total enrollment of 321 students, grades 9-12. 9th grade physical science — 106 students, 3 sections 10th grade biology — 86 students, 3 sections 11th and 12th grade chemistry — 20 students, 1 section 11th and 12th grade physics — 18 students, 1 section A school with total enrollment of U60 students, grades 9-12. 9th grade physical science — 85 students, 3 sections 10th grade biology — 139 students, 5 sections 177 11th and 12th grade chemistry — 26 students, 1 section 11th and 12th grade physics — 42 students, 2 sections A school ivith total enrollment of 64.3 students, grades 9-12. 9th grade physical science — 129 students, 4 sections 10th grade biology — 210 students, 7 sections 11th and 12th grade chemistry — 33 students, 1 section 11th and 12th grade physics — 40 students, 2 sections 12th grade general science — 66 students, 2 sections A school of total enrollment of 851 students, grades 10-12. 10th grade biology — 315 students, 10 sections 11th and 12th grade chemistry — 120 students, 4 sections 11th and 12th grade physics — 27 students, 1 section A school with total enrollment of 1185 students, grades 10-12. 10th grade biology — 515 students, 17 sections 11th and 12th grade chemistry — 99 students, 4 sections 11th and 12th grade physics — 66 students, 3 sections A school ivith total enrollment of 1516 students, grades 10-12. 10th grade biology — 610 students, 20 sections 11th and 12th grade chemistry — 225 students, 10 sections 11th and 12th grade physics — 55 students, 2 sections 11th and 12th grade physiology and anatomy — 97 students, 4 sections 12th grade physical science — 42 students, 2 sections 12th grade advanced biology — 19 students, 1 section A study of these data will reveal several things which are important to the planning of facilities. 1. In some of the schools, 9th grade science is a required course, whereas in others it is elective. Whether or not it is required is a decision which must be made by the local school. This decision will have a pronounced effect on the space required for the science department. 2. Biology is a required course for all students. Because this is true, a logical place to start in arriving at the amount of space needed for science is to determine the number of sections of biology. For schools with grades 9-12, a "rule- of -thumb" guide is one section of biology for each 100 stu- dents in total enrollment. For schools with only grades 178 10-12, this will average approximately 1.4 sections for each 100 students in total enrollment. 3. It is difficult to predict how many classes of chemistry and/or physics there will be when a school passes an en- rollment of 250-300 students. There are two factors which should cause the enrollments in these two courses to in- crease : a. The increased emphasis being placed on mathematics and the physical sciences. b. The increase in enrollments in 9th grade physical sci- ence. 4. Generally one all-science room with accessory rooms will be adequate for a school with an enrollment of approxi- mately 250 students. 5. For a school with a total enrollment of 250-500 students, there should be one room for biological science, one for physical sciences, and the necessary accessory rooms. 6. For a school with a total enrollment of 500-750 students, there should be one room for 9th grade physical science and biology, one for biology, one for chemistry and physics, and the necessary accessory rooms. 7. When schools become larger than 750 students or when they have only grades 10-12, a more detailed study of cur- riculum and registration for the various courses must be made to determine the need for space. How should a department be designed and furnished to pro- vide a real learning laboratory or a special environment which will increase learning effectiveness on the part of science stu- dents and teachers? A first question to be asked is: What are the common types of learning activities that should be going on in the area provided? Dr. Hurd, in his book Science Facilities for the Modern High School, pages 9 and 10, has suggested the following : 1. Learning through reading Textbooks, workbooks, science biographies, current science literature, etc. 2. Learning through displaying Pictures, collections, mock-ups, bulletin boards, charts, specimens, aquaria, living plants and animals, posters, etc. 3. Learning through discussing 179 Class discussions, panels, small group discussions, formal and informal discussions, etc. 4. Learning through experimenting Individual experiments, student and teacher demonstra- tions, observations of phenomena, testing techniques, etc. 5. Learning through conferring Student committees, co-operative projects, interviewing, pooling of data, working together, etc. 6. Learning through visualizing Films, slides, film strips, photographs, museum visits, mod- els, telecasts, microprojections, displays, mock-ups, etc. 7. Learning through studying Organizing ideas, by writing papers and reports, self- testing, arranging and interpreting data, relating science to other courses, explaining science concepts to others, mak- ing applications of science to related problems, etc. 8. Learning through listening Tape recordings, records, teacher explanations, radio and TV programs, outside speakers, students' reports, etc. 9. Learning through creating Developing projects, devising new experiments or methods of experimenting, carrying on junior research, applying science principles to daily problems of living, etc. 10. Learning through guidance Providing guidance, making suggestions, planning a wide variety of learning activities, working with individuals, evaluating student achievement, providing source mate- rials, stimulating student activities, etc. 11. Learning through recreation Hobbies, collections, reading of science, radio and television science programs, etc. 12. Learning through related school activities Science clubs, science assembly programs, museums, na- ture trails, planetariums, observatories, nature camps, field trips, industrial trips, etc. From this list, it is evident that students must become engaged in many types of activities if they are to begin to understand science. In addition a situation is presented which shows that the teacher must use a variety of techniques. Can a department be designed which will accommodate these activities in an effi- 180 cient manner? The second question to ask, then, is: What guide- posts are there which will aid one in designing and furnishing this area? In the book School Facilities for Science Instruction, published by the National Science Teachers Association, pages 6-14, the following list of 20 general principles should serve somewhat as a guide in the preliminary planning of the department : 1. The selection of the site for a new building should be made, in part, with regard for the potential contribu- tions of the site and its surroundings to the teaching of science. . . . Careful studies of population and housing trends, early acquisition of large natural areas, and the planned preserva- tion of certain natural features for use by the school can make science instruction much richer than that possible in the classrooms alone. 2. School facilities for science should reveal that sci- ence IS A COMMUNITY AS WELL AS A SCHOOL ACTIVITY. ... It is important for growing citizens to realize that sci- ence is the concern of all persons and not of scientists alone. This can be done by the study of science in the home, the community services for fire protection, water systems, sew- age disposal, health clinics, park and recreation areas, gar- dens, farms, forests, and the like. 3. The planning of science facilities should utilize the ideas of many qualified persons. . . . Unless the architect and the board of education become sensitized to the ideas of the teachers and other qualified and interested persons, many valuable features are likely to be overlooked. Consideration of the ideas of lay citizens pro- motes support for the school, and seeking the ideas of teach- ers and other local citizens tends to avoid criticisms growing out of compromises which circumstances may require. 4. The amount of space in the science room should be adequate for a wide range of essential learning activities. . . . While the per student area can be expressed in square feet, even a seemingly generous allotment of space may in practice result in serious crowding and dangerous hazards. Then, too, a generous floor area may in practice be so static 181 that many desirable types of learning activities may have to be sacrificed, since adjustments in space cannot be made. The space for storage and experimental work so uniquely neces- sary in science indicates that science demands a very generous allotment of space per student. Note: In the high schools of North Carolina, a minimum of 30- 35 square feet per student is necessary in a multipurpose room. In addition the accessory rooms require 20-25% as much space as the multipurpose room. 5. The unique needs of science teaching should be antici- pated IN PLANNING such general features as floors, il- lumination, heating, ventilating, plumbing, and elec- trical SERVICES. . . . Science classrooms, laboratories, storerooms and other accommodations present certain unusual conditions. Acids and other chemicals may be spilled, various measurements must be made, temperatures must be kept constant in certain spaces and rooms, fumes and odors should be removed, some waste lines must withstand strong chemicals as well as resist amalgamation. 6. Rooms for science should be so designed and decorated that they are pleasant and attractive to the students, teachers, and others who use them. . . . Science rooms are all too often dingy, smelly and drab. Students and others may conclude that only persons with a peculiar interest would find satisfaction in working in such surroundings. Well-designed and decorated classrooms and modern science laboratories reveal ways to make science rooms pleasant and attractive while being highly service- able. 7. Rooms used for science should be so planned and equipped that their flexibility will provide for a vari- ety of uses, and for changes and adaptations to meet evolving needs. . . . Just as the science teacher may wish to rearrange fur- niture for class, small group, committee work or individual- ized instruction, so other teachers or group leaders using these rooms should find it possible to rearrange the room to meet the needs at the time. As the community changes, there may be a need for addition- al classroom and laboratory space for science. The convenient 182 placement of adjoining classrooms that can be easily converted for science teaching is highly desirable in the planning of school buildings. 8. Furniture adaptable to class, small group, and individ- ual WORK SHOULD BE PROVIDED FOR SCIENCE ROOMS. . . . While some special rooms and special furniture may be needed in the larger high schools, consideration of the vari- ous factors leads to the conclusion that science rooms should be so arranged and provided with furniture that they can be used for various science courses and for a wide variety of activities within each course. 9. School facilities for science teaching should make provisions for use of an abundance of real materials and forces. . . . The science teacher is peculiarly fortunate in being readily able to use the real things of the environment in his work. In some instances he does so outside the classroom, where the students study plants, animals, rocks, and the like, in their natural setting ; or he studies man's use of real things in the factory, the power plant, the dairy, or the transportation center. In many instances the actual things should be brought into the laboratory for examination, ex- perimentation and detailed study. 10. Schools should provide facilities where experiments and projects may be carried on for others to observe. . . . Many experiments require skill and care beyond that which most students possess. This means that there should be provisions in the science room for the performances of experiments as demonstrations for all the students to ob- serve. 11. Facilities for science instruction should include pro- visions FOR STUDENTS TO DO INDIVIDUAL EXPERIMENTAL WORK. . . . Actual work with materials and forces requires that sci- ence rooms be provided with a number of service connec- tions : gas, water, electricity, and sewer. Ventilation must be adequate, and there must be adequate and convenient work space for use by students. There must also be pro- vision equal to the need for apparatus, equipment, and sup- plies, together with facilities for collecting, growing and using living and non-living materials. 183 12. School facilities for science should include provision for constructing and repairing science apparatus and equipment. . . . The improvising of experimental and demonstration devices is typical of the work of scientists. In order to con- vey this spirit and to reap the instructional values of im- provising, there must be raw materials of wood, plastics, metals, glass and the like, together with the tools and facili- ties for making a variety of devices. 13. Science facilities should permit students and teachers to carry on experimental projects without daily mov- ing or dismantling of equipment. . . . The teacher and interested students may find it neces- sary to work for several weeks in arranging and using ex- periments. This means that special facilities for the prepara- tion and use of experiments are necessary in order that apparatus will not be disturbed while the experiments are in progress. 14. School facilities for science should include provisions for students to use published materials in planning their work, interpreting their observations, and study- ing the activities and findings of scientists. . . . The ongoing work of the science class provides many occasions for student reading. Planning for experiments, demonstrations, and projects requires familiarity with the literature. Interpretation of results requires reference read- ing. Through such occasions, the student should learn to utilize a broad range of reading materials, not the textbook alone. 15. School facilities for science should include space for proper storage of all materials related to science. . . . Some of the materials are relatively inert and storage without damage or deterioration is not a problem. Other materials are fragile, and some are corrodible so that fumes from chemicals used or stored may cause severe damage. The major problem is one of arranging for the proper stor- age of materials so that there will be little damage and at the same time keeping all materials readily available for use in teaching and learning. 184 16. Schools should provide facilities for using audio-visual and other sensory aids in science teaching. . . . Scientific research and the applications of science are so widespread that films, slides, recordings, radio presenta- tions, and television are needed to bring opportunity for seeing and hearing what is happening into the school. 17. School facilities for science should include provisions for displaying both improvised and manufactured prod- ucts and devices. . . . While the display of many items is desirable in science rooms, it should also be recognized that general display areas in the school corridors and the development of a school and community museum and science fairs are impor- tant means for making science an area of interest and value to students in the school and to adult citizens in the com- munity. 18. School facilities for science should include provisions for students and teachers to use mass media in bring- ing science to the school and community. . . . Much can be done if there are school facilities and en- couragement for science teachers and students to use as- sembly programs, public lectures, photography, radio pre- sentations, television stories and demonstrations, science fairs, store window displays, newspaper accounts, and the like, to interpret the science work of the school to the com- munity. 19. School facilities for science should include provisions for the science teachers to work on plans, records, orders, tests, and the like. . . . The science teacher must do all the planning and paper work that other teachers must do. In addition he must pre- pare for experimental demonstrations and individual ex- periments, and keep records of apparatus, equipment, sup- plies and other materials. Such records include current in- ventories and places of storage, lists of items to be ordered or recorded, catalogs, order forms, and the like. 20. School facilities for science should include provisions for the science teacher to confer with students as individuals or as small groups, and with parents, with the privacy necessary for satisfactory conferences. 185 . . . The science teacher needs to confer with students about project work to supplement and enrich the required class- work. Sometimes there must be conferences about conduct or marks. Parents sometimes want to discuss with the teacher their concerns about the accomplishments of their son or daughter. Each of these is a rather personal matter and must be discussed privately for a satisfactory confer- ence. A Small High School What will a department for a small school look like when many of these ideas are combined? If the carefully thought out pieces are put together with the one idea of providing an environment where science will become alive and meaningful for the boys and girls, it may look like the drawings on pages 189 and 190. There are other arrangements, some of which might be better. What changes should you make to suit your particular situation ? Even though the drawings are self-explanatory, it is well to look briefly at some of the areas. Since experimental work is a vital phase of any science course, this has received major con- sideration in the all-science room. At the rear of the room is a work unit 37 inches high with gas, water and electricity. This unit is set 6 inches from the wall in order to provide a pipe chase. This space is enclosed at the top by a splash board, in the front of which are placed the various services. It also provides a ledge for reagent bottles. To save the students' time and make them more efficient, storage is provided in the unit and on the wall above. The units for experimental work are dispersed in the room, one set being at the front of the room. In this area, there are two four-student work units and a demonstration desk, all pro- vided with all the services. This arrangement makes for more efficient use of che area at the front of the room, particularly if it is a wide room as is shown. The center of the room is furnished with two-student movable tables. These will be used for all the regular class work, plus certain types of experimental work. Since these tables are 30 inches high, they are also ideal for such types of work as the use of the microscope. The corridor wall is arranged for a number of activities. A focal point in this part of the room is the provision for several 186 types of displays. One display unit opens both to the corridor and to the room. Since it will be provided with all services, it will lend itself to rather elaborate as well as simple displays of projects. In addition there is space for displays on bulletin boards, peg boards and shelving. This is necessary, since all the sciences will be taught in this room. Every science room needs a library unit. The teacher and stu- dents will be collecting free and inexpensive publications. These are of little value unless an area is provided for the display and storage of these items. Combining this unit with the display units will not only provide a good working arrangement but will also add beauty to the room. Much has been said in the first part of this discussion on the value of the storage wall, sliding chalkboard, motion picture and TV screen, special project area, storage and dark room. Here it is well to point out briefly the special provision which is made in the storage-project room for experimental work on the part of the teacher and gifted science students. If used properly this space will enable a teacher to progress from a mediocre one to that of a master teacher. Here is a place where he can try out some of his ideas, engage in research work he desires and thus be a living example to his students of the interest and importance of scientific work. Renovations Most renovations are difficult. The reasons for this are ob- vious : an old building, water supplies far-removed, inadequate floor space, unusual arrangement of floor space, and the actual work of tearing out and replacement. All of these factors add to the increased cost to provide adequate facilities. In cases where a new addition is to be made to an existing school plant serious consideration should be given to including science facilities in the new structure. In many cases this cannot be done and thus there is no choice except to renovate. A first step to take in a renovation project is to survey the entire school plant to find the most suitable space. Quite often one will be surprised at the space he will find. For example, in one county new cafeterias were being built at several of the schools. When the old cafeteria space was examined, it was found to be an excellent choice for the science department. In another case, a new vocational building was constructed and the space 187 formerly occupied by the home economics department was found to be satisfactory for a science department. In still another case, an oversized room with a smaller adjacent room was renovated to make a very satisfactory department. In a few cases, it has been possible to tear out the partition between two rooms and thus obtain more adequate space. Finally, some schools have been able to provide additional facilities in the room now being used for science. In practically all of the renovations, the schools have found that they have been able to use many of the ideas that are incor- porated in modern departments. For example, extensive use has been made of perimeter type of furniture. The use of this type of furniture has solved many of the problems of plumbing. An- other unit which has been used successfully has been the com- bination demonstration desk and student work unit. This unit is approximately 12 feet long and has a top sink at each end. In addition to being used for demonstrations, it will also accommo- date three students at each end. A further attack on the problem is provided by the construc- tion of some of the furniture to be used. In many cases, the custom-made units will not fit the particular needs of the situa- tion. A good cabinet maker on the maintenance staff will usually be able to design and build a unit which will fit the space avail- able. Suggestions can be secured from the State Department of Public Instruction. The secret of successful renovations is ingenuity and careful planning. No set pattern can be formulated into which the reno- vation will fall. All will be different. This is a challenge to all of those concerned, but an answer can usually be found. The illus- trations on the following pages show some of the solutions that individual schools have found for their particular problems. 188 All-Science Room (See key on next page) 1 n 12 n l r- 1 1,0 1 r ■ ROOM 1 ■ 7 8 [] 6 4 n D5 D 3 1 □ □ i 2 ROOM 3 ROOM 2 n 2 3 |j| 4 3 D 190 Room No. 1 ALL-SCIENCE ROOM 1. Storage Unit, 7'-0" high 2. Storage Unit, 7'-0" high, with inset for motion pic- ture screen or TV re- ceiver 3. Sliding Chalkboard in three sections 4. Four-student Work Ta- ble, 37" high 5. Demonstration Desk, 37" high 6. Bulletin Board 7. Two-student Table, 30" high, movable 8. Display Unit in corridor 9. Library Unit, 48" high, with pegboard above 10. Display Unit for biologi- cal and physical sciences 11. Storage Unit, 7'-0" high 12. Work Counter, 37" high, with storage beneath and display above Room No. 2 STORAGE-PROJECT ROOM 1. Work Counter, 37" high, with storage beneath 2. Filing Unit for teacher 3. Storage Unit, locked, 7'-0" high 4. Storage Unit, open shelv- ing, 7'-0" high 5. Teacher's desk Room No. 3 DARK ROOM 1. Work Counter, 37" high, with sink 2. Work Counter, 37" high, with storage beneath 3. Storage Unit, locked, 7'-0" high 191 Plate Number One Renovation Room No. 1 PHYSICAL SCIENCE C R & LAB 1. Counter Work Space with storage, 37" high 2. Four-student Work Desk, 37" high 3. Bulletin Board 4. Demonstration Desk and Student Work Area, 37" high 5. Storage Wall Partition with sliding chalkboard Room No. 2 STORAGE-PROJECT ROOM 1. Work Counter, 37" high, with storage beneath 2. Storage Unit for chemi- cals, 7'-0" high Room No. 3 DARK ROOM 1. Darkroom Desk, 37" high 2. Work Table, 37" high 192 Plate Number Two Renovation Room No. 1 MULTI-PURPOSE SCIENCE ROOM 1. Chalkboard 2. Counter Work Space, 37" high with storage beneath 3. Demonstration Desk and Student Work Table, 37" high 4. Two-student Tables, mov- able, 30" high 5. Library Shelving, 48" high with bulletin board above Room No. 2 STORAGE-PROJECT ROOM 1. Storage shelving, 48" high 2. Physics Table, 30" high, movable 3. Storage Shelving, 7'-0" high, with one 5'-0" sec- tion locked. 4. Counter Work Space, 37" high, storage beneath Room No. 3 STORAGE ROOM 1. Storage Shelving, 7'-0" high 193 Plate Number Three Renovation Room No. 1 ALL-PURPOSE SCIENCE ROOM 1. Display Unit for Physi- cal Sciences 2. Library Unit with ad- justable shelves 3. Display Unit for biologi- science 4. Two-student Tables, 30" high, movable 5. Chalkboard 6. Pegboard 7. Work Counter, 37" high, with storage beneath 8. Demonstration Desk and Student Work area, 37" high 9. Storage Unit, 7'-0" high Room No. 2 DARK ROOM 1. Work Counter with sink, 37" high Room No. 3 TEACHER-CONFERENCE ROOM 1. Chalk Board 2. Table, 30" high 194 CHAPTER 7— SUPPLIES AND EQUIPMENT FOR SCIENCE • Uniqueness of Science Problem of Providing Supplies and Equipment • Basic Considerations for Determining Needs • A First Step in Preparing an Order Hints on Ordering • Source of Funds • State Contract • Time of Year to Place Orders • Supplies From Local Sources • Types of Reagents • Direction for Preparing Certain Solutions • Other Sources 195 Supplies and Equipment- for Science Uniqueness of Science Science may be considered as a unique subject in the high school curriculum — this uniqueness arising from the variety of materials which are necessary for effective teaching of the various courses. The usual materials, such as pencils, paper, chalkboards, bulletin board and textbooks, are needed as they are in other courses ; but in addition, special items are necessary if science teaching has meaningful experiences. In all science courses, observation and experiment are basic to good instruc- tion ; and these functions cannot be carried on unless proper supplies and equipment are available to students and teachers. In situations where little or no provision is made for these physi- cal facilities, usually where the appreciation of the meaning of science has not been developed, the students are exposed for the major portion of the school year to a "read-about talk- about" curriculum. Students in these unfortunate surroundings are being robbed of experiences which could have a pronounced effect on their lives. In addition, they are missing the thrills and excitement of discovering new things about their environ- ment through well-planned investigations. Problems of Providing Supplies and Equipment There should be little need to argue the case for experimental work and the need for supplies ; the impact of scientific develop- ments on present day living should convince everyone of the importance of adequate supplies for experimentation. Never- theless, many schools still do not have even the barest essentials for the work of science students. Why do these conditions exist in the mid-twentieth century? One of the important reasons is the lack of sufficient funds. Another factor is the lack of initia- tive on the part of those involved. A third factor is the lack of understanding of what is needed in a modern science depart- ment. It might appear to some that answers to these problems can be found easily, but this is not the case. Some of the equip- ment for science departments, e.g. microprojectors, vacuum pumps, and radio receivers, are expensive; smaller schools have difficulty finding the necessary funds with which to purchase such equipment. If the value of experimental work is not realized, 196 this lack of science equipment cannot be remedied overnight. Knowing what to purchase requires an extensive knowledge of the subject being taught; this cannot be achieved in a short period of time. Another factor which aggravates the entire prob- lem is the fact that in recent years there has been a rapid turn- over of science teachers. It is a most difficult job to develop a good science department in one year, or even during a two- or three-year period. If there is a change of teachers every year or two, the provision of supplies does not become a continuous operation ; and so the department fails to make substantial progress. In unusual cases, a department might use a piece of equipment only occasionally, thus resulting in a rapid deteriora- tion of that special equipment. Basic Considerations for Determining Needs Before a decision can be reached on what items to order for the science department, the program for the science courses must be planned. Decisions must be made as to what units of work are to be given, as to what the experimental work will be for each unit. In all science courses there are certain basic units of work which will be studied by all students. On the other hand there will be some phases of work which one teacher will stress, whereas another teacher will place emphasis on a different aspect of the topic. This is as it should be because teachers vary in their scientific backgrounds and special interests. Also, prob- lems proposed by different science classes will cover a wide range of topics. But this brings out the fact that items of equip- ment vary from school to school. Before an order for science supplies is developed, a careful inventory should be made. In the larger high schools, the num- ber of items will run into the hundreds. A teacher cannot keep in mind the condition of each item and how much or how many there are of each. The most satisfactory way to handle this matter is to keep a card file on each item. A card that is 4 in. x 6 in. in size is suitable to carry the name of the item, classifi- cation, the quantity, and the cost. It may be to the advantage of the science teacher to have the cards organized in broad areas, such as General Laboratory Supplies, Biological Mate- rials, Physics Apparatus and Chemicals, and within such divi- sions the cards may be arranged alphabetically. Such an inven- 197 tory should be kept up-to-date, new entries being provided as the stock is replenished. Before purchases are made, this inven- tory should be consulted. A First Step in Preparing an Order First it will be necessary to have recent catalogs from a num- ber of firms which sell scientific supplies and equipment. Having these catalogs available will enable a teacher to obtain a com- plete description of the item, its cost, and its catalog number. Otherwise, a science teacher will be "working in the dark", especially a beginning teacher who has had little experience with ordering. The teacher may save many hours of work by using prepared order forms. Four of these are given at the end of this section : (1) General Laboratory Supplies; (2) Biological Materials; (3) Physics Apparatus; (4) Chemicals. Many supply houses are organized on the basis of these classifications. For example, one supply house might handle only general laboratory supplies and chemicals ; another might handle only biological supplies and chemicals ; while still another might stock all the items in the four classifications. Setting up the forms in this manner makes it possible to place an item on a particular order form and it is not repeated on another one. There are advantages in having an item listed at only one place. If a school wishes to use these order forms, it is encouraged to do so. Better still, all of the science teachers in an administra- tive unit might take as a project the development of order- forms for the unit, using the suggested ones as a basis for their work if they so desire. Hints on Ordering Close examination of the order forms given here will reveal in- formation which should enable a teacher to prepare a better order. On the form for General Laboratory Supplies one will notice under "beakers" that the number of beakers per carton is given; there are 12 per carton for the 250 ml. size and 6 per carton for the 600 ml. size. If a school will order by carton of beakers instead of an odd number such as 31, this will facilitate the work of the supply house and will decrease the chance of break- age. On all the order forms, where it has been possible to pro- vide information of the above type, it has been done. 198 Source of Funds Before a teacher can complete an order, he must know how much money is available. At the present time, policies vary considerably in the State as to how much money can be spent by a school and as to how the funds are to be obtained. In one county, a dollar per student in each high school is placed in the budget prepared by the county board of education. In some units a specific sum of money, e.g. $150, is placed in the budget for each school. In a number of administrative units, no funds are allocated in the budget for science supplies ; in these cases each individual school has the responsibility for obtaining funds for its science department. In a majority of these schools, funds are secured by charging each student taking science a fee. These fees vary from $0.25 to $2.50. Unfortunately, there are some schools where no special effort is made to provide funds on a yearly basis from any source. Since conditions vary considerably from school to school, no specific plan for financing the science department is presented in this bulletin. However, it is important that each school or each administrative unit, place in the budget a specific amount for science supplies and equipment. Experience indicates that it will take at least $2.00 per year per student taking science to keep a department in good working condition once it has all the basic equipment. State Contract In North Carolina the Purchase and Contract Division in the Department of Administration receives bids each year for science supplies and equipment. Contract certification Number 334, listing companies awarded contracts, covers supplies and equipment not only for high school science departments but also for all State institutions. An inspection of this certification shows that high schools receive sizeable discounts on many items which they order, e.g., for 1957 two companies priced non-franchised items at current list price less 55'/' . Since many of the items ordered by high schools are non-franchised, such as ringstands, one can easily see that considerable savings are made by having State contracts. Contracts are renewed each year, becoming effective on Janu- ary 15. A copy of the contract certification is sent to each super- 199 intendent, thus making it possible for all schools to refer to it. If a high school wishes to have a copy of the certification, a request should be made to the Purchase and Contract Division, Department of Administration, Raleigh, N. C. Time of Year to Place Orders Orders for science supplies for a particular year should be completed by the latter part of the next preceding school year. This will enable the principal of the school or the superintendent of the school unit, to process all orders of this nature prior to June 15. Instructions as to the time the materials are to be shipped and to whom the invoice is to be sent should be clearly indicated on the order or by accompanying letter. If orders are mailed by June 15, sufficient time will be given for supply houses to fill the orders completely without any back-ordering and schools will receive the supplies at the beginning of the school year. This is important because it can become frustrating if supplies are needed in October and are not received until December. Supplies From Local Sources Occasionally during the school year the science teacher will find it necessary to purchase additional items; one large order placed once a year cannot satisfy all the needs. When a biology class plans to work with living material, such as protozoa and amoeba, an order will have to be made a few days before the materials are needed (some of these materials can often be col- lected in and around the school community). If items such as baking powder, corn syrup, saccharin, sodium bicarbonate and sugar are needed, they can be found at the grocery store. From the five-and-ten-cent store, one can obtain items such as cello- phane, copper wire, friction tape, glue, mirrors, rubber balloons, solder and tools. Chemicals, first-aid materials and photographic supplies can be purchased at drug stores. At auto-salvage shops one can get batteries, engines, generators, induction coils, mag- netos, safety glass, etc. Additional supplies can be purchased at camera shops, hardware stores, radio-repair shops, and tin and metal shops. All these sources, in addition to the scientific supply houses, should be considered when supplies are needed. 200 Types of Reagents The purest chemicals are the most expensive. If a chemical that is less pure will serve satisfactorily in an experiment, the school should purchase this grade and save money. The abbrevia- tions on the labels of the various chemicals indicate their quality. The abbreviations A.C.S. refers to the specifications of the American Chemical Society. These specifications are rigid and indicate chemicals of the highest quality. C.P. is the abbrevi- ation for chemically pure. However, it does not stipulate the maximum percentage of impurity and has not been denned for each reagent. The term "pure", used alone, usually specifies a low grade of reagent. The abbreviation "tech" refers to so-called "technical" quality. In general, such reagents are of a rather low grade of purity. The abbreviation N.F. refers to the National Formulary, which lists those formulas commonly used by physi- cians and druggists but gives no evaluation or approval. U.S.F. refers to the specifications of the United States Pharmocopoeia. Such reagents are of sufficient purity for druggists, but generally the standards are not as high as those of the A.C.S. Directions for Preparing Certain Solutions Many of the special solutions commonly used in the laboratory can be purchased from scientific supply houses. Instead of pur- chasing these solutions, it is suggested that they be prepared in the laboratory. This will provide a learning situation for students which should prove to be valuable. The following are a few that can be prepared: Ammonium Molybdate N : dissolve 88.3 grams of solid ammo- nium molybdate in 100 cc. of 6 N ammonium hydroxide. Add 240 grams of solid ammonium nitrate and dilute to one liter. Benedicts qualitative (for glucose) : dissolve 173 grams of sodium citrate and 100 grams of anhydrous sodium carbonate in about 600 cc. of w r ater. Dissolve 17.3 grams of crystalized copper sulfate in water and add this solution to the citrate-carbonate solution with constant stirring and sufficient water to make a liter of solution. Fehling's solution (sugar detection and estimation) : (a) cop- per sulfate solution : dissolve 35 grams of hydrated copper sulfate in water and dilute to 500 cc; (b) alkaline tartrate solution: dissolve 173 grams of rochelle salts and 125 grams of potassium hydroxide in water and dilute to 500 cc. Equal volumes of the two solutions are mixed just prior to use. 201 Methyl orange (indicator) : dissolve 1 gram of methyl orange in a liter of water. Methyl red (indicator) : dissolve 2 grams of methyl red in a liter of alcohol. Phenolphthalein solution (indicator) : dissolve 1 gram of phe- nolphthalein in 50 cc. of alcohol and add 50 cc. of water. Other Sources This section of the Bulletin should provide some of the answers to important questions. All of the information teachers need for proper ordering cannot be given. Other sources which the teacher should use are: college biologists, chemists and physi- cists, textbooks, laboratory manuals, magazines such as The Science Teacher, scientifically trained persons in the community, and other science teachers. ORDER FOR SUGGESTED GENERAL LABORATORY SUPPLIES From: Name of School Address of School Name of County To : Name of Company Address of Company State Contract No. 334 Charge to: Ship to: Quantity Catalog Unit Total Desired Number Description Price Price Apron, Laboratory, medium weight rubberized cloth; per per dozen $ $ Asbestos boards, squares, 4 inch Balance, analytical, for student use, capacity 200 g., sensitivity 1/10 mg. complete with two 10 mg. riders Balance, Harvard Trip, double beam, round stainless steel plates, cap. 210 g. sensitivity 1/10 gram. Balance, triple beam, stainless steel, capacity 610 grams, sen- sitivity 0.05 gram. Auxiliary weights, 500 g., for use with above Auxiliary weights, 1000 pis for use with above 202 Quantity Catalog Unit Total Desired Number Description Price Price Balance, triple beam, stainless steel, cap. Ill g., sensitivity 1/100 gram. _ $_ $ Balance weights, semi-analyti- cal, from 1 rag. to 100 g. Barometer, Mercurial, improved design Barometer, Taylor, Aneriod Beakers, Griffin Low form, with lip, "Pyrex", Capacity 250 ml., 12 per carton, order per carton or per case Beakers, Griffin low form, with lip, "Pyrex" Cap. 600 ml., 6 per ctn., order per carton or per case Beakers, Griffin low form, with lip, "Pyrex" cap. 1000 ml., 6 per ctn., order per carton or per case Beaker tongs Beaker Covers, watch glasses, diameter 75 mm. order per dozen or per gross Bottles, narrow mouth, with black plastic screw cap, capacity 8 ounces, order per dozen or per case. 72 per case Bottles, narrow mouth, with black plastic screw cap, capacity 16 ounces, 72 per case. Order by dozen or by case. Bottles, wide mouth, of flint glass, machine made. Capacity 8 ounces. 72 per case. Order by dozen or by case. Bottles, wide mouth, of flint glass, machine made. Capacity 16 ounces. 72 per case. Order by dozen or by case. Bottles, Dropping, Plastic screw cap, capacity 15 ml. Order by dozen or by gross. Bottles, Reagent, Relief letter- ed, narrow mouth, capacity 8 ounces. Acetic acid; Acetic acid, dilute; Ammonium hydroxide, dil; Ammonium hydroxide, con.; Hydrochloric acid, con; Hydro- chloric acid, dil.; Nitric Acid, con.; Nitric acid, dil.; Potassium hydroxide; Sodium hydroxide; sulphuric acid, con.; sulphuric- acid, dil. Order bv dozen assort- ed Bottles, washing, "Pyrex" brand, capacity 500 ml. Brush, test tube, puff-tuft, for % inch dia, tubes. Order by dozen or by gross Brush, burette 203 Quantity Catalog Unit Total Desired Number Description Price Price Burettes, white line, without stopcock, cap. 50 ml. $ _ $ Burettes, White line, with stop- cock, capacity 50 ml. Burner, Bunsen, for bottled gases Burner, Bunsen, with P.G.E. Top, for all bottled gases Burner, Tirril Type, all-brass. For all gases Burner, Fisher, High Tempera- ture, for all gases Burner, tip, wing tops, V2 inch diam. Burner tip, wing top, for P.G.E. top burners Burner, Alcohol lamps, cap. 120 ml., diameter of burner tube, 12 ml. Chart, Atomic, Hubbard, Wall size Chart, metric, Bureau of Stan- dards, wall size Clamps, Utility, Castaloy, with asbestos sleeves. For diameter up to Wz inches. Clamps, burettes, for diameter up to 1-1% inches Clamp, double burette holder. Clamp, Stoddard, test tube Clamps, Mohr Pinchcocks, flat jaws, for tubing up to % inches in diameter. S-V2" Clamps, Hoffman Screw Com- pressors, Open side, size of open- ing Vs x 1 inch . Combustion Boats, Coors, Por- celain, Glazed size No. 1 Combustion tubes, open ends, "Pyrex" brand ignition tube, length 300 mm . Condensers, Liebig, with rubber stopper connections, length of jacket 20 inches Condensers, Liebig, Separable, with plastic screw thread con- nectors, length of jacket 20 inches Corks, XXX Quality, regular length assorted. Bag of 100 Cork Borers, with individual Handles, brass, 6 in set Crucibles, Coors Porcelain, high form, size No. 204 Quantity Catalog Unit Total Desired Number Description Price Price Covers, Coors Porcelain, for size No. $ $ Cylinders, Hydrometer jars, with pourout height 12 inches x l- x / z inches O.D. Cylinders, double graduated, white line, capacity 25 ml Cylinders, double graduated, white line, capacity 100 ml. Cylinders, double graduated, white line, capacity 250 ml. Cylinders, double graduated, white line, capacity 1000 ml. Dishes, evaporating, regular form, Coors porcelain, size No. Files, Triangular, length 5 inches Filter paper, qualitative, smooth surface, dia. 11 cm. Filter pump Fire extinguishers, Carbon di- oxide type Size 2 First aid cabinet Flasks, boiling flat bottom, vial mouth, "Pyrex" brand cap. 500 Flasks, distilling, "Pyrex" brand cap. 500 ml. Flasks, Erlenmeyer, "Pyrex" brand, cap. 250 ml. Flasks, volumetric white line, with stoppers, cap. 1000 ml. Funnels, short stem, "58", di- ameter 65 mm Funnels, long stem, "58", di- ameter 65 mm. Funnels, separatory, globe- shape, cap. 125 ml. Funnel tube, thistle top, length of stem 300 mm Funnel tubes, thistle top, "Py- rex" brand dia. of stem 5V2 mm Kipp Generator, 500 ml. Glass Cutter Glass Tubing, soft 6 mm. Glass Stirring Rods, 150 mm. Glass Wool, Pyrex Jars, waste, glazed stoneware, 2 gallon Jar Cover, for waste jar, 2 gal- lon Labels, gummed, rectangular, size 261 Measure, meter stick 205 Quantity Catalog Unit Total Desired Number Description Price Price Mortar & pestle, Coors Porce- lain, size No. 0, 7 cm. S $ Dressing, Laboratory table top, acid-alkali resistant, black, #1 & #2 1 gal. of each is supplied Paint, Laboratory, per gallon : Pipette, measuring, white line, 10 ml. Plate, glass, square, 100 mm. Plate, Cobalt Glass, square 2 x 2" Wire, platinum, 24 gauge Retort, stoppered, Pyrex, 250 ml. Rubber stoppers, solid, assorted sizes 3-7 Rubber stoppers, 1-hole, assorted sizes 3-7 Rubber stoppers, 2-hole, assorted sizes 3-7 Rubber tubing, red, medium wall 3/16" I.D. Rubber tubing, red, medium wall 3/8" I.D. Plastic Tubing, Tygon 3/16" I.D. Plastic Tubing, Tygon %" I.D. Spatula, Coors Porcelain, Size 2 ____ Splints, Wood, bundle of 100 Spoon, deflagrating, iron Spoon, dispensing, plastic, per dozen Support, rectangular base, with rings, medium Support, test tube, 12-tube Test paper, Litmus, Blue, in vials Test paper, Litmus, Red, in vials Test paper, Lead Acetate, in vials Test paper, Turmeric, in vials pH Test Paper, Hydrion Dispen- ser pH Test Paper, Refills, Type A pH Test Paper, Refills, Type B Test tubes, chemical, with lip 6" x %" , Test tubes, chemical, Pyrex, w/ lip 6" x %" Test tubes, chemical, with lip 8" x 1" Test tubes, chemical, Pyrex, with lip 8" x 1" 206 Quantity Catalog Unit Total Desired Number Description Price Price . Thermometer, centigrade, -10 to 110 $ $ Thermometer, Fahrenheit, to 220 Thermometer, double scale, -10 to 110 C 10 to 220 F Tongs, crucible, brass Triangles, iron wire, pipe stem, 2" . Trough, pneumatic, galvanized iron, 10" Water bath, tinned copper, 5" diameter Wire gauze square, asbestos cen- ter, 5" x 5" ORDER FOR SUGGESTED BIOLOGICAL SUPPLIES From: Name of School Address of School Name of County To: Name of Company Address of Company State Contract No. 334 Charge to: Ship to: I. Living Material. Order for class of 25, 50, 75 or 100 students Amoeba proteus. Typical exam- ple of the Class Sarcodina. Pro- toplasm naked, several vacuoles. Paramaeium multimicronunclea- tum. A typical example of the Class Ciliata. Has one large macronucleus and several small- er micronuclei. Conjugating paramecia (Para- mecium bursaria. ) Has a distinct green color due to presence of alga. Culture contains opposite mating types. Euglena. Typical example of the Class Mastigophora. Has both plant and animal characteristics. 207 Quantity Catalog Unit Total Desired Number Description Price Price Stentor. Another example of the ciliate protozoa. Large enough to be seen by the naked eye. $ $ Volvox. Consists of many unicel- lular organisms joined together in colonial form. Brown Hydra. Excellent exam- ple of the Phylum Coelenterata. Brown Planaria. Excellent ex- ample of the Phylum. Platyhel- minthes. Good specimen to dem- onstrate re-generation. Vinegar Eel. Example of the P h y 1 u m Nemathelminthes. A Nematode. : — Spirogyra. Good example of the green algae. Has a spiraling ribbon-like chloroplast. Additional listing of organisms which can be used to supplement the above basic list. Vorticella. Stalk contracts when specimen is disturbed. Rotifers. Examples of common water organisms. Daphnia. Used for feeding hy- dra, small fish, and many other laboratory organisms. Tenebrio. Meal-worm larvae. Good insect to demonstrate metamorphosis of larvae to pu- pae to adults. Drosophila Cultures. These are the fruit flies used in the study of Genetics. Wild Type with "normal" characters as basic. II. Bacteria and Fungi Cultures. All are non-pathogenic. Order per culture. Physarum polycephalum. Grown in test tubes on agar. Excellent for study of streaming of pro- toplasm. Antibiosis. Set of two cultures supplied. A member of the Bacil- lus subtilis group and Sarcina subflava are used. Sarcina flava. Non-motile, gram positive spheres occuring in packets of sixteen to thirty-two cells. Aerobic. Produces yellow pigment. Chromobacterium violaceum. Motile, gramnegative rods. Aero- bic, facultative. Produces violet pigment. 208 Quantity Catalog Unit Total Desired Number Description Price Price Sarcina lutea. Non-motile, gram- positive spheres. Individuals ar- ranged in packets. Aerobic. Produces yellow pigment. $ $ Serratia marcescens. Short, mo- tiel, gram-negative rods. Aero- bic, facultative, produces red pigment. III. Aquaria and Terraria. Plants and Animals for medium size aquarium . Aquarium, 6 gal., with cover Aquarium, 10 gal., with cover Plants and animals for medium size bog terrarium. Terrarium, 10" wide x 18" long x 15y 2 " high _, Terrarium, 12" wide x 20" long x 18%" high Aquarium cement. Order per one pound can Aquarium nets. Four inches in diameter, strong wire handle, 14 inches long. IV. Culture Materials Sterile Agar Slants. For schools without autoclave or sterilizer. Order per dozen Sterile Tubes of Agar for pour- ing plates. Useful for individual student projects. Order per dozen. Sterile Agar Plates (agar in Py- rex Petri dishes). For those who have no means of sterilizing plates once they are poured. Or- der per dozen. Agar Plate Service. Schools mail Petri dishes and sterile agar plates will be prepared. Order per dozen. Wheat seed (preheated). Used in media for protozoa, turbel- laria, etc. Order per oz. Timothy Hay (preheated or not, as desired). Used separately or in conjugation with wheat in media for protozoa. Order per ounce. Fishmeal. Excellent fox cultiva- tion of Volvox, Spirogyra, and many other algae. Order per ounce. 209 Quantity Catalog Unit Total Desired Number Description Price Price Commercial Fertilizer. For cul- tivation of various algae. Order per ounce. $ $ Sheep Manure. Often used for Daphnia culture. Order per ounce. Drosophila Medium (Sterile). Ready to use in small culture jars. Order per jar. Culture Medium Materials Set. From these materials Media can be prepared in which a wide variety of protozoa, algae, water molds, and invertebrates can be cultured. Order per set. V. Instruments and apparatus for use in bacteriology as well as other routine culture work. Dissecting Scissors. Student quality, 4%" nickel plated. Or- der per dozen. Dissecting Forceps. Pointed tips, 4%". Order per dozen. Scalpel, Student Grade. All steel, 1%" blade. Order per dozen. Teasing Needles. Wooden handle, 6", straight points. Order per dozen. Dropping Pipette, Straight tip, 4%". Order per dozen. Dropping Pipette, Jumbo, 10". Order per dozen. Nichrome Wire Inoculating Loop. 8" metal handle with 3" nichrome wire, 25 gauge, 3 mm. loop. Order per dozen. Tripod Magnifier. Ground and polished lenses 25mm. diameter. Magnification approximately 10X. Cover glasses, Red Label, Non- corrosive, squares, 18mm.(%"). Order per ounce. Micro Slides, Red Label, 3x1 inches. Order per gross. Culture Slides. Thickness about 1.5mm., with one concavity about 15mm. wide and .75mm. deep. Size 3x1 inches. Order per dozen. Bacteriological Plugging Cotton, non-absorbent, unbleached. Or- der per lb. roll. 210 Quantity Catalog Unit Total Desired Number Description Price Price Dishes, Culture, Petri, Complete Units — Tops and Bottoms, Pyrex Brand Glass. $_ _ $_ Stender Dishes, Low Form. Com- plete with ground glass lids. Size 37 x 24 x /2 mm. Order per dozen. Culture Jars, Specimen Dishes or Finger Bowls, stacking type. An efficient jar for use in cul- turing amoeba and other pro- tozoa. Has many other uses. Size; 4%" x 2" and 8" x 3". Methyl Cellulose, 10%. Used for quieting protozoans. Order per ounce. Sterilizer, Arnold, Steam. Made of heavy copper, polished. In- side dimensions 12 Vz x 10%. Side door pattern. . Autoclave, Low Pressure, Cast Aluminum (pressure cooker, for steam sterilization. Capacity 16 quarts. . Microscope. 2 objectives, 10X and 43X. High Power Stereoscopic Binoc- ular Microscope. Leitz Prism Magnifer with a magnification of 10 diameters. This covers a 16mm. field of view, and has 79mm. working distance. . Microprojector. . Sub-Stage Lamp. Moulded of durable Bakelite. Has all-rubber cord and Bakelite plug. VI. Chemicals, Stains and Solutions . Acid Picric, saturated aqueous solution fixes all types of struc- tures, is also included in the formulae of some fixing solu- tions (Bouin's fluid) and in con- nective tissue strains. Order per lb. Alcohol, Acid, 1% hydrochloric acid in 70% alcohol for destag- ing sections. Order per 2 lbs. . Alcohol-creosote-xylol, a clear- ing solution especially useful in preparing whole mounts. Used immediately after absolute al- cohol. Order per 2 lbs. Borax-Carmine, a dependable and well known stain, widely used in preparation of whole mounts and for staining in bulk. Order per lb. 211 Quantity Catalog Unit Total Desired Number Description Price Price Bouin's Fluid, one of the best known general fixatives. It keeps well, fixes rapidly and causes very little shrinkage. Order per 2 lbs. $ $ Canada Balsam (Neutral in Xylol) one of the best known and most satisfactory mounting media. Order per 4 ounces. Creosote-X y 1 o 1, an excellent clearing fluid for whole mounts. Specimens do not become brittle and there is very little shrink- age. Order per 2 lbs. Eosin, aqueous solution, a good dependable cytoplasmic stain, generally used as a counter stain for hematoxylin. Order per lb. Fast Green, a beautiful, rapid stain generally used as a coun- terstain for carmine in prepara- tion of whole mounts. Borax. Order per 4 ounces. Glycerine Jelly, a mounting medium for nematodes and other small organisms. Order per 4 oz. Hematoxylin, Delafield's, one of the oldest and most satisfactory nuclear stains. May be used for sections or for staining in bulk. Order per 1 lb. Hematoxylin, Ehrlich's, a good preparation similar in action and appearance to Delafield's. It re- quires destaining, and according to some workers gives clearer differentiation than other hema- toxylins. Order per lb. Histowax (Paraffin). 5 lbs. 50-52° C( Melting point) 5 lbs. 56-58° C( Melting point) Iodine Solution (Lugol). Slides are passed through this solution in order to dissolve the mercuric chloride crystals which are de- posited by fixing solution con- taining this reagent. Order per lb. Lithium carbonate. An aqueous solution used to blue sections after destaining in acid alcohol. This treatment removes all traces of acid and assures per- manency of staining. Order per 2 lbs. 212 Quantity Catalog Unit Total Desired Number Description Price Price Mayer's albumen fixative, one of the most useful and widely known mixtures for attaching sections to slides. Order per 4 oz. $ $ Parlodion, used in place of col- lodion. A thin solution in ether- alcohol. In staining, the slides are passed into this solution from absolute alcohol, a thin membrane is formed which holds the sections on slide during sub- sequent treatment. Order per 4 oz. . . Wright's Stain, one of the best stains for floor film. All blood elements are well differentiated giving an excellent field for study. Order per 4 oz. Zenker's Fluid, Stock Solution. A popular fixative used especial- ly where very sharp differentia- tion is required. From 5 to 7% acetic acid should be added to stock solution immediately be- fore use. Order per 2 lbs. VII. Basic and Supplementary Lists of Prepared Slides . Basic Slide Set, 50 slides . Amphiuma Liver, sec. For study of the cell, its shape, nucleus, etc. The large size of the cells with the cell walls stained red, the nuclei blue and the pigment spots scattered throughout the section recommend this slide for study of cell size and shape. . Simple squamous epithelium (cell structure), from the top- most layer of the frog's epider- mis. The nuclei are stained blue and the cytoplasm red with the cell walls outlined in blue. . Amoeba proteus, w.m. These specimens are large, well-stained and show many pseudopodia and food vocuoles. Conjugating paramecia (Para- mecium caudatum), w.m. This is typical of the textbook pictures and also shows several of the conjugants in the period of nu- clear reconstruction. Paramecium in fission, w.m. On this slide the animals with at least five stages of fission repre- sented, are mounted in order. Two or three normal paramecia are also present. 213 Quantity Catalog Unit Total Desired Number Description Price Price . Spirogyra. Whole mount of fila- mentous green alga. Nuclei and spiral chloroplasts of vegetative cells, and stages in sexual repro- duction by scalariform conjuga- tion clearly shown. $ $ Volvox. Whole mount of green alga with spherical colonies showing daughter colonies in various stages of development. Bacteria Type slide. Mixed smears of three fundamental morphological types of bacteria- bacillus, coccus and spirillum. _ Rhizopus nigricans, bread mold. Whole mount showing rhizoids, sporangiophores, sporangia and zygotes. Coprinus, mushroom. Cross-sec- tion of pileus and gills, showing hymenium with basidia and basi- diospores. Puccinia graminis, wheat rust. Combination slide showing all stages of life cycle of wheat rust on respective host tissues: uredi- nia, uredospores, telia and telio- spores on sections of wheat stems; spermagonia and aecia on sections of barberry leaf. Ancylostoma caninum, w.m. male. The dog hookwork which is very much like the human hookwork is cleared to show the internal structure. Ancylostama canimum, w.m. fe- male. This hookworm is cleared to show the internal structure. Trichinella spiralis, teased, en- capsuled larvae in muscle. The worms are stained red in a green capsule. Grantia, c.s. for general struc- ture and canal svstem in which the choanocytes line the radial- canals and the gastro-vascular cavity. The stain is hematoxylin and eosin. Grantia, showing the four kinds of spicules which compose the skeleton of this animal. Hydra, w.m. with food, mainly small crustaceans, in the gas- trovascular cavity. Many of these animals show budding. 214 Quantity Catalog Unit Total Desired Number Description Price Price Pennaria, w.m. The medusa buds are between the rows of ten- tacles, and the hydranth is a short but large body arising from the stem. These slides are stained in carmine and fast green. $ $ : — Planaria, w.m. Two specimens are mounted on the same slide, one with the digestive tract com- pletely injected and the other stained for general structure. Moss, male head. Non-median longitudinal sections selected to show mature antherids with at- tached stalks and sperm cells. Moss, female head. Non-median longitudinal sections of mature archegone, selected to show ven- ter and portion of neck, with at- tached stalk. Fern prothallium. Whole mounts selected to show antheridia with sperms and archegonia on thal- loid gametophyte. Fern prothallium. Whole mount with young sporophyte attached to gametophyte, showing root and leaf. Fern sorus. Whole mount of leaflet with sorus containing sporangia and some sori remov- ed from leaf. Earthworm, c.s. posterior to the clitellum and showing general body structure. The gland cells in the hypodermia, the typhlo- sole, the dorsal blood vessel and the ventral nerve cord show in these slides. Small intestine, of Necturus, c.s. This slide is triple stained in Masson's stain and walls of the epithelial cells are clearly out- lined. Trachea of insect, w.m. The tra- chea with several branches show the tracheal rings, the nuclei stained in blue and the cyto- plasm of the cells stained in pink. House fly leg, w.m. showing the pulvillus stained blue with the rest of the leg in its natural color. The coxa and trochanter as well as the femur, tibia and tarsus are present. 215 Quantity Catalog Unit Total Desired Number Description Price Price Honey bee, w.m. This composite slide of the two wings, two views of the leg carrying the pollen basket and the sting with its poison sac is very instructive. $ $ Blood smear, frog. Numerous cells well spread are stained in hematoxylin and eosin and show platelets as well as the other white and red cells. Blood smear, human. The ery- throcytes and all of the various types of white cells and blood platelets are differentiated with Giemsa's stain. Typical dicot root. Cross-section of root to show central xylem with radiating arms, phloem, en- dodermis, starch grains in cells of cortical parenchyma, and epi- dermis. Typical monocot and dicot stems. Cross-sections of Zea (corn) and Helianthus (sunflower) stems enabling a ready comparison of structure in herbaceous mone- cotyledonous and dicoctyledonous stems. Tilia, basswood. Cross section of two or three year old stem show- ing all cells and tissues of a typi- cal young woody dicotyledon, and illustrating the concept of annual rings. Typical dicot leaf. Cross-section of mesophytic, deciduous leaf showing all cells and tissues, and illustrating such features of leaf structure as midrib, pali- sade and spongy mesophyll, and guard cells in lower epidermis. Leaf epidermis. Whole mount of epidermal cells peeled from leaf showing very distinctly the structure and spacing of guard cells and the nature of stomates. Ciliated epithelium, section from teachea of mamal. Shows the columnar cells with their nuclei and the cilia on the inner sur- face, and the goblet cells with their green contents. Masson's tetrachrome stain. . . Human bone, sections ground thin and mounted dry in balsam. Shows the Haversian canals. Haversian and interstitial lamel- lae, lacunae and canaliculi. 216 Quantity Catalog Unit Total Desired Number Description Price Price Allium Mitosis, onion. Longi- tudinal section of root tip select- ed to show all stages of mitosis. Stained with iron alum hema- toxylin bringing out the configu- rations of prophase, metaphase, anaphase and telophase very clearly. $ $ Lily flower bud. Cross-section of flower for floral diagram. Se- quence and arrangement of sepals, petals, anthers and pistil. Lily, cross-section of ovary with early embryo. Illustrates devel- opment of ovule (seed) within ovary after fertilization of egg, showing few-celled embryo, free- nuclear endosperm, nucleus, in- tegument, within locule of ovary. Corn grain. Non-median, longi- tudinal section of kernel showing tissues; embryo with epicotyl, primary root, cotyledon (acutel- lum), endosperm, aleurone layer and pericarp. Starfish eggs, w.m. Unfertilized eggs, early and late cleavage stages, gastrula and blastula, all differently stained are present on this slide. Frog development, sec. Repre- sentative sections of the unfer- tilized egg, early and late cleav- age stages, blastula, gastrula, yolk plug, early and late neural groove, early and late neural tube, hatcher and the 5-7 milli- meter stage are arranged in se- quence and stained in hematoxy- lin and eosin. The 33 hour whole mount and the 96 hour whole mount are offered as a set to show how much development takes place in a very short time. Ovary of adult cat, section. Shows several mature Graafian follicles with the contained ova and surrounding tissues and many immature ova in various stages of development. Hema- toxylin and eosin. . . Testis of cat, l.s. Shows general arrangement of seminiferous tu- bules and the details of develop- mental stages in spermatogen- esis and also the epididymis. Hematoxylin and eosin. 217 Quantity Catalog Unit Total Desired Number Description Price Price Sperm smear, guinea pig. Many individual sperm appear in one field, the tails are well preserved and the head and body are differ- entiated. Hematoxylin and eosin. $ $ Salivary glands, chromosomes. This slide is a smear prepara- tion of the salivary gland of a fruit fly larva and shows all the chromosomes with their light and dark bands. Supplementary Slide Set, 25 slides Mixture of plant and animal forms as they appear in pond and stagnant water. Volvox, Paramecium, euglena are a few forms seen. Vorticella, w.m. These speci- mens are expanded individuals showing the large U-shaped nu- cleus stained red, the cilia around the peristome and the pellicle stained green. Ancylostoma caninum ova, w.m. This is a companion slide to Z 990 and Z 991, the adult hook- worms. The ova are clearly visi- ble with segmentation in various stages. . Ancylostoma caninum infective larva, w.m. These larvae, raised in our own laboratory, are stain- ed with carmine and show the esophageoal bulb and the intes- tine and sheath. Cyclops or other copepods, w.m. These small orustaceans are of- ten found in drinking water out of wells or cisterns and pond water. They are stained carmine showing the jointed appendages so characteristic of this phylum. Daphnia or water flea, w.m. These crustaceans are also found in pond water. This slide has several specimens on it including some with parthenogentic eggs in the brood pouch, some with young daphnia and some of dif- ferent sizes. The stain in car- mine and green. 218 Quantity Catalog Unit Total Desired Number Description Price Price Clonorchis sinensis, w.m. liver fluke of man. This is an impor- tant human parasite in the Far East, from Korea to Japan through China to Indo-China and Inia. In this slide the inter- nal organs are clearly visible. The slides may be either singly or doubly stained. $_ Taenia pisiformia, dog tape- worm, w.m. Shows the scolex with its double row of hooks, typical segments of the imma- ture, mature and gravid pro- glottids mounted together on one slide. The stain is carmine with a counterstain of green. Mosquito life history, w.m. This is an interesting example of complete metamorphosis with the egg, larva just emerging from the egg, larva, pupa and adult. No stain. Grasshopper, w.m. mouthparts dissected. The labrum, two maxillae, tongue, two mandibles and the labium are mounted in their order. This slide demon- strates well the chewing type of mouthparts of insects. Plant Lice (Homoptera) w.m. Mature and immature aphids are mounted on each slide. The mouthparts are of the piercing- sucking type. Butterfly, w.m. proboscis. This type of mouthpart is known as siphoning and enables the but- terfly to reach the nectar deep within a bell-shaped flower. Housefly, w.m. head and mouth- parts. The proboscis is well dis- tended showing the end with its large flat surface and chitin- lined canals. This is the spong- ing type of mouthpart. Honey bee, w.m. head and mouth- parts. This animal demonstrates the chewing-lapping type of mouthpart. Combination of wing feather, down feather and filioplume, all on the same slide. 219 Quantity Catalog Unit Total Desired Number Description Price Price Smooth muscle cells from the stomach of amphiuma, teased. These cells appear singly and in groups, showing the characteris- tic spindle shape, non-straited cytoplasm and the centrally placed nuclei. The nucleus is stained blue and the cytoplasm red or pink. — Skeletal muscle (voluntary), teased. Shows whole and partial fibers with their striations, myo- fibrils, and the peripherally plac- ed nuclei. Stained with hema- toxylin and eosin. Heart (Human). Section show- ing typical structure of cardiac muscle. Students cannot miss seeing the branching fibers, cen- trally placed nuclei and cross striations in this preparation. Absolute presence of intercalat- ed discs will remove any doubt concerning their existence. Skin of cat, sec. Section through the entire thickness of the skin shows structure of typical layers and details of the hair follicles. Masson strain. Pine. Longitudinal section of male cone showing cone axis, microsporophylis and microspo- rangia (pollen sacs) with winged pollen. . Pine. Longitudinal section of young female cone at time of pollination, showing bract, ovuli- ferous scale, nucellus, integu- ment and micropyle. Pine. Longitudinal section of ovule showing archegone with egg nucleus imbedded in tissue of female gametophyte, sur- rounding nucellar tissue and in- teguments, and micropyle. : Lily, cross-section of anthers at time of dehiscence, with pollen sacs, connective tissue, anther slits, and mature, two-nucleate pollen grains. Germinating pollen. W h ol e mount of germinated pollen showing pollen grain, pollen tube and two male nuclei (sperm). 220 Quantity Catalog Unit Total Desired Number Description Price Price Composite mutations, multiple mutations, dorsal view. The fol- lowing five types are shown: eye- color, body color; three wing combinations, black-purple curv- ed, vestigial, and miniature. $ $ Supplementary Slide Set, 25 slides Anabaena. Whole mount of fila- mentous blue-green alga with heterocysts, stained to show chromatin granules. Penicillium, blue mold. Whole mount of mycelium with conidio- phores and conidia. Saccharomyces, yeast. Whole mount of cells showing budding. — Plasmodium vivax (benign ter- tian malaria parasite of man) blood smear showing various stages. This is the form com- mon in the southern part of the United States. Sporozoite from the salivary glands of anopheles mosquito. At this stage the parasites are small cylindrical forms ready to continue the infection in the next human bitten by the sick mosquito. Exflagellating gametes (Plas- modium vivax) stage in the life history of the human malaria parasite. This is the stage at which the mosquito is infected with malaria. Ookinete, w.m. the motile zy- gote, a worm-like organism which bores into the wall of the stomach of the mosquito and encysts. Oocyst, w.m. on wall of mosquito stomach under the outer limit- ing membrane. Here the sporo- zoites form and when the oocyst ruptures will be discharged into the body cavity of the mosquito. . Trichinella spiralis, section of skeletal muscle showing para- sitic infestation. The encysted larvae are shown occupying small spaces which are surround- ed by connective tissue. The lar- vae are sectioned in various planes. . 221 Quantity Catalog' Unit Total Desired Number Description Price Price Cbelia medusa, w. m. The re- productive organs are well-de- veloped and stained with car- mine while the tentacles and con- vex outer surface if the exum- brella are stained green. $ $ Moss, capsule. Longitudinal sec- tion of capsule with operculum and spore-bearing tissue. Fern rhizome. Cross-section of underground stem showing vas- cular tissues and stored starch grain food reserves. Rotifera, w.m. Several types of rotifers are shown. This is an excellent preparation for the study of external characteristics and comparison of the different types. Leech, w.m. small specimen flat- tened and mounted entire in bal- sam. External segmentation is plainly shown. Anterior and pos- terior suckers are evident as is the mouth with its chitinous teeth. Mussel, w.m. glochidia. Larval form of clam which may become parasitic for a short while on fish. Common redbug or North Amer- ican chigger, w.m. larvae. Sev- eral unstained specimens are present on the slide. Combination slide c.s. of cere- brum, cerebellum, medulla and spinal cord are mounted in order which enables the student to compare the characteristics of each division without the neces- sity of changing slides. Detailed structure of each section is well shown. Hematoxylin and eosin. Nerve cells. A smear prepara- tion from the spinal cord of ox showing the large motor cells with their nuclei, Nissl flakes and long dendrites and axones. Hematoxylin and eosin. Lung, dog, lobule is longitudinal section showing the arrangement of the bronchioles, terminal bronchioles and the respiratory epithelium of the alveoli. This slide gives an excellent picture of lung structure. 222 Quantity Catalog Unit Total Desired Number Description Price Price Tongue of rabbit, sectioned through the region of the foliate papilla. Several papillae are shown containing the oval shap- ed taste buds with their typical cell arrangement. Hematoxylin and eosin. $ $ Parotid gland, mammal, section. This preparation of a salivary gland shows the typical struc- ture of a purely serous secret- ing gland. The arrangement of the lobules with the branching of the excretory and secretory ducts is shown. Kidney and adrenal of rat, l.s. This slide shows sections of the kidney and adrenal gland in their natural relations to each other as well as the microscopic structure of each. Uterus, rat, l.s. This preparation shows a cross section of a preg- nant uterus with the embryo in situ. Structure of the fetal mem- branes and placenta, as well as the embryonic tissue of the un- born rat can be studied. This slide will enable the student to better understand the anatomical relationship existing between the uterus and the embryo. Cercariae of flukes, w.m. These are of some importance as they are the cause of "swimmer's itch." The external structure of body and tail is well seen with the nuclei being stained with carmine. Pediculus capitis, human head louse, w.m. adult. The adults are gray in color with the tarsus ending in a curved claw with which they hold onto hair. VIII. Plast-O-Mounts and Plastic Supplies Basic Set of Plast-O-Mounts, 12 in set Aurelia, jellyfish, w.m. to 1% inch specimen, stained to show mount, oral arms, radial canals, and gastric pouches with fila- ments and gonads. Starfish, w.m. larger specimen, mounted opaque to show exter- nal anatomy. 223 Quantity Catalog Unit Total Desired Number Description Price Price . Lumbricus terrestris, w.m. In- jected earthworm. The vascular system is injected with colored latex. Anterior third of speci- men dissected and mounted to show the "hearts" and connect- ing vessels in their natural posi- tion. $ $ Fresh-water Mussel, w.m. Small specimen with one half of shell removed to show the animal in place. The gills, foot, siphon, and adductor muscles are well dis- played. Garden Spider, w.m. Large speci- men mounted opaque to show the legs, mouthparts, and spin- nerets. Pieris rapae, Life History. Shows larva pupa, and adult to dem- onstrate complete metamorpho- sis in insects. Apis mellifera, Honey bee, w.m. of worker, drone, and queen mounted together for compari- son. A good example of a social insect. Frog Life History Set, w.m. In- cludes stages from the egg through the larval and tadpole stages and the adult frog. . Chick Embryo Combination Mount, w.m. 18, 24, 33, 48, 56 hour chicks mounted in series, cleared and stained to show the progress of development. Chick Embryo Combination Mount, v.m. 72 hour, 96 hour, 5- day and 6-day chicks mounted in series. Stained and cleared. Plastic is a safer mounting med- ium for these later ages than balsam mounts. Typical Teeth of dog mounted for comparison. Types include one each of incisor, canine, pre- molar with two roots, and molar with three roots. Seed Types. One of gymno- sperm-pine, and two of angio- sperm-corn and bean. The bean seed coat is dissected to show the dicotyledons. Supplementary set of Plast-O- Mounts set of 18 Grantia (Scypha), w.m. A sim- ple cycon sponge. 224 Quantity Catalog- Unit Total Desired Number Description Price Price Gonionemus, w. m. A large speci- men of a hydroid medusa. Clear- ed to show radial canals and gonads. $ $ Metridium, w. m. A small ex- panded specimen of the Sea ane- mone. Tapeworm Scolices Mounted for comparison. Includes Taenia, Dipylidium, Moniezia, and Pro- teocephalus. Armed and unarm- ed types of scoleces. . Strongylocentrotus drobachien- sis, green sea urchin, w.m. Shows the spines and the teeth on the ventral surface. Crayfish, w.m. Small specimen mounted entire to show the ar- rangement of the legs and other appendages. Uca, Fiddler crab, w.m. of a small male specimen. The male demonstrates the adaptation of an appendage for use in sex at- traction. Tick Combination including Boophilus, Dermacentor varia- bilis, and Dermacentor ander- soni. Useful to demonstrate the difference between the dog tick and the one which is the vector of Rocky Mountain Spotted Fever. . Romalea microptera, w.m. eggs and three stages of nymphs mounted to illustrate incomplete metamorphosis in insects. . Louse Combination including specimens of Haematopinus suis, Pediculus capitus, and Pediculus corporis. A sucking insect. Musca domestica Life History, larva, pupa and adult. Shows the stages in the life of a house fly which makes identification and control possible. Amphioxus, w.m. A large speci- men of this lower chordate clear- ed to show the gonads. . Hippocampus, w.m. of a mature male of a dwarf species. The specimen is bleached and cleared to show the embryos in the brood pouch. An example of a male animal which carries the young. 225 Quantity Catalog Unit Total Desired Number Description Price Price . Frog Eggs, w.m. of 14 stages of development from single cell to neural tube. Eggs are bleached and cleared to show the cleavage and internal structures of the later stages. $ $ Grass Frog Skeleton mounted entire and in prone position. May be viewed from all sides. Pea, w.m. Genetic demonstra- tion, smooth x wrinkled, 3:1 ratio through F 2 generation. An example of the Mendelian theory of inheritance. Venus Flytrap, entire plant showing both open and closed traps. An insectivorous plant. Leaf Types, w.m. shows an ex- ample of a simple leaf and a compound leaf together for com- parison. Beginners Plast-O-Mount Set Materials 1 lb. embedding plas- tic; 1 unit of catalyst; 1 unit accelerator; 1 measuring drop- per; 2 sheets sandpaper, no. 220, 440; 1 jar buffing compound; 1 glass mild; 1 instruction manual; several star flowers for practice embedding. Master Set Plast-O-Mount Ma- terials 1 lb. embedding plastic; 1 unit catalyst; 1 unit accelera- tor; 1 jar mold release; 4 oz. bottle cleaning fluid; 1 vial green transparent dye; 1 jar opaque red color; 1 measuring dropper; 1 glass mold; 2 sheets sandpa- per, no. 220 and 400; 1 jar buf- fing compound; 1 instruction manual; several star flowers for practice embedding. , Embedding Plastic. A synthetic polyester resin. Water-clear and requires only a heat of 100°- 140° to reach a maximum hard- ness. Order per lb., per 2 lbs., per 4 lbs. . . Catalyst. A tertiary-Butyl hy- droperoxide chemical which will cause the plastic to gel when it is incorporated with it. Order per unit, per 2 units; per 4 units, per 9 units. . . Accelerator. Used with the cat- alyst to speed the jelling time to two to five minutes at room temperature. Order per unit; per 2 units; per 4 units; per 9 units. 226 Quantity Catalog Unit Total Desired Number Description Price Price Abrasive Sheets. These sheets are used to finish the rough sur- face of a plastic mount. Order per dozen of No. 220; no 400! no. 600. $ _ $ Plastic Buffing Compound. Used to remove the fine scratches left on the mount after the abrasive sheets have been used. Order per 1 oz.; 4 oz.; 8 oz. Plastic Cleaning and Polishing Wax. Used to remove finger marks and to give a protective coating. Order per 1 oz.; 4 oz.; 8 oz. Electric Paraffin-Embedding and incubation Oven, Single Wall. Designed for temperatures up to 70° C. Heating units consume a maximum of 150 watts. Inside dimensions: 9%" high, WVz" wide and 10" deep. Specifv 110 or 220 volts; A.C. or D.C, IX. Preserved Materials for Dissection A s c a r i s Lumbricoides. The roundworm from pig or cattle. Large and well extended. Order per dozen. Asteiias sp. Large, 6-8 inches, Plain Starfish for laboratory dis- section. Order per dozen. Lumbricus terrestris (Chromic acid). Earthworms. Large se- lects, 9-12 inches with clitellum. Internally injected with chromic acid and preserved in alcohol. Sealed in metal tube. Order per 12, 24 or 36. Freshwater mussels. Extra large 6 inches and over. Pegged. Order per dozen. Cambarus, Plain. Crayfish. Body length 4-6 inches. Internally in- jected with preservative. Order per 12. Romalea microptera. Grasshop- per. Giant size. Body length 2-3 inches. Internally injected with alcohol and carefully preserved. In metal can. Order per dozen, or 25. Perca flavescens, Fresh water, Yellow Perch, Plain, Extra Large. Order per dozen. 227 Quantity Catalog Unit Total Desired Number Description Price Price Bullfrogs, Plain, Rana Catesbei- ana, length about 7 inches, over- all length about 14-16 inches. Plain preserved. $ $ . . Bullfrogs, Doubles. Rana cates- beiana. Same as above but art- eries and veins injected with colored latex. Grass Frogs, Plain, Rana pi- piens. Jumbo, 3% inches aver- age. Plain preserved. Order per dozen. X. Models and Charts Life size Torso and Head Model. Sexless complete with teacher's manual. Model of Eye. Shows the eyeball and the lower portion of the or- bital cavity enlarged about 5 times. The muscles, nerves and blood vessels of the eyeball and orbit are fully shown. The eye- ball is dissectible. Model of Ear. Enlarged about 4 diameters. Entire model is dis- sectible. Model of the Heart. Twice nat- ural size, mounted on stand. En- tire model is dissectible. Set of Zoology Charts. 30 in number. Size 24 x 36 inches. Set of Botanical Charts. 30 in number. Size 24 x 36 inches. Set of Physiology, Health, Hy- giene, Safety, and First-aid Charts. 30 in number. Size 24 x 36 inches. XI. Miscellaneous Supplies Slide Box. Bakelite, snap on cover. Capacity 25 slides 3x1 inch. Slide Box. Bakelite, hinged cover Capacity 100 slides 3x1 inch. Insect Mounting Boards. Made of soft basswood. The central groove is filled with balsa wood for easy pinning. Size: 19" x 3Vs" x V 8 " grooves. Pacific Sweeping Net. Strong muslin bag with canvas strip or rim. Complete with 15" hoop and 3' handles. 228 Quantity Catalog Unit Total Desired Number Description Price Price . Riker Specimen Mounts. The bottom is a cardboard box filled with absorbent cotton. There is glass neatly glued to both sides of lid. Size: 5 x 6 and 8 x 12. $ $ Insect Pins. Genuine Bohemian Pins of black steel with yellow heads. Sizes 00 to 7. Order per 100. Insect Killing Jars, Cyanide Bot- tles. Wide mouth, screw-cap. Jars are charged with cyanide. Size: 4 oz. and 8 oz. Lens Paper Booklets, 6x8 inches. 100 perforated sheets in durable binding. Plant Press. Student Grade. Size 16 x 12 inches. Weight 4 lbs., 12 oz. Dissecting Pins. Made of finest grade spring brass wire. Length 1% inches. Order per % lb. Dissecting Pan. Porcelain, with wax. Dimensions: 9" x 11 V2" x 2". Dissecting Set, Beginners. ORDER FOR SUGGESTED PHYSICS SUPPLIES From: Name of School Address of School Name of County To: Name of Company Address of Company State Contract No. 334 CHARGE TO: SHIP TO: Caliper, micrometer, English graduation, Range to 1 inch by 0.001 inch. Same as above but with Metric graduations, Range to 25 mm by 0.01 mm. Caliper, Vernier, Stainless Steel, Range to 12 cm; vernier to 0.1 mm. English graduation 0-5 in- ches in 16ths; Vernier to 1/128 inch. Slide rule, demonstration, 48 in- ches long by 8% inches wide, with A, B, C and D Mannheim scales. 229 Quantity Catalog Unit Total Desired Number Description Price Price Slide rule, Mannheim, with Lu- cite Magnifier, ten-inch scales on white enamel protected with clear lacquer. $ $ Slide rule Manual. . . Chart, metric system Capillary tubes, set of seven and support Brownian Movement apparatus, Dempster design (Note: need source of light and microscope to use apparatus) Osmosis apparatus, double this- tle tube and support. Complete with double-ended thistle tube, membrane, clamp and battery jar. Hooke's Law Apparatus. Inertia apparatus, ball and card form. Complete with ball and card. Collision apparatus with scale. Consists of 5 balls suspended by double cords from iron frame, tripod, 13 mm. nickle plated rod, 60 in. long, and graduated scale. . Composition of force board, all metal form, includes balances. Demonstration balance. Consists of support and lever clamp for demonstrating laws of levers. Lever knife-edge clamp. For clamping a meter stick for lever experiments. Wheel and axle, Bakelite Pulley, Bakelite, Single Pulley, Bakelite, Double Pulley, Bakelite, Triple Pulley, Bakelite, Triple tandem, plain bearings Pulley, Bakelite, double, tandem, plain bearings Pulley Cord, flax. 500 ft. Weight hanger, brass, with hook, will hold 1500 grams of weight. Pulley weights, to fit above han- gar. Set: 1 gram, 2 grams, 5 grams, 10 grams, 20 grams, 50 grams, 100 grams, 1000 grams. Jack screw model. Capable of raising 500 lbs. 230 Quantity Catalog Unit Total Desired Number Description Price Price Crane Boom, Ball Bearing, 70 cm. long. Complete with chains but without weight holders, weights or supporting rods and clamps. $ $ Crane Boom Derrick Set. Con- sists of 2 Crane Booms, pulleys, balances, fish line, clamps weight holders, weights. Inclined plane, all metal. Has vertical scale graduated in centi- meters and the arc in degrees. . Inclined plane with pulley. Con- sists of smooth-finished board. 120 cm. long and 12.5 cm. wide with pulley on one end. . . Hall's carriage. For use on in- clined plane. . . Scale pan. Made of heavy alumi- num 9.5 cm. in diameter. Used for carrying weight for inclined plane, etc. Stop watch. 1/5 second divisions. Registers up to 30 minutes. . . . . Metronome . . Simple pendulums, consists of 3 balls, cords, clamps, 125 cm. rod and heavy tripod. . . Acceleration apparatus, consists of a board, 150 cm. long, 13.5 cm. wide and 4 cm. thick with a cir- cular, shallow groove on one side. Complete with steel ball and lycopodium powder. . Double cone and inclined plane. Track is made of metal and dou- ble cone is of hard wood. . . Center of gravity apparatus, plumb bob not pi'ovided. . . Plumb bob. Metal cone 5 cm. long and 3 cm. in diameter with ring in top. Hand driven rotator, worm drive, 360° rotational plane, clamps to table top. Rotator accessories set. Consists of hoop, separator, globe, centri- fugal force apparatus, governor, siren and color disc. Demonstration Manometer stands 20" high and with tubes approximately 1 inch in dia- meter. Rigidly mounted with solid iron base. Cartesian Diver, complete with jar 231 Quantity Catalog Unit Total Desired Number Description Price Price Lift pump, plastic $ $ Force pump, plastic Pan with holder for use with pumps Boyles law apparatus. Consists of "J" form glass tube fastened to a vertical reading scale, with three-point base. Hydrometer, for both light and heavy liquids, 42 cm. long. . Hydrometer jar, with lip size 15 x 2 inches Specific gravity bottle. Size 25 cc. . . Specific gravity specimens, set of 10. Overflow can. Made of alumi- num, 13 cm. high and 7.5 cm. diameter. . Catch basket, with handle. Made of aluminum. Will hold 140 cc. of water. Aluminum cylinder, with hook. Size 7.5 cm. high and 2.5 cm. in diameter. Brass block with hook. 3.2 cm. each way Iron block with hook. 3.2 cm. each way. Lead sinker with hook. Weight 175 grams. . Eattery jar, round, white glass. Size 7 x 5 in. Size 8x6 inches. . Barometer, Hygrometer, Therm- ometer, Airguide Trio . . Maximum and minimum thermo- meter, Six's self registering. Hygrometer, Mason's. For deter- mining dew point and humidity. Complete with instructions. Hygrometer, or "sling" psychro- meter. Complete with instruc- tions. . Dew - point apparatus. Simple form. Complete with instructions but without thermometer. Rain gauge, United States Wea- ther Bureau Type. With instruc- tions. Planetarium, Trippensee, com- plete with booklet of instruc- tions. Wegner Vacuum and Pressure Pump, 110 volt, A.C. Motor with pump plate. 232 Quantity Catalog Unit Total Desired Number Description Price Price Air pump, compression and vac- uum, simple form $ $ Vacuum Rubber Tubing. Size, inside diameter of 7/16 inches and wall thickness of 5/16 in- ches per foot. Duo-seal oil for Rotary pumps. Per quart. Stopcock grease, high vacuum type. Per 2 oz. tube. Air Pump Demonstrator Acces- sories Kit (1) Bell jar, straight form, glass stoppered. Capacity 2 liters. (2) Freezing apparatus. Con- sists of a glass, wire tri- angle for support and Bell jar. (3) Magdeburg Pressure discs. (4) Bell in Vacuo. (5) Weight in air cylinder. (6) Guinea and Feather tube, triple purpose. Conductometer. Consists of six rods 5 mm. in diameter and 10 cm. long attached radially to a brass disc. Each rod has cavity at outer end for holding igni- tion solution. Ignition solution. Used with con- ductometer. Ignites with bright flash when dry. Convection of heat apparatus. Metal box, glass sides. Complete with lamp chimneys but without candle or touch paper. Touch paper. Does not burn with flame but produces smoke only. Per sheet. Hot water heater model. Made of glass. Radiometer, single rotator. Ball and ring, hand form. Per set. Thermostat, adjustable. Mount- ed on a wood base; 12 x 8 cm. Solderless boiler, hyposometer. Complete with stand. Linear expansion apparatus, Lever form. Complete with one steel rod but without thermo- meter. Aluminum rod, for Linear Ex- pansion Apparatus 233 Quantity Catalog Unit Total Desired Number Description Price Price Copper Rod, for Linear Expan- sion Apparatus $ $ Brass rod for Linear Expansion Apparatus Calorimeter. Complete with two aluminum vessels, bakelite cover, stirrer and fiber ring. Specific heat specimens, set of five. Per set. Manually operated automobile Engine Model Thermo-electric pair, Copper and German Silver. Bar magnet steel, rectangular. Size 15 x 1.9 x 0.7 cm. Magnet, alnico, horseshoe form. Size: 3 cm. high x 4.8 cm. wide x 1 cm. thick. Alnico rectangular magnets. Size: 30 x 19 x 14 mm. per pair. Support. For bar magnets to demonstrate attraction and re- pulsion. . Iron filings, in sifter top jar, per pound Electromagnet, U-form Dipping needle — can be used as a compass bv holding horizontal- ly. Compass, small form. For plot- ting magnetic fields. Compass, Bakelite case, Bar needle, can be carried in pocket like a watch. Electrostatics Kit (1) Solid glass friction rod. (2) Hard rubber friction rod. (3) Electrophorus, small (4) Electrical pendulum. Consists of insulating stand 30 cm. high supporting two pith balls. (5) Electroscope, flask form, with polysterene insulation. (6) Silk friction pad. (7) Flannel friction pad. Electrostatic Machine Kit Wimshurst static machine. Leyden Jar, one pint. Discharger, fixed type — Universal support, for holding electrostatic accessories. 234 Quantity Catalog Unit Total Desired Number Description Price Price . Bell chimes, five bells. Will fit above support $ $ . Electric whirl — will fit above support. Lightning Plate . Plate and Geissler tubes will fit above support. Electrostatic Demonstration Kit. Consists of 15 different items to use with static machine Photoelectric cell, dry plate type. Will deliver 1.4 microamperes per foot candle. Photoelectric cell holder for use with above Photoelectric demonstration kit complete with instructions. Students Cell. Complete with porcelain top, tumbler, copper and zinc elements. Zinc element. Flat. Size 22 x 125 mm. per dozen. Copper element, Flat, size 22 x 125 mm. per dozen. Lead element, Flat. Size 22 x 125 mm. Per dozen. Carbon element, Flat. Size 19 x 125 mm. Per dozen. Battery, Dry, little six . Daniels cell, gallon size. Com- plete but without chemicals. Storage battery, two place, open- type glass capacity of 8 ampere hours. . Power Unit. Gives either direct or alternating current at low vareable voltages from regular 110-120 volt, 60 cycle, A.C. line. Electromagnetic demonstration apparatus Electrolysis apparatus. A Conductivity tester, simplified form. . Primary and secondary coils, for induction effects. Complete with iron cone. . Induction coil, standard labora- tory form. Will give 6 mm. spark. Operates on 1 or more dry cells. Choke coil, simple form, com- plete with transformer, switch and lamp mounted on 15 x 40 cm. base but without induction coil such as No. 2399. 235 Quantity Catalog Unit Total Desired Number Description Price Price Magnetoelectric generator. $ $ St. Louis motor. With magnets and armature but without elec- tromagnet attachment. Electromagnet attachment, for St. Louis Motor. . Battery motor parts, little hust- ler. Complete with all parts needed to make motor. Short-wave radio demonstration apparatus. Barr design. . Telegraph set, student outfit. Demonstration radio receiver. A completely assembled 4 - tube radio receiver spread out on a large panel complete with in- structions. Demonstration Radio Transmit- ter. Demonstration Cathode Ray Os- cilloscope. Microphone. Telephone station, complete out- fit for one station. Galvanoscope, simple form. Complete with compass. Tangent galvanometer, simple form. Complete with compass. D'Arsonval Galvanometer, stu- dent form. Galvanometer six-in-one type. Can be used as a galvanometer, millivoltmeter, micrometer, volt- meter, Ohmeter and polarity in- dicator. Double scale voltmeter, D.C. Range 150 to 7.5 volts. Double scale Ammeters, D.C. Range 1 to 10 amperes. Double scale voltmeter, A.C. range 150 to 15 volts. Single scale ammeter, A. C. range 15 amperes Rheostat, air-flow, slide wire. Approximate resistance, 2.5 ohms. Current capacity 13 am- peres. Lamp-board rheostat, for 110 volt circuit, including lamps. Resistance Box, student dial type. Wheatstone bridge, elementary form. 236 Quantity Catalog Unit Total Desired Number Description Price Price . Resistance coils, set of 8. For use with wheatstone bridge. $ $ Single-contact key. Mounted on base 7.5 x 12 cm. . Bell outfit. Complete kit for stu- dent use. — Electrical connectors set com- plete in storage box. . Receptacle for miniature lamps. Miniature incandescent lamp, 2 volts. Switch, knife, single pole, dou- ble throw. 15 amperes. . Switch knife, double pole, dou- ble throw. 15 amperes. Tuning forks, tone alloy, set of four, Give major chord, C. E. G, and C Rubber hammer. Resonance tube, Reservoir type. Complete with support, reservoir and clamps but without tuning fork. Sonometer, universal, all metal, tension key type. . Sonometer wires, set of four. Photometer, Bunsen form, with incandescent lamp source. Com- plete unit. . Foot Candle meter. Photoelectric type. Mirror, plane. 10 x 15 cm. . Mirror support. Mirror, Convex, 50 cm. diameter. Focus 40 cm. Mirror concave, 40 cm. diameter. Focus 40 cm. Refraction bottle complete with instruction. Prism, equilateral. 25 x 100 mm. Demonstration lenses. Set of six. 50 mm. in diameter. Optical bench, standard equip- ment. Complete except for can- dle, lens and mirror. Stevens optical disk. Complete with instructions except for source of light. Optical disk accessories set. Con- tains all lenses and mirrors of above item. Universal course of light, for parallel Rays, 110 to 125 volts. . . 237 Quantity Catalog- Desired Number Description Polaroid experimental kit, lab- oratory all-purpose type. Com- plete with instructions. Tripod Base. Tapped to receive 13 mm. rod. Tripod Base. Tapped to receive 19 mm. rod. Support rods. Diameter. 13 mm. length 40 cm. Support rods. Diameter 19 mm. length 40 cm. Cross Bars, rounded ends. Not threaded. Diameter 13 mm. length 125 cm. Right angle clamp. Two "V" openings at right angles to each other for rods 13 mm. or smaller in diameter. Flush plate or table plate. Small size. Diameter 70 mm. Topped for 19 mm. rod. Screw driver, three-in-one. Soldering iron, electric. Unit Price Total Price Order For Suggested Chemicals From: Name of School Address of School Name of County To: Name of Company Address of Company State Contract No. 334 Charge To: Ship To: Quantity Recommended Ordered Quantity to Order Chemical 1 qt. Acetone 1 lb. Acid, acetic, glacial 1 lb. Acid, acetic, 36% 1 lb. Acid, boric, powd. 6 lbs. Acid, hydrochloric, cone. 7 lbs. Acid, nitric, cone. 4 oz. Acid, oxalic, cryst. 1 lb. Acid, salicyclic, cryst. 1 lb. Acid, Stearic, powd. 9 lbs. Acid, sulfuric, cone. V4 lb. Acid, Tannic 1 pt. Alcohol, amyl 1 gal. Alcohol, ethyl Total Price 238 Quantity Recommended Ordered Quantity to Order Chemical Total Price Alcohol, methyl $ Aluminum chloride, cryst. . Aluminum, turnings Aluminum potassium sulfate, cryst. Aluminum sulfate, gran. Ammonium chloride, cryst. Ammonium dichromate, cryst. Ammonium ferric citrate, gran. Ammonium hydroxide, cone. Ammonium molybdate, cryst. Ammonium nitrate, gran. Ammonium oxalate, cryst. Ammonium sulfate, gran. Antimony, powd. Antimony trichloride, cryst. Barium chloride, cryst. Barium peroxide, anhydrous Benedict's solution Cadmium nitrate, cryst. Calcium carbide, gran. Calcium carbonate, marble chips Calcium chloride, granular, anhydrous Calcium fluoride, powd. Calcium hydroxide, powd. Calcium nitrate, gran. Calcium oxide, lump Calcium sulfate, powd. Carbon disulfide Carbon tetrachloride Charcoal wood, lumps Charcoal, activated Cobalt chloride, cryst. Cobalt nitrate, Cryst. Congo Red, Indicator, Water soluble Copper turnings, light Cupric nitrate, cryst. Cupric oxide, powd. Cuprous oxide, powd. Cupric sulfate, cryst. Dextrose, gran. Ethyl acetate Ethylene glycol Feb ling's solution A Fehling's solution B Ferric chloride, cryst. Ferric nitrate, cryst. Ferrous sulfate, cryst. Ferrous sulfide, lumps. Formaldehyde, 40% Glass Wool, pyrex Glycerine Gum tragacanth, powd. Iodine, cryst, resub. Iron metal fillings, 40 mesh. Lanolin, anhydrous Lead acetate, cryst. Lead nitrate, cryst. Lithium Nitrate, gran. Logwood extract 239 1 Hi- lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 4 lbs. 4 oz. 1 lb. 4 oz. 1 lb. 4 oz. 4 OZ. 1 11). 1 lb. 1 pt. 1 oz. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 11). 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 4 oz. 4 oz. 1 oz. 1 lb. 4 oz. 4 oz. 4 oz. 1 lb. 1 lb. 1 lb. 1 lb. 1 P t. 1 pt. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 4 oz. 1 lb. 4 oz. 4 oz. 1 lb. 1 lb. 1 lb. 1 lb. 4 oz. 4 oz. Quantity Recommended Ordered Quantity to Order Chemical Total Price Magnesium metal, ribbon $ Magnesium sulfate, cryst. Manganese dioxide Mercuric nitrate, powd. Mercurous nitrate, powd. Methyl orange, powd. Oil cocoanut Oil lavender Phenolphthalein, powd. Phosphorus, red, amorphous Potassium Bromide, cryst. Potassium chlorate, cryst. Potassium chloride, gran. Potassium chromate, cryst. Potassium dichromate, cryst. Potassium ferricyanide, cryst. Potassium ferrocyanide, cryst. Potassium hydroxide, pellets Potassium iodide, cryst. Potassium permanganate, cryst. Potassium phosphate monobasic, gran. Potassium thiocyanate, cryst. Potassium sodium tartrate, cryst. Silver nitrate, cryst. Soda lime, 4 mesh. Sodium acetate, cryst. Sodium bicarbonate, powd. Sodium bisulfite, powd. Sodium bromide, gran. Sodium carbonate, cryst. Sodium carbonate, anhyd. Sodium citrate, cryst. Sodium hydroxide, pellets Sodium, metal Sodium nitrate, cryst. Sodium nitrite, gran. Sodium peroxide, gran. Sodium phosphate, monobasic, cryst. Sodium phosphate, tribasic, cryst. Sodium sulfate, cryst. Sodium sulfite, gran. Sodium thiosulfate, cryst. Sodium tetraborate, gran. Stroutium chloride, cryst. Sulfur, flowers Tin metal, mossy Triethanolamine Wax, bees, white Zeolite, gran. Zinc metal, mossy Zinc metal, powd. Zinc chloride, gran. Zinc oxide, powd. Zinc nitrate, cryst. Zinc sulfate, cryst. 240 1 oz. 1 lb. 1 lb. 1 oz. 1 oz. 1 oz. 1 lb. 1 oz. 4 oz. 4 oz. 1 lb. 1 lb. 1 lb. 4 oz. 1 lb. 4 oz. 4 oz. 1 lb. 4 oz. 1 lb. 1 lb. 4 oz. 1 lb. 1 oz. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 2 lbs. 4 oz. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. % lb. 1 lb. % lb. 1 lb. 1 lb. 1 lb. 1 lh. 1 lb. 1 lb. 1 lb. 1 lb. 1 lb. CHAPTER 8— SAFETY IN THE SCIENCE LABORATORY • Safety Committee • Safety Rules • Safety Hazards • Storage of Materials ° Handling of Materials • Faulty Techniques • Electrical Shock • Burns • Toxic Fumes • Poisons 9 Fires • Explosions • Disposal of Wastes 241 Safety in the Science Laboratory Industrial laboratories are generally among the safest places to work. There are several reasons for this. One is that persons working in laboratories have had training which makes a habit of the constant use of safe practices. In addition, they know the nature of the materials with which they are working and thus develop a healthy respect for them. Also, extensive physical provisions are made to insure the safety of workers. Since the fundamentals of safety remain constant once they are learned by the efficient student and teacher, safety habits will govern their actions somewhat automatically. If these conditions hold true for industrial laboratories, why should high school science departments not make the observance of safe practices an inte- gral part of science instruction? Scientific knowledge learned at the expense of eyesight or limb, or accompanied by serious burns or cuts, should not occur at the high school level. Safety Committee What are some of the steps that should be taken to insure a good learning situation and at the same time a safe one ? A safety program must originate with the science teacher, the principal and the superintendent. Since the teacher is the person who will be most familiar with materials to be used and the nature of the work to be accomplished, he is the one from whom specific sug- gestions must come. He is the person who must know how certain chemicals will react under certain conditions ; what experiments are dangerous and which ones should not be performed in the laboratories of his school ; how to use glassware with a minimum chance of getting cut; how to develop within the students a respect for efficient and safe procedures. This is a great deal of responsibility to put on one teacher. Therefore, it is recom- mended that a joint safety program be developed by the science teacher (s) in the school and the other schools in the administra- tive unit, the principals, superintendent, and outside resource persons, such as representatives of fire departments, insurance departments and science related industries. A program of safe procedures for the science departments of each administrative unit should be developed immediately, if such safety procedures have not been made available. Although excellent results are sometimes obtained by admin- 242 istrative units that do not use safety committees, such commit- tees have been notably successful in furthering the cause of accident prevention. A reason for this is that responsibility for accident prevention is given to a specific group and this group can take the steps that are necessary to do its assigned job. Otherwise, the condition may arise in which everyone feels the job is not his. Some of the duties of this committee should be : • Through several thorough examinations during the school year, discover unsafe conditions and practices and determine their remedies. • Discuss and formulate safe policies, recommend their adop- tion by the administrative unit, and see that they are put into practice. Provide opportunity for committee members to learn about safe practices so they may teach them to their students and to other teachers. Safety Rules A set of safety rules posted in the science department gives no assurance that students will observe them. Students need continuous guidance in the selection and use of safe practices. The following "Ten Commandments of Laboratory Safety", prepared by Fisher Scientific Company, should be helpful to the teacher in getting a safety program under way : 1. Think in terms of safe practice constantly. 2. Be familiar with every step of the job you are going to do. 3. Check each apparatus item and chemical at least twice before proceeding. 4. Maintain an awareness of the danger in handling chemi- cals. 5. Remember that the safe way to accomplish a job is the best way. 6. Guard your co-workers' safety and your own. 7. Prepare your counter-attack against possible accidents by forethought. 8. Act promptly and coolly when confronted with an emer- gency. 9. Suggest a safe practice immediately if you see the need for one. 10. Be certain your laboratory has safety equipment and conduct periodic safety meetings. 243 Safety Hazards The dangers of laboratory work are brought about by exposure of the student and teacher to the following hazards : • Storage of materials. • Toxic fumes. ° Handling of materials. • Poisons. • Faulty techniques. • Fires. • Electrical shock. • Explosion. • Burns. • Disposal of wastes. How are high school students and teachers exposed to these hazards and what can be done to insure that experimental work be carried on with a minimum chance of danger to those in- volved? Knowing what is involved in each case is a good way to begin. Storage of Materials The storage of materials used in science work should be pro- vided in two ways. For those materials that are used constantly by all pupils, such as ringstands, beakers, gas burners, tongs, small reagent bottles, etc., it is advantageous to have them stored in the multi-purpose science room or laboratory. This arrangement provides easy accessibility to these materials. It also has a safety factor, because it will prevent the bottlenecks often encountered when a single storeroom is used for all mate- rials. But even this arrangement will produce hazards if the student work space is not designed so that reagent bottles and other materials can be placed on surfaces other than those used for student experimental work, and if the students do not keep their storage units in a clean and orderly condition. There are definite advantages in providing storage of a second type — a separate storage, preparation and special project room. Many materials that are needed for experimental work will not be used more than a dozen times during the year, and in some schools physics apparatus might not be used except every other year. These materials should not be stored at student work areas, because the space will become cluttered and the materials might be damaged. Also, there are pieces of apparatus or certain supplies that the teacher may wish to operate or dispense most of the time, and this can be done better if there is a separate space designated for this purpose. If hazards are to be eliminated in this type of storage room, then it is necessary that the space be designed so that materials can be safely stored. 244 1. There should be windows opening directly to the outside. This will make it possible to have a circulation of air. If there is not enough circulation, then an exhaust fan should be installed. 2. There should be different types of storage. a. Some of the storage can be of the open-shelf type. These shelves should be of the adjustable type in order to provide for materials of various sizes. The base of the shelving should be a section at least six inches high so that nothing will be stored directly on the floor. Items on the floor make housekeeping difficult and present a hazard. Heavy items should be stored on this base. If concentrated acid bottles, such as sulfuric acid, are to be stored on this base, then an inert substance, such as alberene stone, should be placed on top of the wood. When placing items on these shelves, make sure that none extend beyond shelf edge and that no shelf is overloaded. b. A separate unit for storage of chemicals is necessary. The storage of chemicals with physics apparatus may prove to be costly — the apparatus may be damaged by corrosive fumes. c. Some of the storage should be of the lock type. Danger- ous materials, such as deadly poisons, should be kept in this locked case. One section of this storage unit should be reserved for the storage of sodium, potassium, calcium metal and calcium carbide, since they are dan- gerous if water gets to them. It will be well to print on this unit — "In case of fire, do not use water". 3. Good lighting should be provided. No accident should occur because a person cannot see what he is doing. 4. Space should be provided for a fire extinguisher and a sand bucket with small shovel. Fires must be extinguished quickly in this area. There is no substitute for good housekeeping. A department which does not insist on a clean-up after each experiment and periodic house-cleaning in every nook and corner of the depart- ment is well on the road to trouble. As has been pointed out in the first section of this bulletin, this need not be a chore which everyone dreads — it can be made a learning experience. For example, if students become familiar with some of the history 245 and present-day uses of chemicals, they will handle them with more care and will store them in their proper places because of the appreciations which have been developed. Handling of Materials In any science department, it will be necessary to transfer materials from one area to another. To do this in a safe manner, several things must be observed. In the first place, two-liter bottles for such reagents as concentrated sulfuric, hydrochloric and nitric acids should be the largest size containers in the store- room. When these concentrated acids are used, it should not be necessary to carry them a long distance. A preparation counter should be provided in the storage area so these acids can be poured into smaller bottles at that place. Before the bottle is picked up and carried, it should be carefully examined to see if any of the liquid is on the outside (if properly stored, there will be none). A person bringing out materials should have a clear path — no students darting around him and no obstructions on the floor. If he is carrying an item, such as a long piece of glass tubing, he should carry it in a vertical position. Better still, this tubing should be cut into smaller or shorter pieces before being carried about the laboratory. In most instances, this person should be wearing a rubber apron and gloves at all times. If he is carrying chemicals without gloves, it should be standard procedure to wash his hands immediately. One never knows when he might have to put his hands to his face. Minute amounts of some chem- icals can cause serious damage to eyes. A laboratory cart can help in the handling of materials. This will enable one to bring the materials out quickly and safely, with no overloading of one's hands and arms. Be sure the cart is properly loaded. Faulty Techniques Faulty technique is one of the chief causes of laboratory acci- dents, and because it involves the human element, it is one of the most difficult with which to cope. This is particularly true on the high school level, where students have had little previous experience with the techniques involved. The best solution to this problem is the practice of correct procedures by the science teacher. What the student sees and hears, he will likely do in a 246 similar manner. A teacher, then, has no course to follow except the use of the best techniques. Cuts by glassware rank high among accidents in the labora- tory. There are several things which can be clone to minimize this clanger: • No student should be permitted to force glass tubing or thermometers through rubber stoppers. One way to elimi- nate this hazard is to use a cork borer. Select a borer or cutter whose inside diameter is slightly larger than the out- side diameter of the glass tubing. First, thrust the cork borer through the stopper ; second, with the borer inside the stopper, push the tubing through the borer. Then, withdraw the borer leaving the glass tubing in place. • For the thermometer, use a silicone stopcock grease to lubri- cate it before it is inserted in rubber stoppers. • Broken glassware should be discarded immediately. It should not be left on tables or other places, but should be placed in special containers labeled "Broken Glass". • Time is not so important in a laboratory that students should have to use glass tubing that has not been fire polished. A teacher should continually check his technique of heating glass containers and test tubes filled with liquids. To protect against burns while heating a glass container, such as a flask, the laboratory worker should never place his hand under the container. If a student is heating a liquid in a test tube, he should make certain that the open end of the tube is never pointed towards another person. One can never tell when the liquid might pop out of the test tube onto a fellow-worker. To insure further that no one will be injured when these operations are going on, the work area should be free of other persons within a radius of several feet. When handling acids, the following simple rule should be practiced: "Pour acid into water — never pour water into acid". A mnemonic device which may help pupils to remember to pour acid into water may be found in the spelling of "water". Pour the two into the mixing container in the order of the spelling. The "w" for water precedes the "a" for acid. In this connection, it is well to remember that mixing concentrated sulfuric acid with water causes a reaction in which a great deal of heat is generated. 247 Electrical Shock Although all students on the high school level know that wherever there are electrical outlets, wiring or connections, there is danger of electrical shock, this fact should be continually im- pressed on them. It is well to remember that electrical equipment of any type is a potential hazard. The following list presents some of the hazards to be avoided in handling electrical equip- ment: • Handling electrical equipment with wet hands or while standing in wet places. Using improper electrical wiring. e Taking the risk of becoming part of an electrical circuit. • Improper electrical connections. ° Overloading an electrical circuit cr specific length of wiring. Tripping hazards as well as hazards of electrical shock result from excessive and/or improper use of extension cords. • Inserting multiple outlet adapters into regular outlets and thereby permitting several appliances to be plugged into a circuit which may not be adequate for the load. • Using high voltage, such as those encountered in working with step-up transformers, radio or television circuits, with- out benefit of a trained person to supervise the work. (Some TV circuits store electrical energy in such a way that a tremendous shock can be delivered when the set is turned on or off.) A partial solution of these problems involved in electricity is to make a thorough study of them in the physics class and in the 9th grade physical science class. In both of these courses elec- tricity is studied. In addition the students should study their homes as well as the laboratory for possible hazards. In both the laboratory and the home, students should check appliances used, add the wattage (usually indicated on the piece of equipment) to find how many appliances it takes to cause an overload on a single circuit, determine if the number of circuits is adequate, and determine the condition of the appliances or equipment. If conditions are found to be hazardous, then steps should be initiated to remedy this situation. Knowledge gained from such courses should enable students to use safely electrical appliances and equipment. They should know that even the common storage battery can be dangerous — 248 not only because of the acid it contains, but because of the very high current which may be drawn from it on a short circuit. Their increased knowledge should make them aware that all types of induction coils should be clearly marked for the low voltage and high voltage connections in order to avoid the possi- bility of shocks. In many communities there will be a good electrician who will be willing to work with students. Try to secure his services for several class periods, not only to develop some of the important concepts of electricity but also to point out clearly how to elimi- nate hazards associated with the work. Burns There are three types of burns against which students must guard — burns from picking up hot objects, burns from acids and other chemicals and liquids, and burns from gas burners and fires. Many of the burns from hot objects occur because students pick up glassware "that should be cold because it looks cold". A good habit to develop is to bring the hand close to an object but not touching it until it is determined whether it is hot. Whenever practical, laboratory workers should use holders and tongs for picking up many of the items which are being used. Strong acids and alkalies burn human tissue and will destroy it if not washed off immediately. The acids most destructive of human tissue are sulfuric, nitric, hydrochloric; the most corro- sive alkalies are sodium hydroxide, potassium hydroxide, and ammonium hydroxide. Students can get these on their hands or other parts of their bodies and not know it for a short time, depending on the concentration. This frequently happens when a student pours some of the liquid out of the reagent bottle and then puts the bottle back on the shelf without cleaning off the outside. Another student picks it up and gets a burn from the liquid which ran down the side. Similar accidents occur when a student takes a glass stopper out of a bottle and lays it on the table ; some of the liquid is left on the table and a fellow student rubs his arm across it. It should be impressed upon a student that stoppers are never to be taken out of a reagent bottle and placed on the table while he pours out the amount he needs. There is a proper way to do this— the top of the glass stopper being held between the forefinger and middle finger. Severe and very dangerous burns will occur if acids and alka- 24? lies are gotten to the mouth. This accident is very likely to happen if a student uses his mouth on a pipette. This should never be allowed. The safe way is to use a rubber ball or a syringe to aspire the pipette. There are many sources of fires in a laboratory — gas burners, chemicals and electrical circuits. The best way to prevent these fires is to have a good understanding of the capability and the limitations of each. Even though these are well understood, every science department should have one or more fire extinguishers placed in strategic positions and within easy reach and all persons should now how to use them. These extinguishers should be of the compressed carbon dioxide type (carbon tetrachloride and soda-acid type of extinguishers are not recommended for this use) . A regular, frequent inspection, as required by local and State laws, should be made of the extinguishers to insure they are in proper working condition. There is general agreement that nothing is better for fighting a fire in clothing than water and plenty of it. Fortunately, the some thing holds true for acids, caustics and most of the other chemicals that can be splashed in the face or spilled on other parts of the body. This means that a safety shower is a must in a laboratory. A simple, convenient way to provide one is to attach a shower head with approximately six feet of rubber tubing to a special water outlet for this purpose. This arrangement will make it possible to cover a person quickly with a fine spray of water. For the treatment of minor cuts and burns, a first-aid kit is an essential piece of equipment in the laboratory. In addition, there should be a laboratory emergency chart which provides informa- tion on the treatment of burns and scalds, cuts, electrical shocks, and poisons. Several lessons should be devoted to this chart. Not only will the students learn what to do in emergencies, but they will also learn much scientific information. For example, if the chart says to wash burns from strong acids immediately with large quantities of water and then with a 5% solution of sodium bicarbonate, they should understand the scientific basis for this treatment. The same holds true for phosphorus burns which should be covered with a 1% solution of copper sulphate. Toxic Fumes A teacher should think seriously about the matter of having students perform some of the experiments in which poisonous 250 gases are generated. Some of these experiments might well be left to the colleges where they have better facilities to handle them. If the teacher feels that it is necessary to perform the experiment, then several preparatory steps should be taken: Thoroughly understand the nature of the substances being used and the dangers involved. • Use the smallest quantities possible. • Generate the gases in a type of generator which permits little of the gas to escape, such as a Kipp generator. « Plan to do the experiment under a hood. 8 Provide for maximum ventilation. • Have only one small group performing the experiment at any one time. Since students detect some poisonous gases, such as hydrogen sulfide, by their bad odors, they may become complacent and fail to give the proper consideration to the possible deadly effects of these gases ; whereas they will observe safety precau- tions at all times with gases such as carbon monoxide because they realize they cannot readily detect them. Students should not be lulled into security because the gas has a bad odor or because they have generated the gas a number of times — some are poison- ous and should be treated with respect. One technique which all students should develop is the proper way of smelling bottles of gas. The glass stopper should be removed and the other hand used to waft small quantities of the gas to one's nose. A person should never put his nose to the mouth of a bottle — it might contain concentrated ammonium hydroxide, acetic acid, or some other compound with a dangerous and penetrating fume. Poisons In the Safety Education Data Sheets Number 14 called "Chemicals" published by the National Safety Council, 425 North Michigan Avenue, Chicago 11, Illinois, there are these statements: "Most of the common chemicals found in high school laboratories, home chemistry sets, and around the house are not harmful if directions for use are followed, but any of them, if misused, can cause serious injury or death. Therefore, it is essen- tial to understand the possible hazards involved in handling chemicals. 251 "All chemicals are poisonous if taken internally. (Although some are used medicinally, they should be used as such only on a physician's recommendation, and then only in the prescribed dosage.) Poisons can accidentally enter the system by breathing (the vapors and dust of many chemicals are toxic) and by absorp- tion through the skin. Many organic compounds, such as phenol (carbolic acid) and aniline, and some inorganic ones, are rapidly absorbed through the skin; these cause systemic poisoning. Phenol is also very destructive to tissues." Many of the accidents which occur in a laboratory happen because the student erroneously assumes something to be true. Because a beaker contained water only five minutes ago, he may assume that it now contains water. He may assume that a re- agent bottle contains only a very dilute solution of ammonium hydroxide when to his dismay he finds it contains a concentrated solution. Early in the course the teacher must impress on the students that assumptions in the science laboratory can be dangerous. These are some of the precautions to observe in the handling of poisonous chemicals in the laboratory: • Never use a wash bottle for any purpose except to dispense water. • Never drink from a beaker — use the fountain or a paper cup. e Never taste chemicals. • Throw away the contents of unlabeled bottles. 9 Always wash hands immediately after working with poison- ous chemicals. • Label bottles immediately after filling them with solutions. Fires Laboratory fires do not often involve the furniture. They fre- quently originate in making ether, alcohol or naphtha extrac- tions while using a reflux condenser in determining the flash and flame-points of petroleum products and in the careless handling of peroxides, perchlorates, and other compounds having a high percentage of loosely held oxygen. The use of an open flame burner in extractions is an invitation to disaster. Special separate containers should be provided for the disposal of hazardous wastes because these wastes are a likely cause of fires and explosions. Metallic sodium and potassium, various 252 nitrated compounds, and volatile compounds dumped into the sink may cause fires or explosions. Metallic sodium and potassium must be kept under kerosene after the original container has been opened. If the metal is not to be used again for a considerable length of time, it is suggested that it be "buried" in its container in a block of paraffin. Dangerous explosions may result from the presence of organic materials in an oxidizing agent. Care must be taken to avoid exposing chlorates, manganese dioxide, sodium peroxide, or any other oxidizing agents to contamination. When using these sub- stances to prepare oxygen, observe the following precautions: • Make sure there is no chance of mistaking manganese diox- ide for charcoal powder — keep the two far removed. • Do not permit carbon from wood splints to fall into hot potassium chlorate — manganese dioxide mixture. • Do not allow contact of skin with moist sodium peroxide. • Make certain that no active sodium peroxide is left in contact with paper or other easily ignitable substances. • It is suggested that sodium peroxide be handed out to pupils in a dry Erlenmeyer or Florence flask, ready for use. • Water for the reaction with sodium peroxide should be care- fully controlled by a dropping funnel. • Oxygen may be safely prepared from a three or five per cent solution of hydrogen peroxide which is dropped on either powdered manganese dioxide or pelleted activated charcoal. No heat is necessary. Great care must be exercised when using a solution of phos- phorus in carbon disulfide to demonstrate spontaneous combus- tion. The solution should be covered with a layer of water and kept in a small glass stoppered bottle which in turn is stored in a metal container, the bottom of the latter being covered with sand. To use this solution, a medicine dropper is squeezed and inserted below the water into the solution. Since the medicine dropper is contaminated with phosphorus, it constitutes a fire hazard. It should be stored in the same metal can as the solution, being attached to the solution bottle by means of a wire holder. Articles having phosphorus on their surfaces may be made harmless by washing with a solution of copper sulphate. White phosphorus must be kept under water in a double con- tainer, one part of which is metal. This form of phosphorus must 253 be kept only under water. Whenever possible, use red phosphorus in place of white phosphorus. A good point to remember is "fire extinguishers cannot pre- vent fires". Explosions When experiments are to be performed which warrant the use of a face and eye shield and protective clothing, these should be provided and used. If proper techniques are then used, there should be little chance of injury due to an explosion. If an experi- ment requires the use of a number of safety precautions to prevent an explosion, then it should not be performed. In most high school laboratories, hydrogen gas is prepared either by teacher demonstration, by students or by both. If a hydrogen generator is set up for the purpose of showing the gas will burn, never light the gas until : 9 All the air in the generator has been forced out. • A towel has been wrapped around the generator. If a "coke" bottle is filled with hydrogen to illustrate its ex- plosive property, be sure to tape the bottle before the gas is ignited. If hydrogen is to be prepared by putting sodium metal into water, a very small amount of the metal shoud be used. A larger piece can generate enough hydrogen and heat to cause an explosion. In some laboratories not enough precautions are taken when carbon disulphide or ether are being used in experimental work, such as the preparing of rhombic sulphur crystals. Before vola- tile substances, such as these are used in an experiment, a check should be made to see that no Bunsen burners are lighted. In some cases, carbon tetrachloride, a non-combustible liquid, can be used as a solvent instead of a more volatile compound. The preparation of nitrogen by heating a mixture of sodium nitrate and ammonium chloride is likely to produce an explosion if the substances are overheated. Therefore, this method should never be used as a laboratory experiment. If performed as a demonstration, make certain that the solution does not boil. If it does, add water. The preparation of nitrogen iodide should never be attempted by students under any circumstances. 254 Disposal of Wastes A teacher, who understands the hazards, rather than janitors or students, should dispose of dangerous waste materials. A first consideration in this matter is that the teacher and stu- dents should not use materials concerning which they have little or no knowledge — then few wastes will occur that cannot be adequately handled. As a teacher plans his experimental work in advance, he will more than likely come across a few materials that are new to him or about which he can find little information. In this case, he should contact a local chemist, a college chemistry department or the local fire department and obtain the needed information before he proceeds with the experiment. If an indi- vidual student or a group of students plan to do a project in which a number of chemicals will be used, the teacher should "check them out on their understanding of the materials" before they are given permission to begin. The more common waste materials in a high school laboratory are acids, alkalies, broken glass and paper. Before acids and alkalies are poured into the drainage system, they should be neutralized. When this is done, then a quantity of water should be run into the sink to dilute the materials. Special containers should be provided for broken glass and for waste paper. For the safety of the janitor, do not put materials in these containers other than those which are specified. Experimental work is a vital part of all science courses. For- tunately, on the high school level a majority of the experiments are safe. At times the teacher will find it necessary to do some experimental work in which there are potential hazards, but these hazards can be overcome by proper planning and handling. Those experiments which are hazardous unless extreme care is taken should not be performed in the high school science depart- ment. There are limits to the amount and type of work which can be done at this level of instruction and the recognition of this fact will enable schools to provide safe science laboratories. 255 CHAPTER 9— EVALUATION OF THE OUTCOMES OF SCIENCE TEACHING The Purpose of Evaluation Evidences of Purposes Techniques and Instruments to Collect Evidence Interpretation of Evidence Using the Findings 256 Evaluation of the Outcomes of Science Teaching 1 An evaluation of the accomplishments or the extent to which the proposed objectives have been met is an integral part of any teaching procedure. It is often difficult to distinguish between those activities experienced by students for the purpose of acquiring or developing certain skills and understandings, and those experiences provided by the teacher in order to acquire evidence of pupil growth toward the desired outcomes, for the teaching-learning process is not complete without proper evalua- tion. The designer or the carpenter determines his success by the product he produces. He observes closely the craftsmanship, the skill, and the beauty. He tests and retests for use and function- ing ability and carefully checks the finished product with the original plans which served as a guide as the work was done. As his evidence of accomplishments is collected, the designer re-evaluates the tools, methods, and materials used, as well as the conditions under which the product was produced. So it is with the effective teacher, for evaluation is not carried out as a measurement of the facts remembered at the end of a teaching period, but as a well planned program operating continuously throughout the teaching-learning process. In planning and carry- ing out an effective program of evaluation of the outcomes of science teaching, the teacher must consider and plan for five basic aspects of evaluation. THE PURPOSE OF EVALUATION For what purpose am I giving this test ? What type of exami- nation shall I give? Which type of question is best? Can I dis- tinguish between a pupil's growth in the use of laboratory equip- ment and the knowledge gained from the textbook? These are questions which often concern the effective teacher. Their an- swers lie within the basic purposes of evaluation, for valid answers cannot be determined unless the teacher has clearly in mind the reasons for administering various instruments for evaluation. While there are many specific reasons for evaluation, 1 John B. Chase, Jr., A Project in the Cooperative Production of Instruc- tional Guides for Teachers of Science, Unpublished Doctoral Dissertation, The University of Virginia, pp. 160-172. Copyrighted. 257 all may be classified under two basic purposes: (1) to determine the specific accomplishments or outcomes of learning, and (2) to collect information for the diagnosis of problems in the im- provement of the teaching of science. The desired outcomes of a unit of study in science are of four major types: (1) acquired information, (2) understanding of principles or generalizations, (3) changes in attitude toward opinions, evidence, and superstitions, and (4) changes in skills and methods of work, i.e., the way the pupil attacks problems and discovers solutions at each particular time. The purpose may be to determine the extent of acquired information from just one reading assignment, or at the completion of a six-weeks unit of work. The purpose may be to determine whether attitudes have been changed or whether new ones have been developed. The teacher must have the purposes clearly in mind whatever they may be. Diagnosis for the improvement of the teaching of science involves evaluation for the effectiveness of certain methods or the appropriateness of materials used. Evaluation will often reveal the strengths and weaknesses of science offerings and the scope and sequence of content when it is designed to do so. Problems of motivation are often identified. Information col- lected from the analysis of data gained from evaluation designed to reveal the effectiveness of teaching is necessary for wise curriculum change or the improvement of instruction. EVIDENCES OF PURPOSES Once the purposes of evaluation are determined, the teacher must identify what evidence is necessary in order to translate the pre-determined purposes into behavioral change or outcomes. What evidence will reveal acquired information? What evidence will determine understandings rather than memorized data? What evidence will determine the ability of a pupil to solve problems scientifically? For example, the teacher may decide pupils in a particular class should be able to interpret charts and graphs illustrating completely new material as evidence of their ability to draw conclusions. Or, their ability to compare or contrast the life processes of two different animals might ho evidence of acquired information as well as the extent of under- standing. The manner in which a pupil collects data in the 258 laboratory about the effectiveness of certain lubricants in reduc- ing friction between certain metals will reveal evidence of the ability to solve problems scientifically. TECHNIQUES AND INSTRUMENTS TO COLLECT EVIDENCE The development of techniques and instruments which are usable and reliable in the collection of evidence is often difficult and is probably one of the weakest aspects of evaluation in the classroom. The test or instrument which actually measures or causes the pupil to express the evidence which is desired is difficult to produce. There are many standardized commercial tests which may be purchased, but these do not meet the total needs of the classroom teacher. Although it is recommended that commercial tests of achievement and the ability to solve prob- lems be used when appropriate and practicable, techniques and instruments developed by the classroom teacher are most widely used and will always be the center of evaluation in the classroom. Suggestions for evaluating the types of outcomes previously discussed are given below: Acquired Information 1. The traditional types of tests, often called pencil-ancl-paper tests, include objective, short-answer questions and essay questions. These may often be used successfully in meas- uring acquired information. Example: 1. Objective-short-answer questions a. True-False or modified true-false Guides for construction: (1) Avoid ambiguous statements. Use direct state- ments clearly worded. (2) Use approximately an equal number of true and untrue statements. (3) Avoid the use of phrases such as "does not," "the only," "always," and "never" which give clues. (4) It is best to use only one idea in each statement. (5) With a modified true-false test item, the pupil is asked to work out the word or phrase which makes a statement false and to supply the correct word or phrase. True statements are left unchanged. 259 Sample : (1) Bacteria reproduce by dividing. T (2) Bacteria reproduce by fusion, dividing b. Completion: Guides for construction: (1) Items may be either of the sentence or the para- graph type. (2) The "blanks" should call for definite responses. Avoid statements which can be completed by sev- eral correct words. (3) Omit only key-words. Do not omit long phrases. (4) Place the "blanks" near or at the end of the state- ment in order to add continuity in reading. (5) Avoid omitting verbs and adjectives, thus prevent- ing clues and ambiguous guessing. Sample : (1) Malaria is caused by ...?.... protozos c. Modified multiple response Guides for construction: (1) Use at lease five possible responses. (2) All responses should be related to the main thought in order to prevent clues. (3) All responses may be partially-correct answers. In this case the pupil is asked to give the word or phrase which most correctly completes a statement. (4) Include no responses that are obviously wrong. (5) Scatter the correct responses in a different order for each question. (6) Make the beginning statement of the question or problem clear and obvious. The main idea of the problem should be specific. (7) If a correct response is not given, the pupil is asked to write in the correct response. Sample : (1) DDT is a powerful (a) antibody; (b) insecticide; (c) antibiotic; b (d) disinfectant; (e) germicide. (2) DDT is a powerful (a) antibody; (b) disinfectant; (c) vaccine; insecticide (d) antibiotic; (e) germicide. 260 d. Matching: Guides for construction: (1) Use only homogeneous or related materials in any one exercise. (2) Include at lease three to five extra choices from which responses must be chosen. ■ (3) Place the column containing the longer statements on the left side of the page. (4) Use illustrations or items which explain whenever possible. Sample : Column I Column II C 1. restores fertility to the soil A. photosynthesis E 2. product of living organisms B. inorganic matter used to conduct pathegenic C. nitrogen cycle organisms. D. toxin D 3. poison produced by E. antibiotic certain organisms. F. chlorophyll G. antibody e. Essay Questions : Essay questions are successfully used to ask the pupil to compare or contrast, classify, illus- trate, discuss, show effects, criticize, apply, define, out- line, and summarize. This type of question may be used successfully in measuring acquired information and the understanding of principles or generalizations. Sample: (1) What is the difference between active and passive immu- nity ? (2) Describe (a certain number) ways by which bacteria help us? or harm us? (3) (Present to the pupils data of the epidemics in an area during a certain period of time.) From the date presented, what do you think is likely to happen to the number and types of epidemics in X (community, county, state, nation) within the next five years? (4) List and discuss the characteristics common to all proto- zoa? Algae? (5) A demonstration may be performed, and questions directly related to the experiment may be asked. As an example, 261 an experiment which illustrates the conditions necessary for the growth of bacteria may be conducted. Afterwards, pupils may be asked: (a) Why were the cultures placed in varying conditions? (b) Under what conditions were the cultures placed? (c) Did you note any differences in the rate of growth when one-half of the cultures were exposed to sun- light and the other half to darkness? Describe any differences. (d) Just what does this demonstration show? What can you conclude from it? (e) Show how the points which you actually observed and those which you assumed helped you to arrive at your conclusions. (See d) (f) From this experiment, what applications may be drawn concerning: The use of refrigeration in preserving foods, the storage of bread, the use of disinfectants in the home ? Changes in Attitude 1. A self-rating scale on attitudes: A rating scale may be given to pupils by the teacher two or more times during the study of the unit. It is particu- larly helpful to use a rating scale at the beginning of the study of a unit, thus enabling the teacher to help pupils correct attitudes in which their rating is low. The ratings will also provide an excellent basis for individual confer- ences. The scale may be used again at the conclusion of the study. This procedure helps the pupil and teacher to determine the extent of change. If the teacher is aware of the background of pupils and the community, certain atti- tudes, opinions, beliefs, and superstitions which exist in the locality can be used in constructing a check list to be used by the teacher. Example : Mark each statement: "T" — I do believe, "U" — Undecided, or "F" — I do not believe. 262 T U F 1. Certain charms of good luck prevent many diseases. . . 2. Mr. James died of T.B. ; therefore, it is evident that other members of his family will catch T.B. . 3. If Mr. Black's lake is polluted and dirty, it is his responsibility and also, it should be of concern to the community. . . 4. Both adults and children need vacci- nations. . . 5. The community health department is very expensive and should be reduced in operation, for it is the responsibility of the individual to care for his health. 6. Bacteria cause disease; therefore, bacteria should be destroyed. . . 2. Observation: Teachers can readily find evidence of the extent to which certain pupils develop and change attitudes by carefully planned observation. It is suggested that the teacher look for these changes and record descriptions of situations which illustrate certain attitudes. An index card or a pre- pared form will be convenient for this purpose. The following list may serve as guides when observing pupils : (name of pupil) (date) 1. Does the pupil base opinions on adequate evidence? Situation: The group working on certain modern drugs was concerned about the use of a specific drug. There were different opin- ions expressed. Pupil Action: Doug used only one popular magazine article as evidence of the effectiveness of the drug. 263 (name of pupil (date) 2. Does the pupil revise opinions in light of new evidence? Situation: During yesterday's discussion Jack ex- pressed the opinion that "X-Y" an anti- septic, was absolutely not effective. Other pupils questioned his opinion. When asked how the problem could be solved, many suggestions were made. Pupil Action: At home that evening Jack checked sev- eral references without being asked to do so. Today he planned and conducted an experiment to help solve the problem. His conclusions changed his opinions. (name of pupil) (date) 3. Does the pupil listen to, read about, or observe evidences contrary to his own opinions? Situation: (see above illustration) Pupil Action: 4. If two events happen at the same time, does the pupil believe there is a necessary connection between the two ? 5. Does the pupil jump to conclusions? 6. Does the pupil exaggerate or does he stick to facts? 7. Is the pupil slow to accept as facts ideas not supported by evidence ? 8. Is the pupil satisfied with vague explanations ? A careful analysis of the pupil's projects, oral and written reports, readings, notebooks, and drawings will reveal valuable evidence of attitudes. Changes in Technique or Method of Work An analysis of the pupil's work when solving problems will give evidence of his ability to use the scientific method, as well as evidence of the understanding of principles or generalizations. Example: 1. An experiment is performed to illustrate the effects of certain disinfectants and antiseptics on bacterial growth. 264 As suggested in the list of activities, to one culture add lysol, to another add hydrogen peroxide, to another add carbolic acid, to another add listerine, and use one as a control. Observe at different intervals of time. Ask the pupil to: a. Describe briefly the problem. b. Describe the steps involved. c. Report main observations. d. Report control steps. e. Draw conclusions. On the basis of this report, to what extent can the pupil : a. Identify or describe a problem? b. Observe and report accurately all steps involved? c. Observe and report accurately significant changes or evidences? d. Draw conclusions consistent to the problem and evi- dence produced? 2. In the above example the pupil observed an experiment which was demonstrated. As another example, the pupil could be given a similar problem and all methods and tech- nique to be used left for his decision. The pupil can select his own problem, or one may be assigned to him. The solu- tion is left to the planning and direction of the pupil. To what extent can the pupil plan and set-up the experiment and to what extent does he utilize all available resources to solving the problem? An analysis of the report made by the pupil will give evidence of his ability to plan and con- duct such a prbolem. INTERPRETATION OF EVIDENCE After the teacher has collected evidence of the degree of ac- complishment or the extent to which objectives have become outcomes, the interpretation of the findings become important. What does this score mean? Is it possible to place a score of value upon this type of finding? Does this evidence illustrate progress, growth, or achievement? Questions of this type become important in the interpretation of evidence once it is collected. The following suggestions will be helpful in making interpre- tations : (1) Determine the span of the evidence collected. For ex- ample, determine the level of achievement of pupils before 265 the study began in relation to the evidence collected at the completion of a unit of study. (2) Determine the value of the evidence in relation to the predetermined purposes. For example, does this evidence express a change in behavior or thinking in relation to the purposes of the study. (3) Compare evidence collected with individual abilities of pupils as expressed on intelligence tests and achievement tests of reading and arithmetical abilities. (4) Prepare tables which illustrate the frequency individual items of evidence were expressed, observed, or missed. (5) Record evidences which show change or certain patterns of behavior over a long period of time. Look for individual patterns rather than isolated evidence. (6) Compare evidence collected with reading level of mate- rials used for teaching, the reliability of references used, and the relationship of evidence to the experiences in the classroom. (7) Compare the evidence collected with the behavior of pupils outside the classroom. Is there any transfer? (8) Compare the evidence collected with methods used in the classroom. For example, does the evidence of the ability of the pupil to identify problems relate to the methods used in the classroom when identifying problems? (9) Relate evidence to the interests and needs of individual puplis. (10) Relate evidence collected in the school setting to life experiences of individual pupils. The above suggestions are by no means complete, but will be of help to the classroom teacher when making judgments or measurements of the achievements of pupils, as well as of the effectiveness of teaching. USING THE FINDINGS The evaluation process is not complete until findings have been used for the improvement of learning and teaching. For example, an interpretation of certain evidences collected caused the teacher to conclude that pupils cannot solve problems which are pre- sented in a laboratory situation, even though they may be able 266 to answer questions about problems presented in the textbook. Therefore, the teacher decides to place more emphasis upon the solution of problems in the laboratory rather than upon the mere discussion of problems solved in the text. The use of findings may lead to changes in scope and sequence of content as well as changes in the grouping of pupils. New courses may be added, and existing ones may be expanded to include newer concepts. Proper use of findings often leads to a better selection of textbooks and other reading materials. The number of failures is reduced and problems of motivation are solved. The use of findings from programs of evaluation will vary from school to school, but there is little doubt that much could be accomplished in the improvement of instruction, the growth and self-understanding of pupils, and in the enrichment of the science curriculum by the study and use of evidences of evaluation. Evaluation is not an isolated factor in the teaching-learning process, but is most effective when carried on constantly during the teaching of a unit rather than only at the conclusion of the unit. Teaching can find many opportunities for evaluation avail- able when pupils are actively involved in scientific experiences rather than in passive listening. 267 CHAPTER 10— READING MATERIALS FOR STUDENTS AND TEACHERS • Point of View • Bibliography for High School Biology • Books of the Traveling High School Science Library 263 Reading Materials for Students and Teachers POINT OF VIEW Effective science teaching and learning in our modern world require the use of many instructional materials. The classroom which utilizes a variety of instructional materials provides a rich learning environment. Boys and girls who are surrounded by such materials, who are encouraged to locate and use them, are gaining valuable experiences in the habit of personal investiga- tion. They are gaining skills in using books and libraries in order to locate needed information, to satisfy personal interests and as a means of pleasure in reading. "While science is more than the objects around us, it begins with the objects. It deals with the nature of materials and the energy of the universe and with their interrelationships. It deals with the effect of this knowledge on us and the ways that we can use it. Our knowledge of the world around us has, in general, been recorded in written form for purposes of communication — communication to others now and later. Essential as the written form is, its misuse has created some of our most difficult teach- ing problems. "There has been a ready assumption that reading about mate- rials and energy is equivalent to experience with these aspects of the world around us. This is not the case. We cannot have first-hand experience through reading, although there is an op- portunity for vicarious experience in this way. Some basic first- hand experience is essential ; some teaching aids are essential ; some reading is essential. It is the task of the science teacher to find the balance among them ; then to find and use wisely the most effective resources and procedures available". 1 There are many fine books on all phases and levels of science, its applications, its philosophy, its implications and its teaching. The science teacher has available increasing quantities of poten- tially valuable printed materials and is faced with the problem of choosing them wisely. Students may be discouraged from or attracted to science, or they may learn or not learn in part be- cause of the quality of the reading materials. The school librarian can be of invaluable assistance in finding and choosing books, but 1 Richardson, John S., Science Teaching in Secondary Schools, Englewood Cliffs, N. J. Prentice-Hall, 1957, p. 256. 269 the careful attention of the science teacher to the problem of selection is most desirable. The list of science books should include some of popular inter- est as well as those of a more informational nature. The supple- mentary reading corner should enable students interested in a particular phase of science to read further — dinosaurs, elec- tricity, photography, space travel, astronomy or human behav- ior. Books should be chosen for their stimulation and general suitability for use in the secondary school. Differences in learn- ing rate should be kept in mind in making the selections; stu- dents with various levels of ability should find books with ideas and presentations appropriate to their levels. As examples of books which have been selected with the fore- going in mind and which may be used to guide the science teach- er in his thinking as he goes about building an adequate and challenging science library, two lists of books are given. A group of Wake County teachers compiled the list for biology, whereas a National group of scientists and teachers, as noted therein, brought together the titles in the traveling science library. An excellent topical bibliography for a science library, in- cluding some titles of a professional nature, is found in A Source- book for the Biological Sciences, 2 but the most complete and com- prehensive list of professional aids is Resource Literature for Science Teachers/' A few of the professional books listed are: Beck, W. Modern Science and the Nature of Life. Harcourt, Brace & Company, 1957. Brandwein, P. et al. Teaching High School Science: A Book of Methods. Harcourt, Brace & Co., 1958. Burnett, R. Will. Teaching Science in the Secondary School. Rinehart and Company, Inc., 1957. Butterneld, H. The Origins of Modern Science, 1300-1800. Mac- millan, 1951. Craig, O. S. Science for the Elementary School Teacher. Ginn, 1958. Freeman, K., et al. Helping Children Understand Science. Win- ston, 1954. Gabriel, M., and S. Fogel, eds. Great Experiments in Biology. Prentice-Hall, 1955. 2 Morholt, Brandwein & Joseph. Teaching High School Science : A Source- book for Biological Sciences, N. Y. Harcourt, Brace & Co., 1958, pp. 453-462. 3 Richardson, John S., ed., Resource Literature for Science Teachers, Co- lumbus, 0., Ohio State U. Press, 1957. 270 Goldstein, P. How to do an Experiment. Harcourt, Brace & Co., 1957. Greene, W., and H. Blomquist. Flowers of the South, UNC, Chapel Hill, 1953. Joseph, A., et al. Teaching High School Science: A Sourcebook for the Physical Sciences. Harcourt, Brace, 1959. National Education Association. Science in Secondary Schools Today. Bull. Nat. Assoc. Secondary School Principals, Wash- ington, D. C, January, 1953. Richardson, J., and G. Cahoon. Methods and Materials for Teach- ing General and Physical Science. McGraw-Hill, 1951. United States Atomic Energy Commission. Laboratory Experi- ments with Radioisotopes for High School Science Demon- strations. Washington, D. C, 1953. There is an abundance of science reading material available through business and industry which has been greatly improved in recent years and has considerable potential value for teaching science. The wise science teacher will choose the best of the materials that are available and not lose his sense of perspective with respect to business-sponsored materials so that undue em- phasis is given, or the educational program thrown out of bal- ance. The stock of materials should be kept up to date with an adequate filing system in operation so they are readily accessible. Several annotated lists of sources of such materials are avail- able in various publications, two of which are : Richardson, John S., Op. Cit., pp. 261-299. Morholt, et al. Op. Cit, pp. 475-478. BIBLIOGRAPHY FOR HIGH SCHOOL BIOLOGY Animal Ecology Ditmars. Strange Animals I Have Known. Harcourt, 1931. Lorenz. King Soloman's Ring. Crowell, 1952. Mason. Animal Sounds. Morrow, 1948. Mason. Animal Tools. Morrow, 1951. Mason. Animal Weapons. Morrow, 1949. Anthropology Edel. Story of People. Little, 1953. 271 Bacteriology Schatz. Story of Microbes. Harper, 1952. Beavers Conibear. Wise One. Sloane, 1949. Birds Audubon. Birds of America. Macmillan, 1946. Dupuy. Our Bird Friends and Foes. Winston, 1940. Forbush and May. Natural History of the Birds of Eastern and Central North America. Houghton, 1939. Hickey. A Guide to Bird Watching. Doubleday, 1953. Howard. Birds as Individuals. Doubleday, 1953. Kieran. Introduction to Birds. Garden City Books, 1950. Kortwright. Ducks, Geese, and Swans of North Carolina. Wild- life Management Institute, 1942. Lemmon. Our Amazing Birds. Doubleday, 1952. Lincoln. Migration of Birds. Doubleday, 1952. Murray. Wild Wings. John Knox Press, 1947. Pearson and others. Birds of America. Garden City Books, 1949. Pearson and others. Birds of North Carolina. N. C. Department of Agriculture, Raleigh, N. C, 1942. Peterson. Field Guide to the Birds. Houghton, 1947. Pough. Audubon Water Bird Guide. Doubleday, 1951. Pough. Audubon Bird Guide; Small Land Birds of Eastern and Central North America. . . Doubleday, 1949. Saunders. Lives of Wild Birds. Doubleday, 1954. Zim and Gabrielson. Birds (guide). Simon and Schuster, 1949. Botany Conrad. How to Know the Mosses. Brown, W. C, 1944. Dupuy. Our Plant Friends and Foes. Winston, 1948. Felt. Plant Galls and Gall Makers. Comstock Publishing Asso- cites, 1940. Smith. Fresh Water Algae of the United States. McGraw, 1950. Zim. Plants. Harcourt, 1947. Botany — Economics Clute. Usefid Plants of the World. W. N. Clute, 1943. 272 Butterflies and Moths Holland. Butterfly Book. Doubleday, 1931. Klots. Field Guide to the Butterflies of North America, East of the Great Plains. Houghton, 1951. Ecology Andrews. Nature's Ways. Crown, 1951. Storer. The Web of Life. Devin, 1953. Evolution Moore. Man, Time, and Fossils. Knopf, 1953. Ferns Blomquist. Ferns of North Carolina. Duke University Press, 1934. Fishes Emmens. Keeping and Breeding Aquarium Fishes. Academic Press, 1953. Innes. Exotic Aquarium Fishes. Innes Publishing Co., 1950. National Geographic Society. Book of Fishes. National Geo- graphic Society, 1952. Flowering Plants Carey. Wild Flowers at a Glance. Pellegrini and Cudahy, 1950. Clements. Flowers of Prairie and Woodland. H. W. Wilson, 1947. Green and Blomquist. Flowers of the South. University of North Carolina Press, 1953. Hausman. Beginner's Guide to the Wild Flowers. Putnam, 1948. Johnston. Macmillan Wild Flower Book. Macmillan, 1954. Kieran. Introduction to Wild Flowers. Garden City Books, 1952. Mathews. Field Book of American Wild. Flowers. Putnam, 1929. Wherry. Wild Flower Guide. Doubleday, 1948. Zim. Flowers (guide). Simon and Schuster, 1950. Frogs, Toads Wolfson and Ryan. The Frog. Row, Peterson. Wright. Handbook of Frogs and Toads of the United States and Canada. Comstock Publishing Associates, 1949. 273 Fungi Christensen. Common Edible Mushrooms. University of Minne- sota Press, 1947. Thomas. Field Book of Common Mushrooms. Putnam, 1948. Genetics, Heredity Scheinfield. New You and Heredity. Lippincott, 1950. Geology (Physical and Dynamic) Schneider. Rocks, Rivers and the Changing Earth. Scott, W. R., 1952. Grasshoppers Bronson. Grasshopper Book. Harcourt, 1943. Insects Borror and De Long. An Introduction to the Study of Insects. Rinehart, 1954. Comstock. An Introduction to Entomology. Comstock Publish- ing Associates, 1940. Curran. Insects in Your Life. Sheridan, 1951. Fabre. Insect Adventures. Dodd, 1950. Gaul. Wonderful World of Insects. Rinehart, 1953. Harpster. Insect World. Viking, 1947. Insects. The Yearbook of Agriculture, 1952. Superintendent of Documents, Washington, D. C, 1952. Lutz. Field Book of Insects of the United States and Canada. Putnam, 1935. Needham and Westfall. Manual of the Drag onf lies of North America. University of California Press, 1954. Neider. The Fabulous Insects. Harper, 1954. Peterson. Larvae of Insects, Part I. Edward Brothers, Inc., 1951. Peterson. Larvae of Insects, Part II. Edward Brothers, Inc., 1951. Ross. Insects Close Up. University of California Press, 1953. Stawell. Fabre's Book of Insects. Tudor, 1939. Swain. The Insect Guide. Doubleday, 1948. Teale. Junior Book of Insects. Dutton, 1953. Westcott. The Gardener's Bug Book. Doubleday, 1946. Zim and Cottam. Insects (guide). Simon and Schuster, 1951. 274 Buchsbaum. Animals Without Backbones. University of Chi- cago Press, 1950. Wolf son and Ryan. The Earthworm. Row, Peterson, 1955. Mammals Bridges. Wild Animals of the World. Garden City Books, 1948. Burt. A Field Guide to Mammals. Houghton, 1952. Palmer. The Mammal Guide. Doubleday, 1954. Wolfson and Ryan. The Human. Row, Peterson, 1955. Microscopy Hawley. Seeing the Invisible. Knopf, 1945. Mineralogy Loomis. Field Book of Common Rocks and Minerals. Putnam, 1948. Pough. Field Guide to Rocks and Minerals. Houghton, 1953. Mollusca and Molluscoidea Morris. A Field Guide to the Shells. Houghton, 1951. Rogers. Shell Book. Branford, 1951. Verrill. Shell Collector's Handbook. Putnam, 1950. Nature Study Comstock. Handbook of Nature Study. Comstock Publishing Associates, 1939. Hillcourt. Field Book of Nature Activities. Putnam, 1950. Jordan. Hammond's Guide to Nature Hobbies. Hammond, 1953. Jordan. Hammond's Nature Atlas of America. Hammond, 1952. Palmer. Fieldbook of Natural History. McGraw, 1949. Parker. Golden Treasury of Natural History. Simon and Schuster, 1952. Peterson. Wildlife in Color. Houghton, 1951. Wells. Natural Gardens of North Carolina. University of North Carolina Press, 1931. Oceans and Oceanography Carson. The Sea Around Us. Oxford, 1951. Carson. Under tine Sea Wind. Oxford, 1952. 275 Paleontology Baity. America Before Man. Viking, 1953. White. Prehistoric America. Random House, 1951. Reproduction (Embryology) Hamilton. Lillie's Development of the Chick. Holt, 1952. Patten. Early Embryology of the Chick. Blakiston, 1951. Rugh. Experimental Embryology. Burgess, 1948. Reptiles Ditmars. Reptiles of North America. Doubleday, 1936. Ditmars. Reptiles of the World. Macmillan, 1933. Zim. Reptiles and Amphibians. Simon and Schuster, 1953. Snakes Ditmars. Snakes of the World. Macmillan, 1931. Morris. Boys' Book of Snakes. Ronald, 1948. Spiders Gertach. American Spiders. Van Nostrancl. Lamburn. Life of the Spider. Houghton, 1951. Taxidermy Anderson. Methods of Collecting and Preserving Vertebrate Animals. National Museum of Canada, 1948. Pray. Taxidermy. Macmillan, 1953. Trees Collingwood. Knowing Your Trees. American Forestry Asso- ciation, 1947. Coker and Totten. Trees of the Southeastern States. University of North Orolina Press, 1937. Emerson and Weed. Our Trees; How to Know Them. Lippin- cott, 1946. Hylander. Trees and Trails. Macmillan, 1953. Kiernan. An Introduction to Trees. Hanover House, 1954. Mathews. Field Book of American Trees and Shrubs. Putnam, 1915. Trees. The Yearbook of Agriculture, 1949. Superintendent of Documents, Washington, D. C, 1949. Zim. Trees (guide) . Simon and Schuster, 1952. 276 Zoogeography — Marine Fauna Barton. World Beneath the Sea. Crowell, 1953. Beebe. Exploring with Beebe. Putnam, 1932. Carson. Under the Sea Wind. Oxford, 1952. Coker. Streams, Lakes, Ponds. University of North Carolina Press, 1954. Hausman. Beginner's Guide to Fresh Water Life. Putnam, 1950. Miner. Field Book of Seashore Life. Putnam, 1950. Neeclham and Needham. Guide to the Study of Fresh Water Life. Comstock Publishing Associates. Zoology Hogner. Parade of the Animal Kingdom. Macmillan, 1935. Jahn. How to Know the Protozoa. Brown, W. C, 1949. BOOKS OF THE TRAVELING HIGH SCHOOL SCIENCE LIBRARY 4 The Traveling High School Library Program is supported by a grant from the National Science Foundation and is adminis- tered by the American Association for the Advancement of Sci- ence. The program reflects the great interest of both agencies in assuring sufficient scientific manpower for the future and recog- nizes that most careers in science and mathematics actually begin during the period of high school education. The majority of the high school students in the United States live in commu- nities where neither the school library nor the public library, if there is one, afford adequate opportunity for recreational or collateral reading in the sciences and mathematics. The general purposes of the Traveling High School Science Library Program are to stimulate an interest in reading science and mathematics books, to broaden the science background of high school students, and to assist students who have interests in science and mathematics in choosing professional careers in the sciences. Though not a primary objective, the Program ac- quaints high school teachers and librarians with well-written and interesting books on science and mathematics which are suitable for general reading by high school students and which would be appropriate acquisitions for the school or community library. 4 American Association for the Advancement of Science. High School Traveling Science Library Program, Washington 6, D. C. 277 Biographies and autobiographies, histories of science and mathematics, and books on applied science are well represented in the collection. An attempt has been made to provide a very broad range of subject-matter so that a high school student may have an opportunity to acquaint himself with the major branches of science and to discern the practical application of the sciences and mathematics in research, in the professions, and in industry. As a rule, textbooks have not been selected ; the few that are included were chosen because no trade books were available that covered the same subject adequately. Most of the books have been chosen because of their appeal to the general reader who has little or no background in science and whose proficiency in mathematics does not go beyond elementary algebra and plane geometry. A few books are somewhat more advanced and will provide an incentive to the exceptional high school student. Agriculture Archer, Sellers G. Soil Conservation. Univ. of Oklahoma Press, 1956. The history, principles, and practice of soil conservation are authorita- tively presented for the enlightment of all good citizens irrespective of their interest in agriculture. Kellogg, Charles E. The Soils That Support Us. Macmillan, 1951. Traces the development of soil science. Sears, Paul B. Deserts on the March. Univ. of Oklahoma Press, 1947. Man's nutrition, agriculture, commerce, industry and science are pre- sented in their related whole so we may understand the soil and how important it is. Storck, John, and Walter D. Teague. Flour for Man's Bread: A History of Milling. Univ. of Minnesota Press, 1952. The ways in which man has made flour for his bread have forged the patterns of technological progress: the refinement of tools, the increas- ing use of power, the development of large scale production and distri- bution. Anatomy Carlson, Anton J., and Victor Johnson. The Machinery of the Body. Univ. of Chicago Press, 1953. A book on human physiology for the layman which explains the me- chanics and machines of the body, their operation, and their raw ma- terials and products. Sproul, Edith E. The Science Book of the Human Body. Watts, 1955. This simple, well-illustrated book on the anatomy and physiology of the human body presents facts which everyone should know and under- stand. 278 Anthropology Bates, Marston. The Prevalence of People. Scribner, 1955. The problems of population, epidemic disease, survival, increased lon- gevity and food supplies are discussed as a related whole. Benedict, Ruth. The Chrysanthemum and the Sword. Houghton, 1946. The cultural differences between Japanese and Occidentals are corre- lated with unique cultural traditions, socio-economic and religious back- ground, and other factors. This book gives an acquaintance with the subject matter and methods of cultural anthropology. Dobzhansky, Theodosius. Evolution, Genetics, and Man. Wiley, 1955. The basic principles of evolution and heredity are presented in terms intelligible to anyone who has had a course in high-school biology. Hooton, Earnest Albert. Up from the Ape. Macmillan, 1946. The story of the evolution and inheritance of man from his long line of historic ancestors. Also a comparative study of living types of men. Howells, William. Back of History: The Story of Our Own Origins. Doubleday, 1954. An understandable story of the human background. Macgowan, Kenneth. Early Man in the New World. Macmillan, 1953. Earthquakes, changes in the land masses of the world, and the effects of glaciers are related to the dispersal of man throughout the world, to his survival, and to the development of racial differences. Archaeology Cottrell, Leonard. The Mountains of Pharaoh. Rinehart, 1956. A history of the pepoles who built the pyramids, and of the diggers who have explored their inner recesses. Cousteau, J. Y. The Silent World. Harper, 1953. An account of underseas experiences: probing long-forgotten ship- wrecks, destroying mines set during the war, finding sunken treasures of past centuries, and viewing underseas life in its own world. Ceram, C. W. Gods, Graves, and Scholars: The Story of Archae- ology. Knopf, 1954. A popular story of the search for facts concerning the peoples of Pompeii, Troy, Mycenae, Crete, Egypt, Assyria, Babylonia, Sumeria, and the Empires of the Toltecs, Aztecs, and Mayas. Diamond, Freda. The Story of Glass. Harcourt, 1953. A story of the discovery, making, and fabrication of glass to meet its many uses. Diole, Philippe. 4000 Years Under the Sea. Messner, 1954. An account of the discoveries of skin divers and helmet divers, who have recovered from the deep sea world many remnants and treasures of past centuries. White, Anne Terry. Lost World: The Romance of Archaeology. Random House, 1941. Accounts of discoveries and discoverers of ancient Troy, Mycenae, Crete, Egypt, Assyria, Babylonia, Sumeria, and the ancient Mayas. 279 Architecture Townsend, Gilbert and J. Ralph Dalzell. How to Plan a House. American Technical Society, 1952. This book shows the operations an architect must carry out in designing a house, drafting its specifications, and supervising its construction. Astronomy Alter, Dinsmore and C. H. Cleminshaw. Pictorial Astronomy. Crowell, 1952. Charts show the principal constellations from pole to pole from month to month throughout the year. Bonestell, Chesley, and Willy Ley. The Conquest of Space. Vik- ing, 1956. Presents the basic knowledge and discoveries of astronomy, mathematics and physics upon which will rest man's eventual achievement of inter- planetary flight. Gamow, George. The Moon. Schuman, 1953. The many phases of moon sciences: legend, history, origin, romance, discovery, "moon geology," and the possibility of travel to the moon. Levinger, Elma Ehrlich. Galileo: First Observer of Marvelous Things. Messner, 1954. Galileo, who devoted his life to philosophy, mathematics, and astronomy, revised current notions of gravity and became an experimental scientist searching for honest truth. Lay, Willy, and Wernher Von Braun. The Exploration of Mars. Viking, 1956. We are told how engineers and other scientists, building upon the foundation of the astronomers, have planned the details of a possible flight to Mars for the first-hand exploration of that planet. Moore, Patrick. The Story of Man and the Stars. Norton, 1955. The origin and development of the modern science of astronomy. Payne-Gaposchkin, Cecilia. Stars in the Making. Harvard Univ. Press, 1952. A presentation of the drama of the heavens in the three acts : Ages of Things, Evolution of Galaxies, and Evolution of Stars. Pfeiffer, John. The Changing Universe. Random House, 1956. A description of a new field of research, "radio astronomy," which is exploring a new universe by means of radio signals and radio objects. Smart, W. M. The Origin of the Earth. Cambridge Univ. Press, 1953. A record of the contributions of astronomy, physics, chemistry, geology, and biology to our knowledge of how the earth came into existence. Woodbury, David O. The Glass Giant of Palomar. Dodd, 1954. The book describes the great telescopes of the world: in particular, the giant one on Mount Palomar in California. Atomic Science Asimov, Isaac. Inside the Atom. Abelard-Schuman, 1956. A famous scientist explains atomic energy in a simplified manner, be- ginning with the structure of matter and building up to atomic energy itself. 280 Dean, Gordon. Report on the Atom. Knopf, 1954. The former chairman of the Atomic Energy Commission writes that anyone should know about the atomic energy program of the United States — facts that are needed for survival in the atomic age. Fermi, Laura. Atoms in the Family: My Life with Enrico Fermi. Univ. of Chicago Press, 1954. The story of the life of Enrico Fermi as student, teacher, and finally as foremost research worker in atomic physics. An informal narrative, written by Dr. Fermi's wife. Gamow, George. Mr. Tompkins Explores the Atom. Cambridge Univ. Press, 1955. The development of our hero (Mr. Tompkins) of what he believes to be a sure-win gambling system becomes the route for understanding mole- cular motion, statistical fluctuations, and other phenomena. Glasstone, Samuel. Sourcebook on Atomic Energy. Van Nos- trand, 1950. Here, in one book, is summarized all present knowledge of atoms, atomic theory, and atomic science. Hecht, Selig. Explaining the Atom. (Revised and enlarged by Eugene Rabinowitch) . Viking, 1955. The story of the atom is unfolded in stages or events, each arising out of those that have preceded it: The atom as a homogeneous ball. The atom becomes complex. The atom develops a structure. Atoms release energy. Atomic bombs become possible. Atomic bombs are made. Atomic bombs become plentiful and varied. "Superbombs" are built. Atomic power emerges. Kugelmass, J. Alvin. ./. Robert Oppenheimer and the Atomic Story. Messner, 1953. This is the story of a still young scientist who had much responsibility for building the atomic bomb, and for releasing atomic energy for peacetime and useful purposes. Everyone should know the facts pre- sented by this popular insight into atomic science. Aviation Bonestell, Chesley, and Willy Ley. The Conquest of Space. See entry under Astronomy, p. 280. Combs, Charles. Skyrocketing into the Unknown. Morrow, 1954. The principles and mechanics of rocket and jet airplanes are described for the layman in this well-illustrated book. Holland, Ray, Jr., The Physical Nature of Flight. Norton, 1951. Word-picture diagrams are used to explain the laws of motion and principles of aerodynamics. Important factors in airplane design and construction are well explained. Kaplan, Joseph, et al. Across the Space Frontiers. Viking, 1953. The scientific and experimental background upon which flight can be based is absorbingly related as a prelude for space travel. Then comes a discussion of the problems of man's survival in space. Upon these bases scientifically plausible designs are suggested for "space stations" and ships for interplanetary travel. Ley, Willy, and Wernher Von Braun. The Exploration of Mars. See entry under Astronomy, p. 280. 231 Morris, Lloyd, and Kendall Smith. Ceiling Unlimited: The Story of American Aviation from Kitty Hawk to Supersonics. Macmillan, 1953. The authors follow aviation through early development, two world wars, and into one of the chief present-day modes of mass transportation. Murchie, Guy, Jr., Song of the Sky. Houghton, 1954. This book describes great explorations that developed the science of navigation, discusses the phenomena of weather, and shows how aviation and flight formations copy the ways of birds. It goes on to consider magnetism, sound barriers, and opportunities for new adventures in the heavens. Rodahl, Kaare. North: The Nature Drama of the Polar World. Harper, 1953. The story of the first landing on an ice island near the North Pole, thus establishing a base for scientific investigation of the North Polar Basin — an important step in the development of transpolar aviation. Tannehill, Ivan Ray. The Hurricane Hunters. Dodd, 1956. The story of great storms of the past, of the adventurous men who tried to do something about them, and the ways in which modern science and aviation are being used to improve our knowledge and to minimize storm damages. Vaeth, J. Gordon. 200 Miles Up: The Conquest of the Upper Air. Ronald, 1955. A book about rockets, balloons, and artificial satellites. Biochemistry Borek, Ernest. Man, the Chemical Machine. Columbia Univ. Press, 1952. A connected story showing the biochemist at his bench, tracing the growth of the ideas that guide his hands and unfolding his view on the mechanics of the living machine. Carlson, Anton J., and Victor Johnson. The Machinery of the Body. See entry under Anatomy, p. 278. Biography Campbell, Murray and Harrison Hatton. Herbert H. Dow: Pioneer in Creative Chemistry. Appleton, 1951. "This book is an account, in non-technical terms, of one man's share in the founding of a company and, in a way, of an industry" (the manufacture of chemicals). Clapesattle, Helen. The Doctors Mayo (2d ed.) . Univ. of Minne- sota Press, 1954. The story of a father and two sons of worldwide fame and their clinic, where men come from all over the world for treatment and instruction in the healing arts. Curie, Eve. Madam Curie. Doubleday, 1953. The life story of Marie Curie, discoverer of radium, as told by her daughter, reveals the reward that comes through personal sacrifice and persistence in scientific research. 282 de Kruif, Paul. Men Against Death. Harcourt, 1932. The author, with his unusual gift for making the past come alive, tells us of important persons and events in the advance of medicine and the control of disease. Dubos, Rene J. Louis Pasteur: Free Lance of Science. Little, 1950. The story of a man whose labors enriched many fields of science. Farber, Eduard. Nobel Prize Winners in Chemistry. Henry Schuman, 1953. Fifty-one chemists have received the Nobel Prize between 1901 and 1950. For each this book presents a brief biographical sketch, a descrip- tion of his prize-winning work, and a statement of the theoretical significance and the practical results of that work. Fermi, Laura. Atoms in the Family: My Life with Enrico Fer- mi. See entry under Atomic Science, p. 280. Fox, Ruth. Great Men of Medicine. Random House, 1947. Brief sketches of the lives and work of nine men: Vesalius, Pare, Har- vey, Jenner, Laennec, Semmelweis, Morton, Lister, and Koch. Gollomb, Joseph. Albert Schweitzer: Genius in the Jungle. Van- guard, 1949. The story of the man who sacrificed his career as a concert organist, preacher, and teacher to study medicine, that he might devote himself to a life of service as physician, friend, and teacher of the native popu- lations of West Africa. The success of his work among these people has brought him world renown. Heathcote, Niels H. deV. Nobel Prize Winners ni Physics. Hen- ry Schuman, 1953. Outstanding developments in physics are told through the accomplish- ments of 54 scientists who won the Novel Prize in physics. Kendall, James. Great Discoveries by Young Chemists. Crow- ell, 1953. Stories of the lives of young chemists. Kugelmass, J. Alvin. /. Robert Oppenheimer and the Atomic Story. See entry under Atomic Science, p. 280. Lavine, Sigmund A. Steinmetz: Maker of Lighting. Dodd, 1955. "This is the story of Charles Proteus Steinmetz, a genius in mathe- matics, a talented chemist and a wizard in electricity." Levinger, Elma Ehrlich. Albert Einstein. Messner, 1949. This biography shows that a scientist such as Einstein is not only a machine creating science but also a human being with feelings and desires. Seton, Ernest Thompson. Trail of an Artist Naturalist. Scrib- ner, 1948. The life story of one of America's most famous naturalists. Silverman, Milton. Magic in a Bottle. Macmillan, 1953. The story of the men behind the chief drugs in modern medicine. Sloop, Mary T. Martin. Miracle in the Hills. McGraw, 1953. A woman physician devotes 40 years of her life to practice in the mountains of North Carolina where she and her husband dedicated themselves to the health and education of the people. 283 Sootin, Harry. Isaac Newton. Messner, 1955. The story of the amazing career of the eminent scientist and professor. Sootin, Harry. Michael Faraday: From Errand Boy to Master Physicist. Messner, 1954. The story of an errand boy and apprentice bookbinder who educated himself in science, conducted experiments in electricity in his room, and became an apprentice in Sir Humphrey Davy's laboratory. In later life Davy said his greatest contribution to science was Michael Faraday. Stevenson, Lloyd G. Nobel Prize Winners in Medicine and Physiology. Henry Schuman, 1953. Stories of sixty winners of the Nobel Prize — brief biography, descrip- tion of prize-winning work, and the consequences in theory and practice ■ — give an insight into medical and physiological progress. Teale, Edwin Way (ed.). The Insect World of J. Henri Fabre. Dodd, 1950. Excerpts from the writings of a famous entomologist. Thompson, Elizabeth. Harvey Cushing : Surgeon, Author, Art- ist. Henry Schuman, 1950. The career of the man whose work in neurological surgery and its prob- lems made operations on the brain of little more hazard than those of the abdomen. Untermeyer, Louis. Makers of the Modem World. Simon & Schuster, 1955. A series of critical and biographical studies of 92 men and women whose contributions to literature, the humanities, the arts, the sciences, and politics have determined the course and pattern of our present-day world. Written especially for lay readers. Weiner, Norbert. / Am a Mathematician. Doubleday, 1956. The autobiography of a famous member of the Massachusetts Institute of Technology's faculty. Through the story of his life we discern some of the recent happenings in the development of mathematical science in relation to the problems posed by this technological age. Williams, Beryl, and Samuel Epstein. William Crawford Gorgas: Tropic Fever Fighter. Messner, 1953. The story of Gorgas, who fought yellow fever in Panama, Havana, and South America. To Gorgas, more than to the brilliant engineers, be- longs credit for the successful completion of the Panama Canal. Woodham-Smith, Cecil. Lonely Crusader: The Life of Florence Nightingale. McGraw (Whittlesey House), 1951. The story of the young lady who deserted English society life to enter the then "lowly and inferior" profession of nursing, and raised it to high standards. Young, Agatha. Scalpel: Men Who Made Surgery. Random House, 1956. The book tells of the men who solved the four great problems of surg- ery: the control of bleeding, the control of pain, the control of infection, and the control of shock. 284 Biology Bates, Marston. The Prevalence of People. See entry under An- thropology, p. 279. Berrill, N. J. Sex and the Nature of Things. Dodd, 1953. This book will tell you much about the creatures of the world, and about your own heritage extending back into prehistory. Bonner, John Tyler. Cells and Societies. Princeton Univ. Press, 1955. Sameness and diversity in living societies are ably discussed through such examples as man, apes, Alaskan fur seals, red deer, ants, colonial invertebrates, and plants. Carson, Rachel L. The Edge of the Sea. Houghton, 1955. The Atlantic coast of the United States has been chosen for pictures and descriptions of shore life and the forces of nature which open up a whole new world of life, beauty, and wonder. Carson, Rachel. The Sea Around Us. Oxford, 1951. One of the finest examples of popular scientific writing of the present century. Miss Carson introduces the basic things with which the science of oceanography is concerned in both its physical and biological aspects. Dobzhansky, Theodosius. Evolution, Genetics, and Man. See entry under Anthropology, p. 279. Singer, Charles. A History of Biology. Henry Schuman, 1951. This book is concerned with the history of our knowledge of life and of living things, of which man is a single example. Smart, W. M. The Origin of the Earth. See entry under Astron- omy, p. 280. Smith, F. G. Walton, and Henry Chapin. The Sun, the Sea and Tomorrow. Scribner, 1954. Discusses possibilities for future utilization of the sun, as the principal source of energy and life, and the ocean, as a vast pastureland and reservoir of minerals for life. Storer, John H. The Web of Life: A First Book of Ecology. Devin-Adair, 1956. A study of the interrelationships of living things. Botany Coulter, Merle C. The Story of the Plant Kingdom. Univ. of Chicago Press, 1935. This general survey of botany provides a review of the plant science field with all of its various specialties, and follows the development of the plant kingdom from its simple origins to its diversification into a quarter million living species. Hylander, Clarence J. The World of Plant Life. Macmillan, 1956. A comprehensive survey of the plant world of America. Peattie, Donald Culross. Flowering Earth. Putnam, 1939. A discussion of plant life, past and present. Piatt, Rutherford. This Green World. Dodd, 1942. A book about the interesting facts associated with plants (including trees) which reveal how the natural world "works." 285 Zim, Herbert S. Plants. Harcourt, 1947. An amateur has surveyed the entire plant kingdom for the enlighten- ment of other amateurs. Chemistry Ball, Max W. This Fascinating Oil Business. Bobbs, 1940. An excellent layman's compendium of the entire history of petroleum: geological formation, discovery, production, refining, by-products, trans- portation, marketing and uses. Boucher, Paul E. Fundamentals of Photography. Van Nostrand, 1955. This book is designed to give practical amateurs a better understanding of photographic theory and principles and thus aid them in making better pictures. Procedures for various photographic operations and for processing film and prints are described. Campbell, Murray and Jarrison Hatton. Herbert H. Dow: Pio- neer in Creative Chemistry. See entry under Biography, p. 282. Curie, Eve. Madam Curie. See entry under Biography, p. 282. Dean, Gordon. Report on the Atom. See entry under Atomic Science, p. 280. Diamond, Freda. The Story of Glass. See entry under Archaeol- ogy, p. 279. Farber, Eduard. The Evolution of Chemistry. Ronald, 1952. The author recognizes three periods in the history of chemistry: its emergence as a science, the construction of chemical systems, and the age of specialization and industrialization. Farber, Eduard. Noble Prize Winners in Chemistry. See entry under Biography, p. 282. Friend, J. Newton. Man and the Chemical Elements. Scribner, 1953. Each section begins with the earliest theories, evidences of use, or facts concerning a group of chemical elements and brings the story up to modern times. Haynes, Williams. Cellulose, the Chemical that Grows. Double- day, 1953. The book describes old, new, and possible future uses of cellulose. Jaffe, Bernard. Crucibles: The Story of Chemistry. Simon and Schuster, 1951. Beginning with Bernard Trevisan (1406-1490) who tried unsuccessfully to manufacture gold, the story of the advance of chemistry is told through events in the lives of outstanding men including Paracelsus, Priestly, Cavendish, Lavoisier, and many others. Kendall, James. Great Discoveries by Young Chemists. See en- try under Biography, p. 282. Killeffer, D. H. Two Ears of Corn, Two Blades of Grass. Var Nostrand, 1955. The story of the development of modern machines and processes. Synthetic fabrics, synthetic rubber, new drugs, the manufacture of 286 vitamins, the preservation of wood, agriculture without soil, and many- other wonders are described. Smart, W. M. The Origin of the Earth. See entry under Astron- omy, p. 280. Conservation Allen, Durward L. Our Wildlife Legacy. Funk, 1954. A digest of wildlife science properly related to the conservation of other resources. Archer, Sellers G. Soil Conservation. See entry under Agricul- ture, p. 278. Gabrielson, Ira N. Wildlife Conservation. Macmillan, 1952. Develops three basic concepts: Soil, water, forest, and wildlife conser- vation are part of one inseparable program. Wildlife must have an environment suited to its needs. Any use of a living resource must be limited to not more than the annual increase if essential seed stock is to be continually available. Hochbaum, H. Albert. Travels and Traditions of Waterfowl. Univ. of Minnesota Press, 1955. The story of the travels of North American ducks, geese, and swans written from personal knowledge and observation. Kellogg, Charles E. The Soils that Support Us. See entry under Agriculture, p. 278. King, Thomson. Water: Miracle of Nature. Macmillan, 1955. A story of the nature of water, and water in relation to man. Sears, Paul B. Deserts on the March. See entry under Agricul- ture, p. 278. Dentistry Bremmer, M. D. K. The Story of Dentistry (3rd ed.). Dental Items of Interest Pub. Co., 1954. The history of dentistry partly parallels the history of medicine, but in many ways has its own peculiar history. Electronics Eaton, J. R. Beginning Electricity. Macmillan, 1952. "This book on electricity is written for anyone with enough curiosity to work a cross word puzzle and with enough mathematical knowledge to buy groceries without being shortchanged." Pierce, John R. Electrons, Waves and Messages. Hanover House, 1956. "This book is about electronics in the sense of radio, of television, of sending messages across the continent, or of detecting planes by radar. Its aim is to give some idea of electronic devices and systems and how they woi'k." Skilling, Hugh Hildreth. Exploring Electricity: Man's Unfin- ished Quest. Ronald, 1948. A colorful tale of first-hand experiences of the ancestors of modern electrical discovery, invention, and utilization. 287 Upton, Monroe. Electronics for Everyone: The Story of Elec- tricity in Action. Devin-Adair, 1955. "Progress in electricity is joined to the lives and struggles of the scientists and inventors who have given us such things as the condenser, the electric battery and generator, FM radar, the proximity, fuse, and transistor." Engineering Ball, Max W. This Fascinating Oil Business. See entry under Chemistry, p. 286. Campbell, Murray and Harrison Hatton. Herbert H. Dow: Pio- neer in Creative Chemistry. See entry under Biography, p. 282. Dean, Gordon. Report of the Atom. See entry under Atomic Science, p. 280. Diebold, John. Automation : The Advent of the Automatic Fac- tory. Van Nostrand, 1952. A book about automatic devices and automatic factories that have revolutionized the manufacturing and industrial worlds, have con- tributed to the advancement of workers and their wages, and have given rise to new human problems we must solve. Eaton, J. R. Beginning Electricity. See entry under Electron- ics, p. 287. Grinter, L. E., et al. Engineering Preview. Macmillan, 1947. The fundamentals of engineering science, for readers with some back- ground in mathematics and elementary science. Each branch of the engineering profession is described. Haynes, Williams. Cellulose, the Chemical That Grows. See entry under Chemistry, p. 286. Killeffer, D. R. Two Ears of Corn, Two Blades of Grass. See entry under Chemistry, p. 286. King, Thompson. Water: Miracle of Nature. See entry under Conservation, p. 287. Kugelmass, J. Alvin. /. Robert Oppenheimer and the Atomic Story. See entry under Atomic Science, p. 280. Ley, Willy. Engineers' Dreams. Viking, 1955. History discloses that many so-called wild dreams of inventive persons became realities. This book outlines projects that appear feasible for the future. Meyer, Jerome S. World Book of Great Inventions. World Pub. Co., 1956. The story of great inventions is the story of . man's amazing vision, tenacity, and determination to overcome all obstacles in order to im- prove his world. Smith, H. Shirley. The World's Great Bridges. Harper, 1953. Details of the problems that confronted builders of certain bridges are described with the aid of drawings and photographs. Storck, John, and Walter D. Teague. Flour for Man's Bread: A History of Milling. See entry under Agriculture, p. 278. 288 Exploration Andrews, Roy Chapman. Beyond Adventure: The Lives of Three Explorers. Duell, 1954. The author says: "This book tells the life stories of three men, Robert E. Peary, Carl Akeley, and myself. We were all explorers: Peary in geography, Akeley in natural history, and I in science." Andrews, Roy Chapman. This Amazing Planet. Putnam, 1940. A collection of eighty fascinating true stories of animals the author has met on his expeditions throughout the world and at home. Cousteau, J. Y. The Silent World. See entry under Archaeology. Durrell, Gerald M. The Overloaded Ark. Viking, 1953. A unique chronicle of a 6-month's collecting trip by two young natural- ists in the rain forests of the Cameroons in West Africa, one of the few places on the African Continent that remains in its primitive condition. Hermann, Paul. Conquest by Man. Harper, 1954. This is the story of man's achievements in explaining, occupying, and developing the world, tracing the steps by which the world has achieved its state of advanced technology. Heyerdahl, Thor. Kon-Tiki: Across the Pacific by Raft. Rand McNally, 1950. Heyerdahl made a dangerous and dramatic voyage from the coast of Peru to the Island of Tahiti on a 40-foot balsa-wood raft, to test a theory that the inhabitants of the South Sea Islands came originally from Peru. Mohr, Charles E. and Horace N. Sloane (ed.). Celebrated Amer- ican Caves. Rutgers Univ. Press, 1955. Describes caves important in the field of exploration, science, history, or legend. Rodahl, Kaare. North: The Nature and Drama of the Polar World. See entry under Aviation, p. 281. Sanderson, Ivan T. Follow the Whale. Little, 1956. An absorbing history from ancient times to the present of the pursuit, capture, and utilization of whales. Spectorsky, A. C. (ed.). The Book of the Mountains. Appleton, 1955. A magnificent collection of writings, comprehensive and well-balanced, portraying man's conflicts, reactions, adaptations, discoveries, ideas, and life on the mountains. The photographs are even more outstanding than the writings. Spectorsky, A. C. (ed.). The Book of the Sea. Appleton, 1954. This anthology of writings about the sea, superbly illustrated, is a joyful adventure. History, geography, biography, fiction, and science all are represented. Forestry Baker, Richard St. Barbe. Green Glory: The Forests of the World. Wyn, 1949. A narrative guide to the great forests of the world, a story of the place of trees in relation to other living things, and an account of the science of forestry. 289 Carhart, Arthur H. Timber in Your Life. Lippincott, 1955. This story of wood to burn, fire, blazing new trails, rangers, big green farms, and tomorrow's timber tells the history and the future of our forests. Geography Hermann, Paul. Conquest by Man. See entry under Exploration, p. 289. Sanderson, Ivan T. Follow the Whale. See entry under Explora- tion, p. 289. Spectorsky, A. C. (ed.). The Book of the Mountains. See entry under Exploration, p. 289. Geology Croneis, Cary, and William C. Krumbein. Dow?i to Earth: An Introduction to Geology. Univ. of Chicago Press, 1936. An account of the origins and formation of such phenomena as soil, mountains, and gems. Fenton, Caroll Lane, and Mildred Adams Fenton. The Rock Book. Doubleday, 1940. In this book you will learn many surprising facts about rocks and the science of mineralogy. Fenton, Carroll L. and Mildred A. Giants of Geology. Double- day, 1952. After tracing the beginnings of our knowledge of the earth, this book gives an account of outstanding American and Canadian geologists. Kuenen, P. H. Realms of Water. Wiley, 1955. Three sciences and a myriad of subsciences are included in this study of water in the oceans, in the atmosphere, underground, and on the surface. Mohr, Charles E. and Horace N. Sloane (eds.). Celebrated American Caves. See entry under Exploration, p. 289. Smart, W. M. The Origin of the Earth. See entry under As- tronomy, p. 278. History of Science Bell, Eric Temple. Men of Mathematics. Simon & Schuster, 1937. "A series of stories about certain mathematicians whom we hold most responsible for the present-day scope and magnitude of mathematics." Bremmer, M. D. K. The Story of Dentistry (3rd ed.). See en- try under Dentistry, p. 287. Cohen, I. Bernard. Science, Servant of Man. Little, 1948. This book deals with one of the most important problems of our age: the relation of scientific discovery to our daily lives, our well-being, and national security. Farber, Edward. The Evolution of Chemistry. See entry under Chemistry, p. 286. 290 Friend, J. Newton. Man and the Chemical Elements. See entry under Chemistry, p. 286. Jaffe, Bernard. Men of Science in America. Simon and Schus- ter, 1946. The role of science in the growth of the United States is portrayed through accounts of the lives of 20 leaders, beginning with Thomas Harriott (1560-1621) and ending with Ernest Orlando Lawrence, who is still active in the field of atomic science. Moore, Patrick. The Story of Man and the Stars. See entry un- der Astronomy, p. 280. Moulton, Forest Ray, and Justus J. Schifferes. The Autobiog- raphy of Science. Doubleday, 1953. A collection of key passages from master writings of all sciences from the beginning of history. Rapport, Samuel, and Helen Wright (eds.). Great Adventures in Medicine. Dial Press, 1952. An anthology of original writings of outstanding workers in the field of medicine. These writers present realistic accounts of their experiences and of the opportunities for helping mankind through the healing arts. Singer, Charles. A History of Biology. See entry under Biology. Storck, John, and Walter D. Teague. Flour for Man's Bread: A History of Milling. See entry under Agriculture, p. 278. Taylor, F. Sherwood. An Illustrated History of Science. Prae- ger, 1955. A synthesis of what has been transmitted by documents and what the author and artist know about the ways of life in days gone by, providing a visual idea of the men and events that brought science to its present position of pre-eminence. Taylor, F. Sherwood. A Short History of Science and Scien- tific Thought. Norton, 1949. In his historical account, the author has inserted excerpts from the original writings of key scientists throughout the centuries from the Babylonians to Einstein. Untermeyer, Louis. Makers of the Modern World. See entry under Biography, p. 282. Mathematics Bakst, Aaron. Mathematics: Its Magic and Mastery (2d. ed.). Van Nostrand, 1952. Shows the versatility and importance of mathematics in many fields of human activity. Bell, Eric Temple. Men of Mathematics. See entry under His- tory of Science, p. 290. Berkeley, Edmund Callis. Giant Brains or Machines That Think. Wiley, 1949. The increasing use of electronic calculators in research, business, and industry has created a great interest in their construction and opera- tion. This book is so designed that it can be read by anyone. 291 Coleman, James A. Relativity for the Layman. William Fred- erick Press, 1954. The story behind the theory of relativity is better than good fiction. You will be surprised to find how many scientists had a "finger in the pie" and will be fascinated by the author's amusing diagrams. Courant, Richard, and Herbert Robbins. What Is Mathematics? Oxford, 1941. The purpose of this book is to look beyond the abstract formalism of mathematics and to discover what mathematics is really concerned with. It requires some high school mathematics plus the ability to do some thinking on one's own initiative. Dantzig, Tobias. Number: The Language of Science. Macmillan, 1954. It is the aim of this book to restore the cultural content of mathematics and to present the evolution of number as a profoundly human story. Friend, J. Newton. Numbers: Fun and Facts. Scribner, 1954. Account of numbers, their origin, and the traditions, legends and superstitions that have collected around numbers. Gamow, George. One, Two, Three . . . Infinity. Viking, 1954. Here we learn of atoms, stars, genes, fourth dimensions, relativity and other important things, including the days of creation in this enter- taining survey of scientific knowledge. Hogben, Lancelot. Mathematics for the Million (3rd ed.). Nor- ton, 1951. The author has succeeded in proving his conviction that the study of mathematics can "be made exciting to ordinary people, as, for instance, myself." Kasner, Edward and James Newman. Mathematics and the Imagination. Simon & Schuster, 1940. A book, not too easy and not too "tough", to stimulate interest in the mother of all sciences. Contains an excellent annotated list of further readings in mathematics and related subjects. Levinger, Elma Ehrlich. Albert Einstein. See entry under Biog- raphy, p. 282. Lieber, Lillian R. The Education of T. C. Mits. Norton, 1944. The book is about mathematics, science, thinking, hunches, common sense, and many other things including preconceived notions. Lieber, Lillian R. Infinity. Rinehart, 1953. The book introduces you to mathematical methods and ideas you may have believed were too difficult to understand. Lieber, Lillian R. Einstein Theory of Relativity. Rinehart, 1945. Those who wish an introduction to the important field of relativity can find here what it is, what it does, and what it is good for. Logsdon, Mayme I. A Mathematician Explains. Univ. of Chi- cago Press, 1947. A supplementary book which will give the layman a general survey of the science that underlies all other sciences. Meyer, Jerome S. Fun with Mathematics. World Pub. Co., 1952. Since the earliest development of mathematics, certain mysteries, puzzles, and tricks have been created, preserved, and transmitted from generation to generation. They provide an enjoyable and painless method of learning more about mathematics. 292 Ogilvy, C. Stanley. Through the Mathescope. Oxford Univ. Press, 1956. "A mathescope is not a physical instrument. It is an intellectual instru- ment, with reason for its pedestal and inspiration for its lenses. No one has ever seen an integral, or a geometric point, or, for that matter, a number. You can see the symbol that someone writes down to stand for a number, but a number itself has no earthly physical being to see, touch, or smell. Mathematicians, as we shall see, deal not with tangibles but with ideas." Reid, Constance. From Zero to Infinity. Crowell, 1955. This book tells the history and other extraordinary things about each of the digits, 1 to 9, the zero, and infinity. Sootin, Harry. Isaac Newton. See entry under Biography, p. 282. Wiener, Norbert. / Am a Mathematician. See entry under Biog- raphy, p. 282. Medicine Asimov, I. The Chemicals of Life. Abelard-Schuman, 1954. An easy introduction to the chemical make-up of a body, describing the chemical reactions that are essential to life, and the role of enzymes, vitamins, and hormones in life and health. Burnet, Sir Macfarlane. Natural History of Infectious Disease. Cambridge Univ. Press, 1953. A discussion of the complex problems of infectious diseases, the causative organisms, and the relation of organism and infection to the total biological environment. Clapesattle, Helen. The Doctors Mayo. See entry under Biog- raphy, p. 282. Cooley, Donald G. The Science Book of Wonder Drugs. Watts, 1954. This is the story of the sulfa drugs, the antibiotics, hormones, vitamins, and other chemically or biologically produced methods of treating diseases. de Kruif , Paul. Men Against Death. See entry under Biography, p. 282. Dubos, Rene J. Louis Pasteur: Free Lance of Science. See en- try under Biography, p. 282. Dubos, Rene, and Jean Dubos. The White Plague: Tuberculo- sis, Man and Society. Little, 1952. The book reveals that tuberculosis is a social disease, presenting prob- lems other than medical ones. Faxon, Nathaniel W. (ed.). The Hospital in Contemporary Life. Harvard Univ. Press, 1949. Eight eminent doctors discuss the history of hospitals, their organiza- tion and needs, and their future possibilities in caring for the sick and in serving as research centers. Fox, Ruth. Great Men of Medicine. See entry under Biography, p. 282. 293 Glynn, John H. The Story of Blood. Wyn, 1948. A story of the growth of our knowledge of blood, its functions, and its responsibility in maintaining life. Gollomb, Joseph. Albert Schiveitzer: Genius in the Jungle. See entry under Biography, p. 282. Haggard, Howard W. Devils, Drugs, and Doctors. Harper, 1929. The progress of civilization is measured in this story of the displace- ment of ignorance, myth and superstition in the care of human beings at the time of birth, and during illness and disease. Rapport, Samuel, and Helen Wright (eds.). Great Adventures in Medicine. See entry under History of Science, p. 290. Roueche, Berton. Eleven Blue Men, and Other Narratives of Medical Detection. Little, 1954. The book contains twelve first-rate "detective" stories which show how medical science works. Sloop, Mary T. Martin. Miracle in the Hills. See entry under Biography, p. 282. Spencer, Steven M. Wonder of Modern Medicine. McGraw, 1953. The author interviewed physicians, research workers, hospital admin- istrators, nurses, and patients to secure the information for his story of great advances in the treatment of disease. Stevenson, Lloyd G. Nobel Prize Winners in Medicine and Physiology. See entry under Biography, p. 282. Thompson, Elizabeth. Harvey Gushing: Surgeon, Author, Art- ist. See entry under Biography, p. 282. Williams, Beryl, and Samuel Epstein. William Crawford Gor- gas: Tropic Fever Fighter. See entry under Biography, p. 282. Woodham-Smith, Cecil. Lonely Crusader: The Life of Florence Nightingale. See entry under Biography, p. 282. Young, Agatha. Scalpel: Men Who Made Surgery. See entry under Biography, p. 282. Zinsser, Hans. Rats, Lice and History: A Study in Biography. Little, 1935. A biography of a disease and its influence on the history of man. Metallurgy Rogers, Bruce A. The Nature of Metals. Iowa State Col. Press, 1951. If metals were animate, then we would call this book "the anatomy and physiology of metals." Sullivan, John W. W. The Story of Metals. Iowa State Coll. Press, 1951. This book traces the story of metals and metallurgy, past and present, and gives a forecast of the future. 294 Meteorology Laird, Charles and Ruth Laird. Weather casting. Prentice-Hall, 1955. As outlined in this book, you can build your own weather station; and from your own backyard you can take systematic observations, watch the pageant of the skies, study the principles of atmospheric behavior, and make your own forecasts. Longstreth, T. Morris. Understanding the Weather. Macmillan, 1953. Weather forecasting is the attempt to predict definite effects from rather nebulous causes. This handbook gives a bird's-eye view of the course, with its roughs and its traps. Kuenen, P. H. Realms of Water. See entry under Geology, p. 290. Murchie. Guy. Jr. Song of the Sky. See entry under Aviation, p. 281. Tannehill, Ivan Ray. The Hurricane Hunters. See entry under Aviation, p. 281. Vaeth, J. Gordon. 200 Miles Up: The Conquest of the Upper Air. See entry under Aviation, p. 281. Microbiology Burnet, Sir Macfarlane. Natural History of Infectious Disease. See entry under Medicine, p. 293. de Kruif , Paul. Men Against Death. See entry under Biography, p. 282. de Kruif. Paul. Microbe Hunters. Harcourt, 1932. This is the story of the new world of science made possible by the invention of the microscope and by the great advances that resulted. Dubois, Rene J. Louis Pasteur: Free Lance of Science. See entry under Biography, p. 282. Dubos, Rene, and Jean Dubos. The White Plague: Tuberculo- sis, Man and Society. See entry under Medicine, p. 293. Fox, Ruth. Milestones of Medicine. Random House, 1950. Milestones selected by the author include: two gifts from the physi- cists; the growth of the drug industry to a profession of scientific service; the work of scientists in the war on diphtheria and yellow fever; and the work of those twentieth-century miracles, insulin and penicillin. Grant, Madeline Parker. Microbiology and Human Progress. Rinehart, 1953. Written to acquaint students with the general principles and accom- plishments of microbiology and bacteriology. Cultural aspects of the biological studies are presented to emphasize the interdependence of science and society. Haggard, Howard W. Devils, Drugs, and Doctors. See entry under Medicine, p. 293. 295 Roueche, Berton. Eleven Blue Men, and Other Narratives of Medical Detection. See entry under Medicine, p. 293. Williams, Beryl, and Samuel Epstein. William Crawford Gor- gas: Tropic Fever Fighter. See entry under Biography, p. 284. Zinsser, Hans. Rats, Lice and History: A Study in Biography. See entry under Medicine, p. 293. Mineralogy Fenton, Carroll Lane, and Mildred Adams Fenton. The Rock Book. See entry under Geology, p. 290. Kraus, E. H., and C. B. Slawson. Gems and Gem Materials. McGraw, 1947. This book discusses chemical and physical properties of gems, their formation and occurance in nature, and the cutting and polishing of gems. Reinfeld, Fred. Uranium and Other Miracle Metals. Sterling, 1955. Here you learn about the Atomic Energy Commission, finding and mining uranium, making atomic fuel, radioisotopes, nuclear fission and reactors, atomic power, and miracle metals of various kinds. Oceanography Beebe, William. Half Mile Down. Duell, 1951. Dr. Beebe describes his descent to a depth of over 3,000 feet in the waters off Bermuda in his ingenious bathysphere. Carson, Rachel L. The Edge of the Sea. See entry under Biol- ogy, p. 285. Carson, Rachel. The Sea around Us. See entry under Biology, p. 285. Cousteau, J. Y. The Silent World. See entry under Archaelogy, p. 279. Douglas, John Scott. The Story of the Oceans. Dodd, 1952. This narrative introduction to the science of the sea partakes of all the basic sciences as they relate to the waters of the earth. Kuenen, P. H. Realms of Water. See entry under Geology, p. 290. Russell, F. S. and C. M. Yonge. The Seas: Our Knowledge of Life in the Sea and How It Is Gained. Warne & Co., 1936. An introduction to the entire science of oceanography which partakes of physics, chemistry, geology, astronomy, meteorology, geography, and many branches of biology. The section on fishery research shows what science is doing to further our knowledge and enable us to conserve marine resources. Smith, F. G. Walton, and Henry Chapan. The Sun, the Sea and Tomorrow. See entry under Biology, p. 285. Spectorsky, A. C. (ed.). The Book of the Sea. See entry under Exploration, p. 289. 296 Paleontology Fenton, Carroll Lane. Life Long Ago: The Story of Fossils. Day, 1937. Life during those millions of years before recorded history has left its own history in the rock strata of the earth. Simpson, George G. Life of the Past: An Introduction to Pale- ontology. Yale Univ. Press, 1953. Here is an opportunity for a walk through all time during which you may see the forms of life that inhabited the lands and waters many thousands of years before human history began. Pharmacy Cooley, Donald G. The Science Book of Wonder Drugs. See entry under Medicine, p. 293. Fox, Ruth. Milestones of Medicine. See entry under Microbiol- ogy, p. 295. Haggard, Howard W. Devils, Drugs, and Doctors. See entry under Medicine, p. 293. Silverman, Milton. Magic in a Bottle. See entry under Biog- raphy, p. 282. Physics Asimov, Isaac. Inside the Atom. See entry under Atomic Sci- ence, p. 280. Berkeley, Edmund Callis. Giant Brains or Machines That Think. See entry under Mathematics, p. 291. Boucher, Paul E. Fundamentals of Photography. See entry un- der Chemistry, p. 286. Coleman, James A. Relativity for the Layman. See entry un- der Mathematics, p. 291. Dean, Gordon. Report on the Atom. See entry under Atomic Science, p. 280. Diamond, Freda. The Story of Glass. See entry under Archaeol- ogy, p. 279. Fermi, Laura. Atoms in the Family : My Life with Enrico Fer- mi. See entry under Atomic Science, p. 280. Fox, Ruth. Milestones of Medicine. See entry under Microbiol- ogy, p. 295. Gamow, George. Mr. Tompkins Explores the Atom. See entry under Atomic Science, p. 280. 297 Gamow, George. Mr. Tompkins in Wonderland. Cambridge Univ. Press, 1953. An analogy of a billiard game explains the quantum theory, speed limits on city streets explain relativity, a wild-animal hunt explains the wave character of matter. By this unique book we are taught princi- ples of modern physics that are baffling to all except a few very learned people. Glasstone, Samuel. Sourcebook on Atomic Energy. See entry under Atomic Science, p. 280. Heathcote, Niels H. de V. Nobel Prize Winners in Physics. See entry under Biography, p. 282. Hecht, Selig. Explaining the Atom. See entry under Atomic Science, p. 280. King, Thomason. Water: Miracle of Nature. See entry under Conservation, p. 287. Kugelmass, J. Alvin. /. Robert Oppenheimer and the Atomic Story. See entry under Atomic Science, p. 280. Lavine, Sigmund A. Steinmetz: Maker of Lighting. See entry under Biography, p. 282. Lieber, Lillian R. Einstein Theory of Relativity. See entry un- der Mathematics, p. 291. Meyer, Jerome S. World Book of Great Inventions. See entry under Engineering, p. 288. Murchie, Guy, Jr. Song of the Sky. See entry under Aviation, p. 281. Pfeiffer, John. The Changing Universe. See entry under As- tronomy, p. 280. Pierce, John R. Electrons, Waves and Messages. See entry un- der Electronics, p. 287. Reinfeld, Fred. Uranium and Other Miracle Metals. Sterling, 1955. See entry under Mineralogy, p. 296. Semat, Henry. Physics in the Modern World. Rinehart, 1947. Traces the development of the major physical concepts and the im- portant physical laws. Skilling, Hugh Hildreth. Exploring Electricity: Man's Unfin- ished Quest. See entry under Electronics, p. 287. Smart, W. M. The Origin of the Earth. See entry under As- tronomy, p. 280. Sootin, Harry. Isaac Neivton. See entry under Biography, p. 282. Sootin, Harry. Michael Faraday: From Errand Boy to Master Physicist. See entry under Biography, p. 282. Upton, Monroe. Electronics for Everyone: The Story of Elec- tricity in Action. See entry under Electronics, p. 287. 298 Woodbury, David O. The Glass Giant of Palomar. See entry under Astronomy, p. 280. Physiology Asimov, I. The Chemicals of Life. See entry under Medicine, p. 293. Carlson, Anton J., and Victor Johnson. The Machinery of the Body. See entry under Biochemistry, p. 282. Glynn, John H. The Story of Blood. See entry under Medicine, p. 293. Singer, Charles. A History of Biology. See entry under Biol- ogy, p. 285. Sproul, Edith E. The Science Book of the Human Body. See entry under Anatomy, p. 278. Stevenson, Lloyd G. Nobel Prize Winners in Medicine and Physiology. See entry under Biography, p. 282. Psychology Garrett. Henry E. Great Experiments in Psychology. Appleton, 1951. The novel approach of this book, through the biographical and histori- cal method, makes for an understandable introduction to the study of psychology. By considering great experiments, one gains a perspective of the study of "human-behavior-and-conduct science." Grabbe, Paul. We Call It Human Nature. Harper, 1939. A book which makes psychology intelligible in non-technical terms, using carefully chosen photographs and skillful diagrams. Munn, Norman L. The Evolution and Growth of Human Be- havior. Houghton, 1955. An explanation of the relationship between environment, inheritance, and human associations in developing a person's mind, his habits, his ability to work well with other people, and his other important per- sonal qualities. Roe, Annie. The Making of a Scientist. Dodd, 1953. A dual-purpose book which shows how a research study in psychology is conducted, and gives the facts about the lives of 64 scientists that led them into scientific careers. Science in General Baitsell, George A. (ed.). Science in Progress (1st ser.). Yale Univ. Press, 1939. Articles on cosmic rays, experimental alteration of heredity, the ex- panding universe, and aeronautics. Baitsell, George A. (ed.). Science in Progress (2nd ser.). Yale Univ. Press, 1940. Articles on cosmic rays, experimental alteration of heredity, the ex- panding universe, and aeronautics. 299 Baitsell, George A. (ed.). Science in Progress (3rd ser.). Yale Univ. Press, 1942. Articles on galaxies, the expanding universe, imagine formation by electrons, and synthetic rubber. Baitsell, George A. (ed.). Science in Progress (4th ser.). Yale Univ. Press, 1945. Eleven reports by famous scientists in fields which include nerve cells, energy and vision, streams of atoms, vacuum chemistry, and blood and blood derivatives. Baitsell, George A. (ed.). Science in Progress (5th ser.). Yale Univ. Press, 1947. Articles on the interior of the earth, genes and the chemistry of the organism, and the cancer problem. Baitsell, George A. (ed.). Science in Progress (6th ser.). Yale Univ. Press, 1949. Articles on eight synthetic elements, genes and evolution, nuclear fission, tuberculosis, and virus research. Baitsell, George A. (ed.). Science in Progress (7th ser.). Yale Univ. Press, 1951. Twelve reports by famous scientists on topics which include atomic and solar energy, the atomic structure and energy, radiation damage to human inheritance, genes and chromosomes, the first heart beat, and the beginning of emoryonic circulation. Baitsell, George A. (ed.). Science in Progress (8th ser.). Yale Univ. Press, 1953. Ten reports by famous scientists in fields which include the origin and evolution of the universe, the sun's atmosphere, the origin of man, luminescent organisms, and microwave spectroscopy, among others. Bronowski, J. The Common Sense of Science. Harvard Univ. Press, 1955. This book has long been needed to explain the relationship of science to art and literature. Douglas, John Scott. The Study of the Oceans. See entry under Oceanography, p. 296. Gamow, George. One, Two, Three . . . Infinity. See entry under Mathematics, p. 291. Kaempffert, Waldemar. Explorations in Science. Viking, 1953. An anthology of science articles that have appeared in popular maga- zines, revised and brought up-to-date. MacCurdy, Edward (ed.) . The Notebooks of Leonardo da Vinci. George Braziller, 1955. Here you may read from the actual writings of one of the most talented, profound, and diversified human beings of all time. Known primarily for his great works of art, he was also philosopher and scientist. Meyer, Jerome S. World Book of Great Inventions. See entry under Engineering, p. 288. Newman, James R. What Is Science? Simon & Schuster, 1955. In answering the question put by the title, the book presents twelve articles by eminent authorities to explain what each division of science embraces. 300 Scientific American Reader. Simon & Schuster, 1953. These collected articles by prominent scientists deal with the general topics of evolution in space, structure of the earth, structure of matter, atomic energy, origin of life, inheritance, origin of man, animal be- havior, psychology, and physiology. Shapley, et al. A Treasury of Science (3d eel.). Harper, 1954. A general survey of science, organized in sections: Science and the Scientist, the Physical World, the World of Life, The World of Man, Science and the Future. Spectorsky, A. C. (ed.). The Book of the Mountains. See entry under Exploration, p. 289. Spectorsky, A. C. (ed.). The Book of the Sea. See entry under Exploration, p. 289. Swezey, Kenneth M. Science Magic. McGraw, 1952. This little book describes many scientific experiments you can parform with the most ordinary things, and tells the scientific principles they illustrate. Untermeyer, Louis. Makers of the Modern World. See entry under Biography, p. 282. Verne, Jules. Twenty Thousand Leagues Under the Sea. World Pub. Co., 1946. The submarine and the wondrous underseas adventures of Captain Nemo, considered impossible when this book was published in 1870, have become common-place reality. Yost, Edna. American Women of Science. Lippincott, 1955. A book devoted exclusively to women who have made outstanding scien- tific contributions. Zoology Allen, Durward L. Our Wildlife Legacy. See entry under Con- servation, p. 287. Buchsbaum, Ralph M. Animals Without Backbones. Univ. of Chicago Press, 1948. Each group of invertebrates serves as an illustration of some important biological principle. Includes excellent photographs. Durrell, Gerald M. The Overloaded Ark. See entry under Ex- ploration, p. 289. Gray, James. How Animals Move. Cambridge Univ. Press, 1953. This book is designed to illustrate the biological and mechanical prin- ciples of animal movement. Hamilton, William J., Jr. American Mammals: Their Lives, Habits and Economic Relations. McGraw, 1939. The value of this book is its coverage of mammalogy in general for the entire United States. Chapters deal with ancestry, classification, nat- ural history, feeding habits, migration and distribution. Hegner, Robert. Parade of the Animal Kingdom. Macmillan, 1955. Describes the appearance and habits of a great number of animals, with many excellent photographs. 301 Hochbaum, H. Albert. Travels and Traditions of Waterfowl. See entry under Conservation, p. 287. Kinkead, Eugene. Spider, Egg, and Microcosm. Knopf, 1955. An account which considers these "miraculous designs" and the lives of three scientists who have dedicated themselves to their study. Lorenz, Konrad Z. King Solomon's Ring: New Light on Ani- mal Ways. Crowell, 1952. An outstanding naturalist provides new facts and penetrating observa- tions concerning animal mind and behavior. Norman, John R. A History of Fishes. Wyn, 1948. A comprehensive survey of the fields of ichthyology and fishery biology. Pope, Clifford H. The Reptile World: A Natural History of the Snakes, Lizards, Turtles, and Crocodilians. Knopf, 1955. An illustrated descriptive study of the principal members of the great class of vertebrates known as reptiles. Characteristics, geographical distribution, and habits are described for each of the species repre- sented. Sanderson, Ivan T. Folloiv the Whale. See entry under Explor- ation, p. 289. Seton, Ernest Thompson. Trail of an Artist Naturalist. See en- try under Biography, p. 282. Singer, Charles. A History of Biology. See entry under Biol- ogy, p. 285. Teale, Edwin Way. Grassroot Jungles: A Book on Insects. Dodd, 1950. Introduces the reader to the fascinating insect world around him. Teale, Edwin Way (ed.). The Insect World of J. Henri Fabre. See entry under Biography, p. 282. von Grisch, Karl. The Dancing Bees. Harcourt, 1955. The world's foremost authority on the honey bee tells its life story, and leads us through the interesting scientific researches by which its natural history and sociology have been learned. Wallace, George J. An Introduction to Ornithology. Macmillan, 1955. An introduction to ornithology as a field of scientific research, written with a minimum of professional-technical language. Zinsser, Hans. Rats, Lice and History: A Study in Biography. See entry under Medicine, p. 293. 302