William F. Kieffer College of Wooster Wooster, Ohio 44691
Chemistry, Curiosity, and Culture
I
believe that it was Glenn Seaborg who once said, "Just as middle ages man could not ignore the church, nor Rennaissance man the arts, nor eighteenth century man political thought, so modern man cannot ignore science." We probably all consider this to be so axiomatic that it need not be argued here. The purpose of this symposium seems to proclaim that science cannot ignore modern man. We must recognize that the majority of the twentieth and twenty-first century citizens who now crowd our campuses are not intending careers in science. If these future lawyers, clergymen, businessmen, mothers, musicians-all those %on-science majors3'-are to have any understanding or a t least appreciation of the part science plays in modern culture, we have to do the educating. I doubt that I need to devote time to a rationale for our obligations. Rather, I should like to describe an experiment in discharging that obligation. I apologize for the somewhat rambling and probably excessive first-person-singular nature of this discourse. However, I feel this approach is appropriate in that it gives first emphasis to an important point: this type of course probably is more personal than others. The effectiveness of a course for non-science majors is not measured by the amount or kind of scientific factual material tossed a t the student, but by the more subtle appreciation the students gain for how a scientist thinks about his science. This involves a variety of factors, not the least of which is the scientist's own enthusiasm. All too often, in our high sounding philosophical talk about the methods of scientific approach to problems, we forget the real pump-primer-the enthusiasm for a problem that is the first product of a scientist's curiosity. What this means for the course for non-science majors is that they ought to encounter a scientist revealing his enthusiasm. Their experience with scientific problem solving has to be vicarious. The thickness of this insulation from reality will be less if the professor is talking about his science. This makes the content and even the conduct of a successful course much more
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The 1968 ACS Award in Chemical Education, sponsored by the Laboratory Apptlratus and Optical Section of the Scientific Apparatus Makers Association, was presented to William F. Kieffer at the 155th Meeting of the ACS a t San Francisco in April of 1968. Dr. Kieffer, Professor of Chemistry at The Colis welllege of Wooster and for 12 yearseditor of THIS JOURNAL, known to our readers. From his pen have come many of the compelling ideas that have shaped chemical education during the past decade. From his editorial acumen has emerged a journal enriched in excellence and more deeply committed to the service of chemistry teachers around the world. From his example has risen a new dignity for L~O chemists ~~S those who teach. The staff of THIS J O U R N Awith everywhere in saluting Bill Kiefler for his accomplishments on behalf of chemkts and in recognizing him as the 1968 SAMA Award recipient..
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a matter of personal choice than does the typical teaching assignment in the chemistry curriculum. Therefore, my remarks about what I do are meant only as a description-by no means a prescription. This is why I have chosen my title. "Chemistry" implies that since I am a chemist, my enthusiasm will come through best if I discuss chemistry. "Curiosity" implies that I hope to set forth problems which are interesting to the thoughtful non-scientist, among those that I and other chemists have been curious about. "Culture" implies that the consequences of chemists' concern about these problems are significant far beyond mere intellectual gratification of chemists themselves. Perhaps I should first establish a frame of reference by describing the circumstances which have prompted my concern for the theme of this symposium. I have offered such a course on the campus of a liberal arts college for over 20 years. Enrollment is limited to upperclassmen; postponement until junior or senior year is encouraged. It is a one-semester, three-credit, nonlaboratory course which can count towards an area graduation requirement after the students have met the laboratory science requirement (usually in geology or biology). The advantage of having more mature students means that a broader base of relevance can be established. It also offers an opportunity for some synthesis of ideas and the pointing out of cultural relevancies that would be meaningless to freshmen taking a required survey-type course. The absence of laboratory work is admittedly more a matter of expediency than a desire for the optimum. These students, except possibly for the art and music majors, are more interested in thinking than doing. consequently, time is saved by using demonstration experiments rather than having the students struggle with techniques. Lectures are full of demonstrations and models, yet are kept informal; questions constantly fly in both directions, even though the professor is outnumbered 60 to 1. We have used a variety of reference texts accompanied by required or optional supplementary reading material. No text offered the desired flexibility of subject matter, yet most had the value of providing material on fundamentals for reference. In recent years, instead of a text, each student purchased the remarkably well-chosen collection of readings, "The Mystery of Matter," edited by Louise Young for the American Foundation for Continuing Education (1). This volume, which certainly is one that ultimately Address -an the occssion of the presentation of the Scientific Apparatus Meken Award in Chemical Education, 155th Meeting of the American Chemical Society, San Francisco, California, April, 1968. Delivered as pwt of the Symposium on Science Counes for Non-Science Majors on the program of the Division of Chemical Education.
should be part of a college graduate's permanent library, provides avariety of reading. There are original papers, for example, by Mendeleef and Curie, but also one finds Einstein's letter to President Roosevelt and a poem by Ogden Nash. Class time is spent more on exposition of background chemical information, but examinations invariably offer opportunity to examine philosophical or ethical implications. There are several points of view in my approach which may a t first seem paradoxical-or a t best a weak attempt to have the course be all things to all people. One is that I feel strongly that a chemistry course in a 1968 curriculum should include some very contemporary chemistry, yet should not ignore the grand sweep of historical development. My solution is never to devote a whole lecture to the history of chemistry but a t the same time try never to have a lecture which does not include some historical perspective. In similar fashion, I feel that lectures devoted exclusively to philosophical or ethical-religious values tend to be pompous or superficially unrelated. Here again, the attempt is made never to let any discussion conclude without some indication of how knowledge may demand wisdom in its application. I hope my remarks that follow may offerillustration. Chemistry
The first two topics discussed are broad ones: the development of our concept of the chemical element and the development of our concept of a chemical reaction, combustion. These have the advantage of starting with the familiar yet clearly showing how a concept grows from that to encompass the new and more sophisticated. "Elements from Aristotle to Seaborg" traces the idea of an element from the Greeks' quality through the alchemists' principles to Boyle's "perfectly unmingled bodies" (he was 150 years ahead of his time!) and Dalton's imaginative but provocative chemical calligraphy. This bedrock of theory offered the foundation for an overlay of empiricism that culminated in the periodic law. The screaming question of what must he the structure of atoms unrelated in mass but obviously similar in properties began to be answered a t the start of the present century. This theory in time was the layer on which a new empiricism has in recent years filled the vacancies and greatly extended the periodic table with man-made elements. Still the challenge emergeswhat new concepts by postulation (theories) can account for the make-up of the nuclei responsible for the "chlorineness of chlorine," the essence of what we now mean by "element?" It is a fascinating storv with many by-products beyond the information. For euample, the alchemists were neither fools nor charlatans when they meant imparting nobleness and color but said they were trying to "make gold," and even modern research cannot avoid the frustration of dead-end approaches, as witness the names "pandemonium" and "d el~rium" ' ' for elements 95 and 96 before their identifying separation by ion exchange techniques ($). The complementary introductory overview of a fundamental type of chemical reaction follows the general outlmes of Conant's case history method for the combustion story (3). Here again the familiar, the historical, and the philosophical intermingle,to culminate
in a sophistication of .concept appropriate for 1968. Students are surprised a t the clarity of thinking needed to write an "equation" for the production of copper from its calx by supplying phlogiston from charcoal. They smile less indulgently a t Lavoisier's listing heat as an element when they are asked whet,her antimony reacting with chlorine is a combustion after seeing the pyrotechnics in a darkened room. These introductory discussions serve several purposes. They trace the development of both the ideas and the procedures of the scientist. No outline of a scientific method is followed, yet each step of the typically scientific adventure is marked by the questions asked. Perhaps even most importantly, discussion ends with questions rather than final answers; doors are opened. Some promises of a return to more. detailed examination is given. Likewise, references to more exhaustive treatments of episodes in history, delineations between law and theory, or technological applications such as steel productions, etc., are provided. After these two rather whirlwind sight-seeing tours, we changepace rather abruptly and visit a "museum." We examine historically, the development of the atomic theory. I have found that this can be a fascination if approached from the questioning view, and not prolonged by inclusion of every detail. The dilemma of not being able to assign atomic weights from gravimetric data alone is much more interesting than the common sense validity of t h e laws of chemical combination. Some students even discover that arithmetical proportion is the same language whether used to describe copper combining with sulfur or for buying hosiery a t a department store. I also find this the best opportunity to introduce meaningfully such conveniences as exponential numbers. Often, "Gee Whiz!" problems help, such as the following The US. burns about 6 X lo8 tons of coal annually. A reasonable estimate is that this contains 3% sulfur. If recovered, the sulfur currently would sell for $50 per ton. Thus, how much could he spent annually to eliminate this major factor in air pollution?
This kind of question also serves as the take-off point for discussions of how technology is only one of the forces interacting in our society. The economics majors in the class are quick to point out the naivete in the answer, $9 X lo8. 1.8 X lo7 tons of sulfur would fill everything to the brimstone so that no one would want it at such a price. Our next concern is atomic structure. Here I somewhat abruptly abandon an historical approach, not only to save time, but also to offer a changeof pace. It is a rapid but connected trip from the Balmer lines in the hydrogen spectrum to the energy level pattern for H-like atoms to the Aufbau principle and the periodic table. The brief look a t the Bohr theory focuses only on his major revolutionary concepts: stationary states and transitions. The profundity of the DeBroglie relationship is emphasized with a minimum of Styrofoam. Hopefully, the students loosen their mental grip on the oversimplified, essentially Newtonian model of the atom. I also begin the struggle to get them to believe that there are limits to our "knowing." "The most probable" begins to replace "certainly." It seems to me important also at this point for students to begin to realize, sometimes as a Volume 45, Number 9, September 1968
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completely new idea, that nature never took the course! Our theories are the truly marvelous products of man's creation-and "explain" only within the self-consistency we have been able very pragmatically to apply. "Right or wrong" are less applicable labels than "more or less useful." Also the statistical basis for our statement of nature's laws makes an important distinction between the physical scientist's use of the term law and that so often encountered in social practice. The subject of nuclear phenomena seems to offer a good next consideration of these various new ideas. Radioactivity provides a t the same time unequivocal evidence for the particulate nature of matter, the necessity of considering energetics in mass conversions, the interplay of probability with causality, and the humility we must gain from realizing that nature will simply not let us control her completely. Nuclear structure gets re-examined in more detail. The demonstration of neutron capture by silver followed by beta emission to produce cadmium sets the stage for an appreciation of the mid-1930 attempts to make transuranium elements. The fission story follows with all its scientific glory and technological horror. Fallout we return to later, but "Fission, Fusion, and the Future" gets full treatment. The role of the physical scientist as a conserver of our natural resources and the fact that raising the level of underdeveloped countries means giving them an energy appetite get factual as well as philosophical scrntiny.
What I have described thus far is the part of my course which has changed the least over the years. It is appropriate at this point to make the second parallel emphasis implied by my title. This is to say that regardless of my own enthusiasms, the subject matter still has to appeal to the students. I feel strongly that since there is so much to choose from, the topics for concern should be those closest to the questions already in students' minds. For example, the amount of course time devoted to both information and implication of nuclear energy, e.g., the Pauling-Teller controversy, has steadily decreased in the past decade. The chemistry of life, what we know, and most importantly, where we stop knowing and begin to speculate, now looms largest in the minds of students asking the question, "What is science up to?" Thus the course has evolved so that the second half points in this direction. This exploitation of student curiosity is a technique we too often ignore. We forget that curiosity is childhood's science. We take a child with all those instincts for creativity-constant questions, vivid imagination, yes, even daydreaming-and for at least fourteen or even sixteen years insist on forcing answers upon him, often to questions he has never asked. The "education" coll~gestudents have is so riddled with pseudosophisticatio.n that almost invariably the matters that really are troubling the students come out with the apologetic prelude, "This may be a dumb question, hut . . . !" Of course we deplore this and certainly cannot overcome it all at once. What I am suggesting is that the content of a course such as we are talking about should be designed to deal with and certainly help the students formulate questions in areas where they are really curious. The by-product also is the allaying of 552
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fears-for again the tragedy of pseudosophistication in education is the attitude that the unfamiliar is both difficult and inherently harmful. The attack on the chemistry of life starts with what might be called a diversionary feint: consideration of the question of symmetry vemus asymmetry. We take a brief look at crystals and incidentally recognize the reasonableness of ionic bonding. In contrast to this type of aggregation we move next to the uniqueness of the carbon atom. The correlation between electronic structure, its predicted covalency, and the, "solid geometry" of a chemically active tetrahedron emerge. I have yet to fail in getting mirror images out of having five students assemble ball-and-stick models using four differently colored balls on a tetrahedral core. This leads us to Pasteur's experiments along the line he himself took. I admit to abundant cribbing from the fascinating tale Martin Gardner spins in his "Ambidextrous Universe" (4) even to swinging back into nuclear physics for the mental gymnastics of thinking about antimatter. The real campaign starts with some fundamental organic chemistry. Here I try to keep the emphasis on the unique consequences of carbon's characteristics: catenation, homology, isomerism, and the catholicity represented by the functional group idea. Both homology and structural isomerism are illustrated by the gasoline story. Even though it is almost ''ancient" history for present students, the crucial role of the branched chain in winning the Battle of Britain is a tiein to relevancy. We build a very limited vocabulary of functional groups: the double bond, alcohols, amines, and acids. These are sufficient for quite a bit of the grammar of typical reaction types: addition and the formation of esters and amides. Polymerization appears as an expected reaction for ethylene and the various vinyls. Even the remarkable catalytic consequences of introducing a Lewis acid or a free radical looks like a "logical thing for the molecules to do." Similarly, when the idea of difunctionality appears, condensation polymerization seems a reasonable next step beyond forming simple esters or amides. Once again, I might interject some comments about this "curiosity" thing. I have been impressed over and over again at how much relatively sophisticated chemical theory these non-science oriented students can assimilate if it is introduced by hanging on the hooks of relevancy. For example, when first discussing esterification, I am careful in my blackboard lasso- hemi is try always to rope off the oxygen from the acid. Never yet has the question, "Why do you do it that way and how do you know?" failed to come. Then and only then does the mumbo-jumbo of "polarization of the carbonoxygen bond" and "addition-elimination reaction" make any converts among the listeners. One of the real services such a course as this can perform for students is to take away some of the aura of the miraculous from the "miracles of modern chemistry" they constantly encounter in daily life. The girls, especially, seem to be quite fascinated to realize that hydrogen bonding gives tensile strength to Nylon, yet at the same time the absence of otherwise uninvolved electronegative atoms means that water molecules will form fewer attractions and allow Nylon garments to dry quickly. We finally get to the chemistry of life by this bigmolecule route. The chemistry represented by the
diagramatic manipulation of structures to build up the macmmolecules of biological interest, the carbohydrates, proteins, and nucleic acids is a consistent extension of what is familiar by this time. Protein structure consideration also recalls the observation of nature's asymmetry which impressed Pasteur so greatly. Digestion seems Yeasonable as a depolymerization process, along with the water solubility of the carbohydrate "bricks" (the Csnnits), each with its three uninvolved -OH groups. Also, by this time they are not so likely to be overwhelmed by the apparent complexity of structures such as DNA, but are willing to recognize new illustrations of now-familiar ideas; polymerization through esterification, the likelihood of hydrogen bonding by spatially matched purine groups, etc. The pattern of molecular-level genetics emerges. The dangers of fallout now seem meaningful. Also, questions are raised about the future possibilities of a molecular-level eugenics and the consequences for good or evil that such control would mean. The genetic code is, of course, an idea of great fascination but not easily understood. Fortunately there has been a great deal of excellent material prepared to present this subject. The Asimov selections in the reading book and Professor Sinsheimer's little pamphlet, "The Book of Life" (5) are totally understandable to most students. I have found in recent years that the question of the origin of life offers an admirable basis for summary as well as climaxing the course with an open-endedness typical of the scientific enterprise. By this time students have enough chemical information, hopefully to be able to distinguish between data and speculation. Also they now have enough science to appreciate some of the philosophical implications of our speculations. Of course, there are always some philosophy majors who never let facts confuse their discussion of issues, but most students are willing to be led to some depth in pondering how order came to evolve from disorder during eons of prebiological chemistry. My own physical-chemist predilections show through, too, by turning the final discussions onto entropy and the second law of thermodynamics. I have found Flanders' and Swann's delightful ditty1 in their "Drop of a Second Hat" to be an assist (6). (The first law received its due much earlier with combustion and E = me2.) We have a thoughtful time building the necessary fence around Clausius's "Welt" in order to validate the rest of his famous dictum. We also turn to Genesis 3: 19 (" . . . to dust thou shalt return") to answer the apparent paradox of life as an isolated violation of the second law.2
.. . and all the heat in the universe Is ganna. coooool down . . . . That's Entropy, man! a
A suggested topic for a final examination essay question mce
was (with proper tribute to Angrist and Hepler's "Order and
Chaos" (7)). The first time you heard of the second law of thermodynamics probably was at your grandmother's knee (or s t some equally respectable joint) when she told you the nursery rhyme of Humpty Dumpty. Typical of much folklore, this says much about human experience with eastastraphic irreversibility. Suppuse, after Humpty's misfortune, that Maxwell's Demon in the form of a hungry chicken arrived on the scene instead of all the king's horses and all the king's men. What could have happened?
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So much has been written about the humanistic values of science and by such profound thinkers that I hesitate to expound on this, the third emphasis suggested by my title. I hope that my point of view has already been recognized in what I have described thus far. My earnest hope--in fact, my main reason for considering this course important-is that students be able to recognize how science can contribute not only to man's comfort and health, but to his total sense' of values as well. This goal can be so easily missed if the intent is only to impart information. On the other hand, philosophical implications without some depth of understanding both the information and our means of getting it are usually so shallow as to be misleading. The mixing, hopefully even the blending, of knowledge and its application is'something that students have a right to expect of the manner in which a professor presents the material. A very important point to be kept in mind when dealing with today's student generation is that their idea of "culture" and ours may not coincide. Whether we like it or not, we have to face the fact that college-age young people do not see the world as we who have lived in it longer see it. I hope I am not falling into the trap of characterizing the whole by what I hear from the vocal minority. I doubt that one course can convert the acutely disillusioned-those who turn to the nihilism of the Hippie or the conventionality of the protester. But I do think we must speak to the many who are deeply concerned, profoundly puzzled by complexities in our culture that they do not understand. I t is a challenge, to help them sort out ideas from impressions, facts from opinions. This challenge is one that is made even more clear by dealing with a non-science major group. After all, if they were future scientists, at least we would expect predelictions nearer our own. These students put such a high priority on the contemporary that they seldom subject themselves to the discipline of historical development. They are not anti-intellectual in the sense of denying the rational, but they certainly give feeling a try first. I think we have to take a hard look at what this generation objects to before we either condemn or evangelize in the name of education. We owe some honest discussion to those who are convinced that our generation has dragged its feet in attacking the major problem of our time: making it possible for man to live with man. (Have we? There is an S in UNESCO!) They seem convinced that the establishment makes it impossible for individuality to flourish. (Does it? Nobel Prizes have been won by scientists in industry.) More specifically related to the subject here, they not only confuse science with what they consider to be misapplied technology, some develop their arguments after their minds are made up, not before.' For instance, my guess is that if asked to respond in a free association test to "Better Things for Better Living Through Chemistry," more non-science students would reply "Napalm" or "pollution" than would say "Dacron" or "conservation." Here, then is our problem! I have repeatedly mentioned my attempt to choose subject matter which is relevant to students because it is contemporary. Many of my own favorite themes have been dropped over the years: kinetic nlolecular theory, Volume 45, Number 9, September 1968
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stoichiometry via the mole, sulfuric acid production as an industrial barometer, and the GRS story from World War 11, to name a few. This is a small price to pay for the satisfaction I felt last January in finding that nearly every member of our class knew who Dr. Arthur Kernberg was. (The announcements in the press of the laboratory synthesis of a biologically active DNA came during our Christmas vacation.) Moreover, my grin was a mile wide when several students were critical of the press for hailing as a "synthesis of life" what really amounted to the laborious purification of an enzyme. This was the time to discuss the complexities of the problem of keeping a perspective on both means and ends, of the necessity for information before establishing legislation to control application, etc. This leads to deeper student thinking than rehash of Galileo's or Copernicus' essentially similar problems of centuries ago. A second theme that never is treated by an organized lecture, hut constantly receives attention is that scientists are human beings. Scientists have produced creative masterpieces t,o parallel any by the artist, musician, or poet. I n some cases these are the work of individuals, the Pasteurs or the Bohrs; more often they are the work of many, the teams led by Fermi or Carothers, for example. Still another human dimension, that of the concern the scientist has for the use of his knowledge, is represented by the founding of the Federation of At,omic Scientists which even in its embryonic stages was responsible for the establishment of the AEC by the McMahon Act. At times, the tenor of the class has suggested even more emphasis on this "science as a human endeavor." Few of the girls hold their preconceived prejudices after reading Laura Fermi's "Atoms in the Family" (8). Arthur Compton's "Atomic Quest" (9) does much the same for other students. James Watson's new book "The Double Helix" (10) will be suitable in this way also. Some find fascinating the subtler biographical implications of such a book as Linus Pauling's "The Architecture of Molecules" (11). Another theme which gets continuous rather than concerted attention is that it is virtually impossible to separate science from technology. The idea that scitmw may bt. pond for our culturr bnt r l ~ teehndn~\f t is susneet seems to me 10 be the f:~ll:~ciou.; thinkinr that may even come as a disservice from courses on the philosophy of science. The "purity" of scientific research is a fiction everyone who has done research recognizes. Certainly, technological progress depends on scientific knowledge. But the complementary dependence of scientific advances on the feedback from technology needs at times to he pointed out. Likewise the idea that industry is something else than science: science seeks truth, but industry seeks only a profit by selective exploitation of science, has to be eradicated by cited examples (plastics, rubber, and nuclear power are three good choices). Another myth that needs exploding is that some kinds of knowledge are had, and others are good. Even worse is the idea that the search for knowledge can he $See, for example, the report "Education and the Spirit of Science" issued by the Educational Policies Commission of the National Education Association, 1201 Sixteenth Street, N.W., Washington, D. C. 20036 (1966).
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good or had depending on the use to which knowledge is put. This view is so foreign to the scholar-investigator that we often forget how deep seated it is in so many otherwise educated minds. I have been jolted by this so often that I now anticipate it and repeatedly try to give illustration to the statement, "There never has been a discovery of physical science that has not strengthened the hand of the Good Samaritan" (Conant's phrase) (If). Knowledge can be used either for good or evil; what may be an initial terror may become an eventual blessing and vice versa. Nuclear fission to conserve fossil fuels, nerve gases in cancer therapy, shift the view one direction. DDT and ecological damage, internal combustion engines, and air pollution shift it in the other. A final comment about the aims of a science course for non-science majors: I believe it should help students to realize that science does have a contribution to make toward what men call ethics or a sense of value^.^ Certainly this contribution is not the fantasy that the scientific method (whatever that is?!) will solve mankind's problems as soon as the politicians and social scientists learn it. Nor is it simply that science through technology will be able to supply food, water, replaceable human organs, and even living space on another planet. Rather it is the spread throughout all human endeavor of some of the attitudes essential to the scientist in his approach to problems. The insistence on completeness in communication (discussing the shift to the ClZscale of atomic weights is the time to bring this in), the abhorrence of provincialism (naming the elements illustrates it early in the course), the reliance on the rational (every day furnishes examples), and the essential humility of the struggle to understand nature (the principles of impotence such as uncertainty and the second law of thermodynamics give this great suhstance) are only a few specifics. Thus I see a course such as this to be a unique opportunity to confront students with both information and questions. I think their criticisms of our culture are legitimatebut born more from shallowness and inexperience than from analysis in depth. Those who have a sense of futility may well base it on the mistaken idea that the answers we now have are more important than the questions yet unanswered. If so, we owe them enlightenment. That is what a course in science for the non-science major must provide. Literature Cited (1) YOUNG,LOUISEB. (Ed.&?), "The Mystery of Matter," Oxford University Press, New York, 1965. (2) SEABORQ, GLENN T., "Man-made Trsnsursnium Elements,!' Prenbice Hall, Inc., Englewood Cliffs, N. J., 1963, p. 16. (3) CONANT, JAMESB., "On Understanding Science," Yale Universit.~Press, New Haven, 1947, Chapter 111. (4) GARDNER,M., "The Ambidextrous Universe,'' Basic Books, Ine., New York, 1964. (5) SINSHEIMER, ROBERTL., "The Book of Life," AddisonWesley Pub. Co., Reading, Mass., 1967. AND DONAID,"At the Drop (6) FLANDERS, MICHAE ~ SWANN, of Another Hat," Angel Records. (7) ANQRIST, S. W., AND HEPLER,L. G., "Order and Chsns, Laws of Energy and Entropy," Basie Books, Ine., New York, 1967. (8) FERMI,LAURA,"Atom in the Family," Phoenix Books, Universitv of Chicaeo Press. Chiesm. 1954. (9) COMPTON, H., "At& QU&" 0;f&d University Press, New York, 1956.
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(10) WATSON, J. D., "The Double Helix," Atheneum, New York, 1968. (11) PAULING,L., AND HAYWARD, R . , "The Architecture of
Molecules," W. H. Freeman Co., San Francisco, 1964. (12) CONANT, JAMESB., "Modern Science and Modern Man," Donbleday Anchor Book?, Garden City, New Yark, 1953, p. 186.
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