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TEACHING PHYSICAL CHEMISTRY-FORTY YEARS OF CHANGE' FARRINGTON DANIELS University of Wisconsin, Madison
S O M E of the addresses of those receiving former Norris avards as published in the JOURNAL OF CHEMICAL EDUCATION seem to indicate that one is quite free to do some reminiscing. This privilege I shall accept. My first chemistry teaching was as a graduate assistant at Minnesota and later at Harvard. When an expected postdoctoral fellowship in Germany did not materialize because of World War I, I began my lifelong teaching of physical chemistry, first at Worcester Polytechnic Institute. At Worcester Tech I was learning how to teach physical chemistry and doing some research when the latter soon changed over into war research. Eventually I went into Chemical Warfare Service and worked with C. A. Kraus. Later I went to Washington to do research on nitrogen fixation under the direction of Lamb and Tolman. I t was here that I started work on the kinetics of the nitrogen oxides which I have followed ever since. I n 1920 I accepted an assistant professorship in physical chemistry at Wisconsin with the hope of applying the then promising radiation hypothesis to chemical kinetics. It was a short-lived hypothesis but it did stimulate active research on the kinetics of gas phase reactions. At Wisconsin I was to teach physical chemistry, a graduate course in advanced physical chemistry, and a new course in calculus for chemists. I had never had a course in calculus; its importance was not realized in those days. But I kept one step ahead of the class and became much interested in the subject. I finally worked the course up into a hook, "Mathematical Preparation for Physical Chemistry," published in 1928. The book is still used by students in other fields who have to learn something about physical chemistry. I find that among biologists I am known for this book. I remember in the first year, after I had failed some students in this course, one of the older professors came t o me in high dudgeon and told me how useless he thought mathematics was for real chemistry and particularly for his students. I remember one more incident in connection with my early missionary efforts to put more mathematics into chemistry. As Chairman of the Division of Physical and Inorganic Chemistry of the A.C.S., I organized a symposium on Mathematics in the Service of Chemistry, with Fowler, Dushman, Urey, and others. We were assigned to a room holding - about 100. When the time came the
'From the address delivered on the occasion of the James Flack Norris Award by the Northeastern Section of the American ~~~~~b~~ 15, Chemical Society in Cambridge, ~essrtchus~tts, 1957.
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elevators kept pouring chemists into the room and hallways so that after much confusion aud delay we were transferred to a larger room--all 600 of us! The laboratory course in physical chemistry a t Wisconsin was quite a challenge. At first I had to learn much from my laboratory assistants. We tried out many new experiments, and after several years of practice with mimeographed directions, the first edition of Daniels, Mathews, and Williams appeared in 1929. In this book (now in its fifth edition) me have avoided the imperative mood. We do not command the student to do anything. For each experiment we include suggestions for further work, hoping to challenge some of the better students. It is interesting to spot the "doers" i h o siy, "Show me what to do so I can get it done and get out of here," and the "thinkers" whose curiosity is aroused and who linger on to question and test some doubtful point or who get an idea for testing out an hypothesis of their own. We assign enough time to allow leeway for extra work. We insist on complete and critical, well-written reports and usually manage an oral quiz on the experiment and report. There are problems in planning the most effective laboratory course in physical chemistry. How far should one go in buying ready-made machines, in leaving the potentiometer connected, and in making up the standard solutions? To what extent should each student set up his own apparatus starting from scratch? We used to insist that all students be able to do simple glass blowing. Crowding of classes and greater efficiency forces us to the more automatic, fool-proof apparatus, but valuable experience and the development of resourcefulness thereby are crowded out. I was soon assigned to teach physical chemistry to a section of engineers. We vere using the third edition of Getman's "Theoretical Chemistry" which was largely based on Nernst's "Theoretical Chemistry," as were all physical chemistry textbooks of the time. For Getman's fourth edition I helped extensively in makiug suggestions and in correcting proof. I n 1928 the publishers asked me to make a complete revision for the fifth edition. I did not know what I was in for! Five editions of this book have kept me busy. It takes a couple of years to revise a book and a year to carry it through the press. Writing two such books with new editions every five years is a perpetual job requiring many evenings, most vacations, and much family sacrifice. As the editions progressed, helpful suggestions came from chemists around the world, I am greatly indebted t o my associates at the University of ~ i s c o n s i u and to many teachers in other universities and colleges. ~~
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JOURNAL OF CHEMICAL EDUCATION
I n the last edition of "Physical Chemistry," I enlisted the help of my associate, Professor Robert A. Alberty, to share the responsibilities and the drudgery of revision. TRENDS IN TEACHING OF PHYSICAL CHEMISTRY
What have been the trends and the influences in the teaching of physical chemistry over the last forty years? Physical chemistry, as a separate branch of chemistry, was born in 1887, when the publicat.ion of t,he Zeitschrift fiir physikalische Chemie began with articles on electrochemistry and kinetics by Ostwald, Arrhenius, and Nernst. I have been able to observe most of the development of physical chemistry and have taught it half of its 70 years. When I was introduced to physical chemistry it emphasized atomic and molecular weights, dilute aqueous solutions, molecular structure, and properties of interest t o organic chemists. I t has been interesting to see in each decade the greater emphasis on the more quantitative approaches -more use of mathematics and greater accuracy in experimental measurements through improvement in apparatus. In each decade new discoveries have enriched physical chemistry and the teaching area has widened. I n writing a physical chemistry text, after a while one reaches a steady state of book pages beyond which it is not easy to go because of limits in the students' time and financial resources. For each addition of new material there must be subtraction of old material, and the rejection of obsolete material is difficult and painful. Fortunately, much of the simpler material has now been taken over by the more elementary courses, thus leaving room for new and more advanced material. The influence of physics on physical chemistry is clear. Radioactivity, spectroscopy, Raman effect, X-rays and crystallography, isotopes, atomic fission, and nuclear magnetic resonance have found immediate inclusion in physical chemistry. Engineering needs have led t o improved distillation of liquids, phase diagrams, chromatographic adsorption, and infrared absorption spectra. I remember in 1936, at an M.I.T. conference on spectroscopy, pointing out the limitation of spectrophotometric analysis in the visible and urging that more attention be paid to infrared absorption spectrophotometry. The greatest advances in physical chemistry have come from the abstract reasoning of scientists like Willard Gibbs, Albert Einstein, G. N. Lewis, Peter Debye, and others. G. N. Lewis has exerted perhaps
VOLUME 35, NO. 7, JULY, 1958
the greatest influence on the development of physical chemistry particularly in the fields of chemical thermodynamics, partial molal quantities, ionic strength, the electron pair and atomic and molecular structure, and in the concept of acid strength. Physical chemistry serves all other branches of chemistry and is itself composed of many different parts. I t is helpful to recognize three fundamental approaches. Thermodynamics is reasonably complete in principle and is exact in predicting equilibrium conditions. Chemical kinetics is concerned with reaction rates and mechanisms, and there is much still to be developed in its practical applications to chemistry. Molecular structure is helpful in predicting gross chemical behavior from a knowledge of the individual molecule. New developments in any one of these branches of physical chemistry find applications in many other fields. An important new trend in physical chemistry, as in all sciences, is a realization of the social responsibility of the scientist. As civilization develops and becomes more complicated with atomic bombs and other powerful forces, which can be used either for improvement or destruction, it becomes more and more dependent on the scientist. The views of the scientists and the teaching of science must broaden with the new responsibilities and the awakening of a social conscience. For years I have tried to educate the scientific public on the possibilities of solar energy. In 1953 I arranged a symposium at Madison, attended by about 30 experts from around the world. I n 1954 the symposium arranged by the Indian Government and UNESCO in Delhi also involved about 30 scientists. The symposium in Arizona in 1955 attracted about a thousand scientists, engineers, industrialists, and newspapermen. Interest in solar energy is increasing rapidly, but there are mostly unsolved problems. The present need in the non-industrialized countries for solar cookers, solar heating, solar refrigeration and cooling, solar engines, solar distillation of salt water, the direct production of electricity, and other devices are challenaes -. whose answers are still in ex~erimental stages. I n closi~g,I would like'to point out the challenge in the proper teaching of physical chemistry. If teachers in the United States usually pitch their classes to the average student, the superior students frequently will not be given sufficient stimulation. Certainly we have to educate many people, but we want also to draw out the best in the best students. The challenge is in trying to meet this double responsibility.
