The
CULTURAL, or PANDEMIC, CHEMISTRY COURSE after SIX YEARS of TRIAL* JOHN A. TIMM Yale University. New Haven, Connecticut
This @per contains a review of the author's six years of experience teaching a course of the "pandemic" type; i. e., one designed for liberal arts students who do not intend to elect advanced chemistry courses. Experiments i n instruction methods, chmce of subject matter, laboratory assignments, seminar groups for better students, and the probkm of the student who decides to take further chemistry courses are discussed. The growth of Gndemic courses i n this country is reviewed.
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WELVE years ago the author had the pleasant experience of assisting the late Professor Boltwood teach several small groups of liberal arts students in Yale College. These students were preparing for no further courses in chemistry so that greater freedom was possible in the choice of subject matter than in the usual type of elementary chemistry course. This modest attempt was, as far as the author knows, the first toward the goal of a special type of chemistry course for the strictly non-professional science student. Then in 1926' there appeared in the JOURNAL OF CHEMICAL EDUCATION the pioneer paper on the subject of cultural chemistry courses by Professor Bancroft of Cornell in which the name "pandemic" chemistry was first suggested for this type of course. In the same year the author organized a course a t Yale to meet this need. In the fall of 1928 a t the Swampscott meeting of the American Chemical Society, this Division held a symposium on pandemic chemistry. Here two types of courses were suggested; one in which the applications of chemistry were to receive major emphasis and another in which the philosophy of the science was to be stressed. Several objections were raised in the discussion. Many thought the first type of course too easy and the second too difficult. A considerable number could see no reason for giving such courses a t all. Six years have passed and during them considerable experience has been gained with this type of course. The results can now be given where formerly only opinions could be expressed. During these years several textbooks, which have made the task of organizing such * Presented before the Division of Chemical Education of the A. C. S. at Washington, D. C., March 29,1933. BANCROFT, "Pandemic chemistry," J. CHEM.EDUC.,3, 396 (April. 1926).
courses considerably lighter, have appeared. The growth in their number has been surprising. From perhaps five a t the time of the Swampscott meeting the number has grown to a t least ninety a t the present time. These are offered not only a t many of the larger uaiversities but also a t a considerable number of small colleges. The author's experience has been exclusively with that type of pandemic chemistry course in which the philosophy of the science has been the basis of the order of presentation of the subject matte^.^ The fundamental theories of chemistry have been studied in the following order: first, those of the structure of matter from its states to the ultimate electrons and protons (or had we better say, negatrons, positrons, and nentrons?) ; second, the theories of the nature of changes in matter and of equilibria; third, the solution theories including that of electrolytic dissociation; and, finally, organic chemistry. When a given theory is to be discussed, the experimental evidence, upon which it is based, is brought to the student's attention. The theory is then weighed in the light of this evidence and its reliability subjected to question. Finally the manifold applications of the theory to the development of natural resources, to the chemical industries, and to the daily life of the individual are discussed. Consider as an example the theory of electrolytic dissociation. The factual evidence for its validity, which includes disobedience of the solution laws, electrical conductivity of solutions of electrolytes, Faraday's laws of electrodeposition, and the nature of reactions between electrolytes, is first discussed. The original Arrhenius theory is applied to the explanation of these phenomena. Its failure to explain the behavior of strong electrolytes is pointed out and the modern extensions of the theory are discussed. Then its many applications receive attention: e. g., acids, bases, and salts; neutralization, hydrolysis, and precipitation; analytical chemistry; the heavy chemical industries and the economic importance of such substances as sulfuric and nitric acids, soda ash, caustic soda, lime, and ammonia; electrolysis and the electrochemical industries; electrochemical cells and the problem of corrosion. This method of presentation engenders a greater respect for the science of chemistry than any recital of its manifold accomplishments only.
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2 T ~ M "An , experiment in chemical education at Yale," ibid., 6, 1316 (July-Aug., 1929).
The synthetic ammonia process means far more to any student after he has studied the effect of temperature and pressure changes on equilibria and catalytic action. In the reading periods the students are given the choice of reporting on one of several chemical industries or on some theory which has been discussed. In one of these periods over half the class read such books as Eddington's "Nature of the Physical World" and Darwin's "New Conceptions of Matter," whereas a lesser number reported on such topics as the petroleum or the iron and steel industry. One of the most valuable opportunities that a pandemic course offers to the teacher is that of experimenting with a wide variety of new topics. The obligation to cover certain material prerequisite for advanced courses has been removed. Some of the topics used may seem too difficultto those who have not tried teaching them, perhaps because they are normally discussed with graduate students only. However, upon attempting to teach them they have appeared to the students no more difficult than such an old favorite as Dalton's atomic theory. For example, no one can deny the great importance of the quantum theory to modem physical chemistry. Yet few teachers of elementary chemistry have found time to discuss its importance with their students. Many believe it to be too difficult a concept to be attempted. The author has found that the simpler aspects of the corpuscular and the wave theories of both energy and matter can be understood by the average liberal arts student and that they have a greater cultural value than a discussion of, for example, solubility product or a city gas plant. The cost of giving such a course is of interest especially a t this time of reduced departmental budgets. Since it makes possible a segregation of the liberal arts from the science students, the former can be handled in large lecture sections because individual drilling and quizzing are unnecessary. The author meets nearly three hundred men three times a week in two lecture sections. With assistance in pading the ten-minute papers, which are givcn wcrkl!; and the reading period rc.umts this numbc.r of men can be handlcd eficientlr. ~ i r h a p the s best distribution of time from the studen& viewpoint would be two lectures weekly to large sections and a third period devoted to discussion in which small groups meet under an instructor. The laboratory may well be made optional or not be offereda t all. It bas been the author's experience that the majority of liberal arts students find chemistry laboratory work distasteful. Deplorable though this attitude may be, the fact must be faced that it results in the almost complete failure of such students to benefit by their laboratory experience. At Yale some 40 out of
300 students elect the optional laboratory coufse. In so far as possible the policy bas been to assign a simple problem for each exercise and to allow the stndent to work out the details of the experimental prgcedure for its solution. For example, when electrochemical cells are to be investigated, each student is given some eight electrodes of different metals, a choice of solid salts of these metals, a porous cup, and a voltmeter. He is told to make up cells of different pairs of metals, to vary the concentration of the electrolytes in each side of his cells, to measure the electromotive force in each case, and finally to explain his results. Problems of this sort avoid the usual "cook-book" type of directions. For the past two years we have been experimenting with seminar groups of better students who are willing to do extra work with no additional credit. The results bave been most gratifying. A topic is selected and the material is divided between two students. Each prepares a half-hour paper which he presents before the group. Such topics as modem methods used to discover new elements, the detection of an isotope of hydrogen, methods of investigating the structure of alloys, X-rays and crystal structure, the hormone, insulin, and many others bave been discussed. Two reasons perhaps more than others have dissuaded many elementary chemistry teachers from organizing a pandemic course. On the one hand they believe that such a course must necessarily be made less difficult than the traditional type, and on the other they do not know how to solve the problem of taking care of the student who becomes so enthusiastic about chemistry that he changes his mind and decides to take advanced courses. The pandemic course can be made as difficult as the instructor cares to make it. Such topics as the use of X-rays to determine crystal structure, the photoelectric effect as a proof of the validity of the quantum theory, the origin of spectra, electron diffraction by crystals, and the modern theories of the behavior of electrolytes in solution are in no sense easy. But if interest be maintained by illustrations of their philosophic or practical importance, they are not beyond the powers of the average liberal arts student. The problem of the student who decides to go on with chemistry after taking a pandemic course has been exaggerated. If a t the outset all students who have any doubts as to their field of major interest are sent into the regular elementary course, only very infrequently will such cases arise. When they do, the ability of the student must decide whether he is to be permitted to go on. With a background of sound fundamental theory, the superior student can be safely allowed to take advanced courses. The inferior student should not be permitted to do so.
THE photograph of the van't Hoff panel which appeared on the frontispiece page of the June JOURNAL should have been credited to Dr. Avery A. Ashdown, though it came to us through Dr. Newell's hands. We are indebted to Dr. Tenney L. Davis for the information that the bronze plaquette bearing van't Hoff's likeness is a reduced replica of a marble basrelief in the corridor of the van't Hoff Laboratorium at Utrecbt.
