THE USE OF HISTORY IN TEACHING CHEMISTRY GLEN WAKEHAM University of Colorado, Boulder, Colorado
ONE
RECENTLY appearing device for "culturizing" science teaching is to make occasional references to scientific history and to garnish the text with portraits of eminent scientists, along with photographs of wrecks, fires, explosions, and other spectacular catastrophes. I t was left to President Conant to point out that an intelligent "understanding" of science might be most effectively achieved by developing the subject upon an historical basis [AmericanScientist, 35, 33 (1947)l. Textbook writers are almost always mature scientists. They have mastered, organized, and synthesized the subject matter into what seems to them to he a coherent, logical whole. They have probably long since forgotten the sequence .of comprehensions through which they travailed in achieving a mastery of their specia1 science. They ignore the fact that few undergraduates have logical minds. ,They assume that the average elementary student can comprehend, at first exposure, a clear, well-organized presentation. They are prone to unload upon the hapless freshman a formidable fraction of all they have accumulated in many years of concentrated effort. As the great majority of beginning chemistry students will never go on with the subject nor use chemical knowledge technically or professionally, it is a waste of their time to require them to absorb masses of chemical details for subsequent regurgitation in examinations. I t is far more suitaljle to their needs to lead them into an "understanding" of the science. President Couant suggests that this can he achieved by the skillful presentation of carefully posen topics, set in their historical and philosophical background. Most students enjoy a well-told tale and get the meaning of a scientific law or theory more easily from an apposite illustration than they do from an impeccably logical definition. Of more general application is the plausible-admittedly unproven-"heuristic" theory, based upon evolutionary precedent, that the immature, developing individual human mind will more readily comprehend any body of scientific knowledge if the various topics are presented in the order of their appearance in history rather than on any strictly synthetic or analytical plan. In spite of their occasional polite bows in the general direction of scientific history, most textbook writers fail to use the historical method in any systematic way. They also ignore the fact that most immature students are impressed by the association of ideas and the order and juxtaposition of topics in the text. "Horrible
examples" of this type abound in recent texts. One charmingly written book starts out with the theory of . atomic structure, makes a small-type reference to the Periodic Law, and devotes the last chapter to a description of radioactivity. I t should he unnecessary to point out to a mature chemist that in most cases observation and recording of facts precede the formulation of explanatory theories. After this textual defiance of the inductive scientific method one cannot blame the numerous students who reported that the Periodic Law mas devised to explain atomic structure, while atomic structure suggested radioactivity. Physical science abounds in beautiful sequences of theories and laws which grow naturally out of a succession of observations. In the paper referred to above, President Conant demonstrates in detail how one can proceed in a fascinating manner, following the sequence Galileo, Torricelli, Viviani, Pascal, von Guericke, culminating in the final lam of Boyle and illustrating, also. the philosophy of science in a way which almost any normal student could grasp. Any one who has read even cursorily the history of chemistry can think of other, equally effective, sequences. Horn relatively easy it is to get students really to understand the law of mass-action if one begins with the Essai sur chemie statique and follows through, in chronological order, the work of Wilhelmy, Sainte Claire de Deville, Berthelot, .Guldberg, and Waage, layingthe foundation for a gznera1 discussion of dissociation on t h e readily observed behavior of gases (where the theory really nrorks!) instead of starting out with demonstrations of the electrical conductivity of solutions of electrolytes and obfuscating the student with explanations of why the law works only approximately for certain types of solutions and not at all for others. _To the writer's personal knowledge, hundreds of students subjected to the current order of presentation get firmly fixed in their minds that ionic dissociation is caused by the electric current. The most spectacular scientific sequence, of course, is the development of sub-atomic physical chemistryBecqerel, Thompson's "electrons," the Curies, Rutherford, Bohr, Moseley, etc., down to Lise Meitner and Bikini-a dramatically irresistible evolution leading up to a stunning climax. But to begin an elementary chemistry course with the theory of atomic structure and end it with a description of radioactivity is hardly less than a logical and pedagogical outrage-like reading Hamlet backwards.
