VOL.2, No. 11
THE
OBIECTIVE~ IN TEACHING CHEMISTRY
987
OBJECTIVES in the teaching of chemistry are necessarily extremely diversified. They are influenced by the maturity of the students, by the function and even the location of the school in which chemistry is taught, and by the branch of the subject under discussion. The most important problems in the pedagogy of any field relate to elementary teaching-in chemistry, to its presentation in high schools and in first-year college courses. With your leave, I shall limit myself to the latter. The objectives of which I shall speak are attained more readily if the freshmen have already had considerable contact with the subject before admission to college, preferably through the medium of a high-school course, but the fundamental problem remains the same whether this is the case or not. Even with these limitations, there are many phases of the subject which ould be taken up. I wish to speak of chemistry, not as an isolated subx t , but as a part of the general training which our colleges and univerd.ies are attempting to give to their students. This training has received very severe and apparently well justified criticisms both from within and from without academic circles. We are told that the average college g-aduate is neither educated nor efficient. Those who speak in general terms say that the college man, after leaving school, does not take his place as a leader in political, civic, religious affairs as he should; those who criticize specifically the students preparing for some specialty, such as
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JOURNAL OP CHEMICAL EDUCATION
N~VEMBZR, 1925
chemistry, do not complain that our students are lacking in knowledge, but emphasize the lack of ability to use the knowledge acquired. These criticisms directed against our college graduates are similar t o observations made by foreigners on American men and women in general. I have repeatedly heard well informed visitors to our country express the greatest admiration for the energy, the determination, the ingenuity, the honesty of our people, but have a t the same time heard their astonishment a t our lack of reflection. And while the qualities which we are said to possess so fully have been of the greatest value in the pioneering stage of our histoiy, they will not lead to the greatest happiness nor the greatest success in the era upon which we are now entering-an era in which careful use of what we have left must replace the extravagant exploitation of what seemed unlimited natural resources. To solve our future problems, careful thought will be needed; to live happily and contentedly when our riches become more limited will require greater dependence upon intellectual pleasures rather than on those which are bought with readily acquired wealth. In no country has the change from the pioneering age to that of husbanding of resources come so rapidly as in ours, and no people have had to adapt themselves to new conditions so quickly as ours. In this adaptation our schools must play an important role. It seems to me, therefore, that whether we are considering liberal education, the purpose of which is to develop as fully as possible the student's ability to draw from within himself the seeds of contentment and happiness and to function as a useful member of society, or whether we are discussing specialized professional training, we must set as our aim the development of intellectual power rather than the accumulation of facts. The acquisitive age is the highschool age-when the student has stepped beyond this period he should be equipped with a storehouse of facts large enough to be the basis for a career of generalization and of speculation. It is interesting to note that the general criticisms directed against our modern college and university have revived an interest in the classics and humanities as contrasted to the sciences. I have no objection to thes subjects in our curricula-I do not regret for a moment the fairly larg amount of time devoted to them in my own education. But to reope the discussion of the advantages of either humanities or sciences in co tributing to a liberal education seems to me the height of absurdity. is like a discussion I once heard carried on in all seriousness as to which topics in chemistry do, and which subjects do not contribute to a liberal education. Subjects and topics have nothing to do with the matter a t all any subject and any topic is the source of an education in the broadest sense of the word if the presentation is correct. The most cultured, the really educated man finds mental stimulus in every subject, in every fact
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VOL. 2.
No. 11
OBTFCTIVES IN TEACHING CREMISTRY
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because he is trained to see each fact in its relation to thousands of others. Now what I wish to maintain is that chemistry is peculiarly well suited to play an important role in the education of our younger students, whether they are professionally interested in the subject or not. It possesses certain phases susceptible of mathematical analysis, and thus gives opportunity for training in the type of reasoning employed in the most exact sciences. But not all reasoning is mathematical. And there are many relations in chemistry which today are based on a more generalized type of reasoning than that usually called mathematical. Finally, chemistry shares with other experimental sciences the educational advantage that it may he used to train students in the habit of checking conclusions against facts (which we call experiments). The social and historical sciences can afford this training hut rarely-in our subject it is an everyday experience. It is perhaps hardly necessary to point out topics in chemistry especially well suited to carrying out this type of training through chemistry. But I should like to point out how very often a slight change in,the emphasis in teaching this or the other topic may entirely alter the nature of the henefit derived. In the presentation of molecular and atomic weights it is, of course, necessary to acquaint the student with the methods of determining these quantities. It is obvious, also, that the success of our teaching must be tested by prohlems consisting of calculations of molecular and atomic weights from experimental data. But a student may be quite expert in making such calculations and yet know nothing about atomic weights. I believe that we often stress too much the doing of prohlems and neglect making sure that the underlying principles are appreciated. Few subjects are more fruitful in valuable training than this one. Consider what the comprehension of atomic weights means: first, the understanding of the reasons why an arbitrary unit could be made the satisfactory basis for expressing the weights of molecules although its value in ordinary measures was not known till recently; next, the modern basis of Avogadro's law; then the rational assumptions about the possible numbers of atoms in various molecules and the dependent deductions about the weights of the elements in unit volume of gaseous compounds; finally the check on the correctness of these assumptions by the facts. Here is a sequence of reasoning, experiment, deduction, and check which might seem to the superstitious to he made especially for the purpose of teaching students how to think. Another point of extraordinary value is the comparison of properties of substances with their uses. I believe that descriptions df the uses of various chemicals particularly to students who have had a year of highschool chemistry can he greatly overdone. Suppose the student has for-
gotten the u s e s i s there any reason to suppose he will not forget them again, and what harm if he does? But it is training of the highest order to describe to the class some of the chemical properties of a substance, such as nitric acid or, even better, some less well-known reagent, and then to demand a list of possible uses. If the student is to become a chemist, the value of this type of training is obvious for a large part of his work will consist of the selection of proper reagents to accomplish a given purpose. But even if he is not to be a chemist, the training will be just as valuable for, after all, the selection of a man for a job, the selection of a plan for a house, yes, even the selection of a girl for a wife is a matter of making sure that the properties are adapted to the purpose. Although there are hundreds of other examples I shall mention but two,. chemical equilibrium and the periodic system. With freshmen, I prefer to treat the former topic in its simpler forn-Le Chatelier's rulebecause I believe that a general understanding of effects should precede mathematical treatment. But be that as it may, can you think of a more valuable training in logic, a more convincing demonstration of the value of exact experimentation and of the usefulness of checking up theory by fact than is afforded by the study of equilibrium as illustrated in the contrast between the methods employed in the synthesis of ammonia and of nitric oxide? Here the student can very clearly realize the folly of wild experimentation which lacks guiding principles, the value of forethought and well defined plans of search in contrast to haphazard guessing; here he can see the immense value of scientific theory to human welfare; here he can learn of the necessity of checking up every hypothesis by fact. How many failures in business, or even in life, are due to enterprises based on illfounded hope instead of investigation, a n d how valuable a training which discounts baseless hopes and substitutes for them the habit of careful and, patient inquiry. The periodic system, on the other hand, provides another type of mental training. Many a college student is intellectually swamped by the mass of facts he has acquired and must continue to learn. The only hope of escaping from the wilderness is to find some means of coordination. Even if the periodic system were nothing more than an illustration of such coordination its value would be very great for the college student. But i t is not sufficientto devote an hour or two to it a t the end of the course, nor t o mention i t earlier and then to leave it severely alone. The facts of chemistry must be built on it as much as possible. And this treatment is of value in another direction; there are facts which do not fit well into the system. To arouse the critical spirit in our students, to show then1 the inadequacy of present-day knowledge and theories is but another way to make them think. If, in my enthusiasm for the intellectual training of students thrclugh
chemistry, I have given the.impression that I derogate the descriptive or factual side of the subject, I have not done what I intended. For chemistry is, of course, a science and, therefore, an orderly, systematic collection of facts. It is indeed a very practical science and that should not be lost sight of. But emphasis has repeatedly been placed in our discussions on this phase of chemistry, perhaps too frequently from the point of view of the particular class of students for whom I speak. It is on this account that I have spoken entirely on the other s i d t t h a t of intellectual training. If our students can learn to think, if they can be trained to use what they know, if they develop judgment in our hands, we shall turn out a product both useful and successful, happy, and contented. And if that product is to be transformed into chemists, the transformation will be a very simple one.
