College Teaching Part 11

44, page 372. 1894.

FARLOW, W. G. Biological Teaching in Colleges. _Popular Science Monthly_, Vol. 28, page 581. 1886.

HARVEY, N. A. Pedagogical Content of Zoology. _Proceedings National Education a.s.sociation_, 1899; page 1106.

HODGE, C. F. Dynamic Biology. _Pedagogical Seminar_, Vols. 11-12.

HUXLEY, J. H. Educational Value of Natural History Science. Essay II, _Science and Education_. 1854.

RUSK, R. R. _Introduction to Experimental Education._ Longmans, Green & Co., 1912.

SAUNDERS, S. J. Value of Research in Education. _School Science and Mathematics_, Vol. II, March, 1902.

SMALLWOOD, W. M. Biology as a Culture Study. _Journal of Pedagogy_, Vol. 17, page 231.

WELTON, J. _Psychology of Education_ (chapter on "Character"). The Macmillan Company, 1911.

Footnotes:

[2] These problems relate particularly to the introductory courses.

V

THE TEACHING OF CHEMISTRY

=Preparation of entering students a determining factor=

Some of the students entering cla.s.ses in chemistry in college have already had an elementary course in the subject in the high school or academy, while others have not. Again, some study chemistry in college merely for the sake of general information and culture, while many others pursue the subject because the vocation they are planning to make their life's work requires a more or less extensive knowledge of chemistry. Thus, all students in the natural sciences and their applications--as we have them in medicine, engineering, agriculture, and home economics--as well as those who are training to become professional chemists, either in the arts and industries or in teaching, must devote a considerable amount of time and energy to the study of chemistry. The teacher of college chemistry consequently must take into consideration the preparation with which the student enters his cla.s.ses and also the end which is to be attained by the pursuit of the subject in the case of the various groups of students mentioned.

In the larger high schools courses in chemistry are now quite generally offered, but this is not yet true of the smaller schools. In some colleges those who have had high school chemistry are at once placed into advanced work without taking the usual basal course in general chemistry which is so arranged that students can enter it who have had no previous knowledge of the subject. In other words, in some cases the college builds directly upon the high school course in chemistry. As a rule, however, this does not prove very successful, for the high school course in chemistry is not primarily designed as a course upon which advanced college chemistry can be founded. This is as it should be, for after all, while the high school prepares students for college, its chief purpose is to act as a finis.h.i.+ng school for those larger numbers of students who never go to college.

The high school course in chemistry is consequently properly designed to give certain important chemical facts and point out their more immediate applications in the ordinary walks of life, as far as this can properly be done in the allotted time with a student of high school age and maturity. The result is consequently that while such work can very well be accepted toward satisfying college entrance requirements, it is only rarely sufficient as a basis for advanced college courses in the subject. As a rule it is best to ask all students to take the basal course in general chemistry offered in college, arranging somewhat more advanced experiments in the laboratory wherever necessary for those who have had chemistry in preparatory schools. This has become the writer's practice after careful trial of other expedients. The scheme has on the whole worked out fairly well, for it is sufficiently elastic to meet the needs of the individual students, who naturally come with preparation that is quite varied. Almost invariably students who, on account of their course in high school chemistry, are excused from the general basal course in college chemistry have been handicapped forever afterward in their advanced work in the subject.

=Organization of first-year course--General chemistry=

The first year's work in college chemistry consists of general chemistry. It is basal for all work that is to follow, and yet at the same time it is a finished course, giving a well-rounded survey of the subject to all who do not care to pursue it further. This basal course is commonly given in the freshman year, though sometimes it is deferred to the soph.o.m.ore year. Its content is now fairly uniform in different colleges, the first semester being commonly devoted to general fundamental considerations and the chemistry of the non-metals, while the metals receive attention in the second semester, the elements of qualitative a.n.a.lysis being in some cases taught in connection with the chemistry of the metals.

The work is almost universally conducted by means of lectures, laboratory work, and recitations. The lectures have the purpose to unfold the subject, give general orientation as to the most important fundamental topics and points of view, and furnish impetus, guidance, and inspiration for laboratory study and reading. To this end the lectures should be ill.u.s.trated by means of carefully chosen and well-prepared experiments. These serve not only to ill.u.s.trate typical chemical processes, and fundamental laws, but they also stimulate interest and teach the student many valuable points of manipulation, for it is well-nigh impossible to watch an expert manipulator without absorbing valuable hints on the building up, arranging, and handling of apparatus. In the lectures the material should be presented slowly, carefully, and clearly, so that it may readily be followed by the student. Facts should always be placed in the foreground, and they should be made the basis of the generalization we call laws, and then the latter naturally lead to theoretical conceptions. It is a great mistake to begin with the atomic theory practically the first day and try to bolster up that theory with facts later on as concrete cases of chemical action are studied. On the other hand, it is also quite unwise to defer the introduction of theoretical conceptions too long, for the atomic theory is a great aid in making rapid progress in the study of chemistry. At least two or three weeks are well spent in studying fundamental chemical reactions as facts quite independent of any theories whatsoever, in order that the student may thoroughly appreciate the nature of chemical change and become familiar with enough characteristic and typical cases of chemical action so that the general laws of chemical combination by weight and by volume may be logically deduced and the atomic and molecular theories presented as based upon those laws.

Up to this stage the reactions should be written out in words and all formulation should be avoided, so that the student will not get the idea that "chemistry is the science of signs and symbols," or that "chemistry is a hypothetical science," but that he will feel that chemistry deals with certain very definite, characteristic, and fundamental changes of matter in which new substances are formed, and that these processes always go on in accordance with fixed and invariable laws, though they are influenced by conditions of temperature, pressure, light, electricity, and the presence of other substances in larger or smaller amounts. The theory and formulation when properly introduced should be an aid to the student, leading him to see that the expression of chemical facts is simplified thereby.

Thus he will never make the error of regarding the symbol as the fundamental thing, but he will from the very outset look upon it simply as a useful form of shorthand expression, as it were, which is also a great aid in chemical thinking. Facts and theories should ever be kept distinct and separate in the student's mind, if he is to make real progress in the science.

A thoroughgoing, logical presentation of the subject, leading the student slowly and with a sense of perfect comprehension into the deeper and more difficult phases, should const.i.tute one of the prime features of the work of the first year. Interest should constantly be stimulated by references to the historical development of the subject, to the practical applications in the arts and industries, to sanitation and the treatment of disease, to the providing of proper food, clothing, fuel, and shelter, to the problems of transportation and communication, to the chemical changes that are constantly going on in the atmosphere, the waters, and the crust of the earth as well as in all living beings. Nevertheless, all the time the _science_ should be taught as the backbone of the entire course. The allusions to history and the manifold applications to daily life are indeed very important, but they must never obscure the science itself, for only thus can a thorough comprehension of chemistry be imparted and the benefits of the mental drill and culture be vouchsafed to the student.

=Methods of teaching--The Lecture method=

For the freshman and soph.o.m.ore, two lectures per week are sufficient for this type of instruction. In these exercises the student should give his undivided attention to what is presented by the lecturer. The taking of notes is to be discouraged rather than encouraged, for it results in dividing the attention between what is presented and the mechanical work of writing. To take the place of the usual lecture notes, students of this grade had better be provided with a suitable text, definite chapters in which are a.s.signed for reading in connection with each lecture. The text thus serves for purposes of review, and also as a means for inculcating additional details which cannot to advantage be presented in a lecture, but are best studied at home by perusing a book, the contents of which have been illuminated by the experimental demonstrations, the explanations on the blackboard, the charts, lantern slides, and above all the living development and presentation of the subject by the lecturer. The lectures should in no case be conducted primarily as an exercise in dictation and note taking. If the lectures do not give general orientation, illumination, and inspiration for further study in laboratory and library, they are an absolute failure and had better be omitted entirely. On the other hand, when properly conducted the lectures are the very life of the course.

=The laboratory work=

The laboratory work should be well correlated with the lectures, especially during the first year. The experiments to be performed by the student should be carefully chosen and should not be a mere repet.i.tion of the lecture demonstrations. The laboratory experiments should be both qualitative and quant.i.tative in character. They should on the one hand ill.u.s.trate the peculiar properties of the substances studied and the typical concomitant changes of chemical action, but on the other hand a sufficient number of quant.i.tative exercises in the laboratory should be introduced to bring home to the student the laws of combining weights and volumes, thus giving him the idea that chemistry is exact and that quant.i.tative relations always obtain when chemical action takes place. At the same time the quant.i.tative exercises lay the basis for the proper comprehension of the laws of combining weights and volumes and the atomic and molecular theories.

At least three periods of two consecutive hours each should be spent in the laboratory per week, and the laboratory exercises should be made so interesting and instructive that the student will feel inclined to work in the laboratory at odd times in addition if his program of other studies permits. The laboratory should at all times be, as its name implies, a place where work is done. Order and neatness should always prevail. Apparatus should be kept neat and clean, and in no case should slovenly habits of setting up apparatus be tolerated. The early introduction of a certain amount of quant.i.tative experimentation in the course makes for habits of order and neatness in experimentation and guards against bringing up "sloppy" chemists.

=The student's laboratory record=

The laboratory notebook should be a neat and accurate record of the work in the laboratory. To this end the entries in the notebook should be made in the laboratory at the time when the experiment is actually being performed. The writing of data on loose scratch paper and then finally writing up the notebook later at home from such sheets is not to be recommended, for while thus the final appearance of the notebook may be improved, it is no longer a first-hand record such as every scientist makes, but rather a transcribed one. The student, in making up such a transcription, is only too apt to draw upon his inner consciousness to make the book appear better; indeed, when he has neglected to transcribe his notes for several days, he is bound to produce anything but a true and accurate record, to say nothing about being put to the temptation to "fake" results which he has either not at all obtained in the laboratory, or has recorded so imperfectly on the scratch paper that he can no longer interpret his record properly.

The only true way is to have the notes made directly in the permanently bound notebook at the time when the experiment is actually in progress. The student ought not to take the laboratory notebook home at all without the instructor's knowledge and permission. Each experiment should be entered in the notebook in a brief, businesslike manner. Long-winded, superfluous discussions should be avoided. As a rule, drawings of apparatus in the notes are unnecessary, it being sufficient to indicate that the apparatus was set up according to Figure so-and-so in the laboratory manual or according to the directions given on page so-and-so. The student should be made to feel that the laboratory is the place where careful, purposeful experimentation is to be done, that this is the main object of the laboratory work, and that the notebook is merely a reliable record of what has been accomplished. To this end the data in the notebook should be complete, yet brief and to the point, so that what has been done can be looked up again and that the instructor may know that the experiment has been performed properly, that its purpose was understood by the student, and that he has made correct observations and drawn logical conclusions therefrom. While in each case the notes should indicate the purpose of the experiment, what has actually been done and observed, and the final conclusions, it is on the whole best not to have a general cut-and-dried formula according to which each and every experiment is to be recorded. It is better to encourage a certain degree of individuality in this matter on the part of each student. Notebooks should be corrected by the teacher every week, and the student should be asked to correct all errors which the teacher has indicated. A businesslike atmosphere should prevail in the laboratory at all times, and this should be reflected in the notebooks. Anything that savors of the pedantic is to be strictly avoided. Small blackboards should be conveniently placed in the laboratory so that the instructor may use them in explaining any points that may arise. Usually the same question arises with several members of the cla.s.s, and a few moments of explanation before the blackboard enable the instructor to clear up the points raised. This not only saves the instructor's time, but it also stimulates interest in the laboratory when explanations are thus given to small groups just when the question is hot.

It is, of course, a.s.sumed that the necessary amount of apparatus, chemicals, and other supplies is available, and that the laboratory desks, proper ventilation of the rooms, and safeguards in the case of all experiments fraught with danger have received the necessary painstaking attention on the part of the instructor, who must never for a moment relax in looking after these matters, which it is not the purpose to discuss here. At all times the student should work intelligently and be fully aware of any dangers that are inherent in what he is doing. It need hardly be said that a beginner should not be set at experiments that are specially dangerous. Having been given proper directions, the student should be taught to go ahead with confidence, for working in constant trepidation that an accident may occur often creates a nervous state that brings about the accident.

Too much emphasis cannot be laid upon proper, definite laboratory instructions, especially as to kinds and amounts of materials to be used. Such directions as "take a _little_ phosphorus," for example, should be strictly avoided, for the direction as to amount is absolutely indefinite and may in the case where phosphorus or any other dangerous substance is used lead to dire accidents. The student should be given proper and very definite directions, and then he should be taught to follow these absolutely and not use more of the materials than is specified, as the beginner is so apt to do, thus often wasting his time and the reagents as well. Economy and the correct use of all laboratory supplies should be inculcated indirectly all the time. A fixed set of printed rules for the laboratory is generally neither necessary nor desirable when students are properly directed to work intelligently as they go, and good directions are given in the laboratory manual. Thus a spirit of doing intelligently what is right and proper, guarding against accidents, economizing in time and materials of all kinds will soon become dominant in the laboratory and will greatly add to the efficiency of the workers.

Minor accidents are almost bound to occur at times in spite of all precautions, and the instructor should be ready to cope with these promptly by means of a properly supplied first-aid kit.

=Recitations and quizzes=

For students of the first year quizzes or recitations should be held at least twice a week. In these exercises the ground covered in the lectures and laboratory work should be carefully and systematically reviewed. The quiz cla.s.ses should not be too large. Twenty-five students is the upper limit for a quiz section. The laboratory sections too should not be larger than this, and it is highly desirable that the same instructor conduct both the recitation and the immediate laboratory supervision of the student. Lecture cla.s.ses can, of course, be very much larger in number. In most colleges the attendance upon cla.s.ses in chemistry is so large that it is not possible for the professor to deliver the lectures and also personally conduct all of the laboratory work and recitations. It is consequently necessary to divide the cla.s.s up into small sections for laboratory and quiz purposes. It is highly desirable that the student become well acquainted with his individual instructor in laboratory and quiz work, and therefore it would be unfortunate to have one instructor in the laboratory and still another instructor in the quiz. It might be argued that it is a good thing to have the student become acquainted with a number of instructors, but in the writer's experience such practice results to the disadvantage of the student, and is consequently not to be recommended.

In the recitations the student is to be encouraged to do the talking.

He is to be given an opportunity to ask questions as well as to answer the queries put by the teacher. Short written exercises of about ten minutes' duration can be given to advantage in each of these recitations. In this way the entire cla.s.s writes upon a well-chosen question or solves a numerical chemical problem and thus a great deal of time is saved. The quiz room should be well provided with blackboards which may be used to great advantage in the writing of equations and the solution of chemical problems just as in a cla.s.s in mathematics. The textbook, from which readings are a.s.signed to the student in connection with the lectures, should contain questions which recapitulate the contents of each chapter. When such questions are not contained in the book, they ought to be provided by the teacher on printed or mimeographed sheets. When properly conducted, the recitation aids greatly in clarifying, arranging and fixing the important points of the course in the mind of the student. Young instructors are apt to make the mistake of doing too much talking in the quiz, instead of encouraging the student to express his views. In these days, when foreign languages and mathematics are more or less on the wane in colleges, the proper study of chemistry, particularly in the well-conducted quiz, will go far toward supplying the mental drill which the older subjects have always afforded.

=Summary of first-year course=

If the work of the first year has been properly conducted, it will have given the student a general view of the whole field of chemistry, together with a sufficient amount of detail so securely anch.o.r.ed in careful laboratory work and practical experience as to form a basis for either more advanced work in chemical lines or in the pursuance of the vocations already mentioned in which a knowledge of chemistry is basal. It is hardly necessary to add that if well taught, the student will at the end of such a course have a desire for more chemistry.

=Organization of second-year course=

The work of the second year of chemistry in college generally consists of quant.i.tative a.n.a.lysis, though the more intensive study of the compounds of carbon, known as organic chemistry, is also frequently taken up at this time, and there is much to be said in favor of such practice.

=Content of the course in quant.i.tative a.n.a.lysis=

In the quant.i.tative a.n.a.lysis, habits of neatness and accuracy must be insisted upon. It is well to give the general orientation and directions by means of lectures. One or two such exercises per week will suffice. There should also be recitations. When two lectures per week are given, it will suffice to review the work with the student in connection with such lectures, provided the cla.s.s is not too large for quiz purposes. Intelligent work should characterize a course in quant.i.tative a.n.a.lysis. To this end the student should be taught how to take proper representative samples of the material to be a.n.a.lyzed. He should then be taught how to weigh or measure out that sample with proper care. The manipulations of the a.n.a.lytical process should be carried out so that each step is properly understood and its relations to the general laws of chemistry are constantly before the mind. In carrying out the process, the various sources of error must be thoroughly appreciated and guarded against. The final weighing or measuring of the form in which the ingredient sought is estimated should again be carried out with care, and in the calculation of the percentage content due regard should be had for the limits of error of experimentation throughout the entire a.n.a.lytical process. The student feels that a large number of the exercises in quant.i.tative a.n.a.lysis are virtually cases of making chemical preparations of the highest possible purity, thus connecting his previous chemical experience with his quant.i.tative work. The course in quant.i.tative a.n.a.lysis should cover the determination of the more important basic and acid radicals, and should consist of both gravimetric and volumetric exercises.

The choice of the exercises is of great importance. It may vary, and should vary considerably in different cases. Thus a student in agriculture is naturally interested in the methods of estimating lime, phosphorus, nitrogen, potash, silica, sulphur, etc., whereas a student in engineering would be more interested in work with the heavy metals and the ingredients which the commercial samples of such metals are apt to contain. Thus, a.n.a.lytical work on solder, bearing metal, iron and steel, cement, etc., should be introduced as soon as the student in engineering is ready for it. It is quite possible to inculcate the principles of quant.i.tative a.n.a.lysis by selecting exercises in which the individual student is interested, though, to be sure, certain fundamental things would naturally have to be taken by all students, whatever be the line for which they are training. A few exercises in gas a.n.a.lysis and also water a.n.a.lysis should be given in every good course in quant.i.tative a.n.a.lysis that occupies an entire year. Careful attention should be given to the notebook in the quant.i.tative work, and the student should also be made to feel that in modern quant.i.tative a.n.a.lysis not only balances and burettes are to serve as the measuring instruments, but that the polariscope and the refractometer also are very important, and that at times still other physical instruments like the spectroscope, the electrometer, and the viscometer may prove very useful indeed.

The quant.i.tative a.n.a.lysis offers a splendid opportunity for bringing home to the student what he has learned in the work of the first year, showing him one phase of the application of that knowledge and making him feel, as it were, the quant.i.tative side of science. This latter view can be imparted only to a limited degree in the first year's work, but the quant.i.tative course offers an unusual opportunity for giving the student an application of the fundamental quant.i.tative laws which govern all chemical processes. It is not possible to a.n.a.lyze very many substances during any college course in quant.i.tative a.n.a.lysis. The wise teacher will choose the substances to be a.n.a.lyzed so as to keep up the interest of the student and yet at the same time give him examples of all the fundamental cases that are commonly met in the practice of a.n.a.lytical work. A careful, painstaking, intelligent worker should be the result of the course in quant.i.tative a.n.a.lysis. Toward the end of the course, too, a certain amount of speed should be insisted upon. The student should be taught to carry on several processes at the same time, but care should be taken not to overdo this.

=The course in organic chemistry=

In the course in organic chemistry, lectures, laboratory work, and recitations, arranged very much as to time as in the first year, will be found advantageous. If the intensive work in organic chemistry is postponed to the third year in college, there are certain advantages.

For example, the student is more mature and has had drill and experience in the somewhat simpler processes commonly taught in general and a.n.a.lytical chemistry. On the other hand, the postponing of organic chemistry to the third year has the disadvantage that the student goes through his basal training in quant.i.tative a.n.a.lysis without the help of that larger horizon which can come to him only through the study of the methods of organic chemistry. The general work of the first year, to be sure, if well done compensates in part for what is lost by postponing organic chemistry till the third year, but it can never entirely remove the loss to the student. Teachers will differ as to whether the time-honored division of organic chemistry into the aliphatic and aromatic series should be maintained pedagogically, but they will doubtless all agree that the methods of working out the structure of the chemical compound are peculiarly characteristic of the study of the compounds of carbon, and these methods must consequently const.i.tute an important point to be inculcated in organic chemistry. The derivation of the various types of organic compounds from the fundamental hydrocarbons as well as from one another, and the characteristic reactions of each of these fundamental forms which lead to their identification and also often serve as a means of their purification, should naturally be taught in a thoroughgoing manner. The numerous practical applications which the teacher of organic chemistry has at his command will always serve to make this subject one of the deepest interest, if not the most fascinating portion of the entire subject of chemistry. No student should leave the course in organic chemistry without feeling the beautiful unity and logical relations.h.i.+p which obtains in the case of the compounds of carbon, the experimental study of which has cast so much light upon the chemical processes in living plants and animals, processes upon which life itself depends. The a.n.a.lysis of organic compounds is probably best taught in connection with the course in organic chemistry. It is here that the student is introduced to the use of the combustion furnace and the method of working out the empirical formulae of the compounds which he has carefully prepared and purified. The laboratory practice in organic chemistry generally requires the use of larger pieces of apparatus. Some of the experiments also are connected with peculiar dangers of their own.

These facts require that the student should not approach the course without sufficient preliminary training. Furthermore, the teacher needs to exercise special care in supervising the laboratory work so as to guard the student against serious accidents.

The historical development of organic chemistry is especially interesting, and allusions to the history of the important discoveries and developments of ideas in organic chemistry should be used to stimulate interest and so enhance the value of the work of the student. The practical side of organic chemistry should never be lost sight of for a moment, and under no condition should the course be allowed to deteriorate into one of mere picturing of structural formulae on the blackboard. All chemical formulas are merely compact forms of expression of what we know about chemical compounds. There are, no doubt, many facts about chemical compounds which their accepted formulas do not express at all, and the wise teacher should lead the student to see this. There is peculiar danger in the course in organic chemistry that the pupil become a mere formula wors.h.i.+per, and this must carefully be guarded against.

The applications of organic chemistry to the arts and industries, but especially to biochemistry, will no doubt interest many members of the cla.s.s of a course in organic chemistry if the subject is properly taught. This will be particularly the case if the teacher always holds before the mind of the pupil the actual realities in the laboratory and in nature, using formulation merely as the expression of our knowledge and not as an end in itself.