APPLICABILITY of the LECTURE DEMONSTRATION METHOD to CERTAIN GROUPS of STUDENTS* ALBERT L. ELDER Syncuse University, Syracuse, New York
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IFFERENCES of opinion in science are dispelled The answers most frequently listed for the first quesas soon as sufficient scientific data have been tion were: (1) Professors of education, (2) College obtained. I need not recall any of the long administrators, and (3) Economic conditions. list of chemical theories which have been discarded, In answer to the question, "Do yon believe in this as further studies clarified the points in questiou. method of teaching chemistry?" 16% replied Yes, and Laboratory investigations are not the mere accumula- 84%, No. tion of data. There are several specific steps in orderly Such comments as the following express the opinions research. of both sides: 1. Can a statement of the problem be made? No; each chemical problem is an individual case and must be 2. Can any data be obtained? This takes the treated as such. The student realizes this only when in actual question out of the stage of opinions based on opinions. contact with the experiment. every dzrdent shodd hahave some training i n the technic of 3. Can the experimental variables be so controlled s oNo; w experimental science end i n the scientific method. The mowsthat the data are reasonably reliable, and are the data ment probably comes from men who hevc h d no genuine scientific sufficient to average out the inherent experimental training. No; does not train a student t o do a thing himself, obseme, errors? draw conclusions from his own obsemations. 4. Can the experiments be repeated by others, and No. I believe that students learn more by actually doing a thus eliminating the personal equation? thing than by seeing it done no matter how far superior t o their efforts the demonstration may be. However, we should, I think, Whenever possible, differences of opinion should be cut down on the amount of laboratory work required in general subjected to the rigorous treatment of scientific re- chemistry and emphasize more the type of work and the undersearch. Many of our differences of opinion are the standing of what the student is doing. Rather than sacrifice result of our inability to submit the point in questiou to laboratory training, I believe in graduate students' teaching. Yes; such a very small percentage of beginning students follow the scientific method. chemistry; those who do not, lose the laboratory knack and Those of us participating in this symposium on lec- up knowledge gained in laboratory very quickly. Specializing ture demonstration as. laboratory instruction have been students can make up the very necessary laboratory work later. warned [Editorial, J. CHEM.EDUC., 12, 152 (April, Yes; expensive laboratary work for the mass of credit-hunters 1935)l of some of the pitfalls which we should try is a waste of good public funds. Of course we would not give the demonstration-lecture courses alone to the real chemistry and to avoid in our discussions. medical students. That there exists a definite difference of opinion concerning the merits of the lecture demonstration as. the Even though everyone answering the questionnaire laboratory method of teaching chemistry is shown by had favored one method or the other, i t would not the numerous published papers on this subject. Last necessarily follow that the method favored is better. December, I conducted an experiment on opinions by The only merit which this questionnaire study had was the questionnaire method--one hundred question- that of focusing attention on the existing difference of naires were evenly distributed among college chemistry opinion and thereby suggestmg the need for further exteachers and industrial chemists. Among the ques- perimentation. It appears plausible to assume that tions were the following: the opinions which we have are based on some evidence. "There appears to be a tendency among some of our We must now resubmit our evidence to the same rigorcolleges and universities to introduce lecture-demon- ous treatment that we would apply to any other worthstration courses in beginning chemistry with the elimi- while data. nation of laboratory work by the student. Whom do Part of the confusion concerning the merits and the you consider most responsible for this change? Do applicability of these two methods of teaching rests in a you believe in this method of teaching chemistry?" failure to state the problem clearly-in what way or ways is one method superior to the other? Some * Contribution t o the symposium on Lecture Demonstration have measured superiority in terms of cost of plant Method vs. Individual Laboratory Work conducted by the Division of Chemical Education a t the eighty-ninth meeting of the equipment, the size of teaching st&, immediate student interest, manipulative skill, written examinaAmerican Chemical Society, New York, April 25, 1935. 65
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tions, et cetera. Clearly, first and foremost in importance must be a statement of the objectives of the laboratory method. Secondly, we must consider whether or not these objectives all fall within those of the first course in general chemistry. All teachers of general chemistry will profit by reading "Accepted objectives in the teaching of general college chemistry," by Otto M. Smith [J. CHEM. E ~ u c . ,12, 180-2 (1935)l. One might expect to find the objectives of the laboratory method expressed in introductions to laboratory manuals of chemistry. As a rule such communications to the students are conspicuously lacking. Preceding Experiment I there is usually a list of the experiments which may be omitted and a summary of what to do in case of accident. Such an introduction might be construed as an argument for the demonstration method. What are the objectives of the laboratory method? Obviously, all these objectives must be found among the more general objectives previously mentioned. Some of the objectives we would probably all agree upon, e. g., the objectives of Professor Scblesinger :' to see, to think, and to do. In the clarification of ideas on these or other objectives in the teaching of chemistry, one will find the book of E. R. Downing, "An introduction to the Teaching of Science," University of Chicago Press, 1934, helpful. Once we have clearly stated the objectives of the laboratory method, we are in a position to attempt a comparative evaluation of the demonstration method in terms of those objectives. In these days of forced leisure i t may be that we are giving too much weight to the time factor in learning. Also, until it can be proved that one method is clearly superior to the other in satisfying the objectives of the course, cost factors should not be used as a basis for comparison. Colleges and universities will not, in the final analysis, stand or fall on the cost of education, but on their degree of success in attaining their objectives. As teachers in colleges and universities, i t is not our goal to see how cheap, but how good a product we can produce-the mere granting of a degree may not be evidence of an education. If the two primary objectives to be compared are cost and the speed with which material may be processed, then i t is granted that the lecture-demonstration method is superior. TESTING THE ATTAINMENT OF THE OBJECTIVES
Having stated the objectives of the laboratory method of teaching, it is necessary to conduct the laboratory periods so that these goals may be best attained. Much of our difference of opinion concerning the applicability of these methods rests on the fact that our laboratory work is not so conducted. If one turns to articles in the chemical research journals, one finds in nearly every article the topic "re-
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1 H . I. SCELESINGBR. "The contribution of laboratory work to general education," J. CHEM.Enuc., 12, 524-8 (Nov., 1935).
agents" and a statement to the effect that the reagents were purified in the following manner.. . . The reagents, with which the data on these methods of teaching have been obtained, are human beings, which have been subjected to innumerable methods of pretreatment, and have no constants for absorbability as a function of temperature or pressure, or power of reteution as a function of time. Many attempts have been made to standardize these human errors by grouping the students according to their mental capacities, like interests, et cetera. Our objectives need not be the same for all groups. If the groups differ, then the applicability of the method for presenting the material may not be the same. Full cognizance of the differences in students and objectives is essential. Harry Woodburn Chase, in the American Mercury for November, 1934, states that "the usual elementary courses, for example, in chemistry or biology, are taught as though each beginner were taking his first feeble step toward the Ph.D. They stress laboratory manipulation and technical detail rather than the broad underlying principles of the science as a part of the equipment of the cultured layman." It is di5cult for the scientist to understand how one may teach the broad underlying principles of science and a t the same time omit attention to the laboratory manipulation and the technical detail which were so essential to the development of these broad underlying principles. Is i t possible so to classify chemistry students that the broad underlying principles can be taught to some, and more complete type of training given to others? It is diEcult to find published data on the exact tests used in comparing the applicability of these two methods of teaching. The tests used should be those which actually measure the degree of achievement according to the standards of the laboratory method. Having stated the purpose of the laboratory work, these same tests must then be used by those measuring the results of the demonstration method. I cannot over-emphasize this point. Too often one reads regarding examinations, "the material used was descriptive and the tests factual." All the followers of the demonstration method must be exceedingly careful of the type of test used to measure the degree of attainment. As an example of the one specific type of test which might be used, I wish to call attention to one part of the final examination whicb we used a t Syracuse University a t the end of the first semester this year. The last three laboratory periods were used for this examination whicb was as follows: The following are among the reagents which have been used this semester: Elements-S, Sb, Al, Zn, C; NitratcsNaNO~, NItNOs. AgN08; Oxides-MgO, HgO, CuO, SiO,, 1206, ZuO, PsOr; ChloratesNaCIG; PcroxidcidesBaOn, NanOl, HzO*: CarbonatesCaC08, NarCOs. NaHCOs; Simple Halogen Salts-NaC1, NH,Cl, CoClr(HsO)a, NiSO,(HsO)r, BaCh(HsO)1, CaCIdHaO)s. NaBr. Nal, AICI,, FeCIn, CuBr,; PermnganutesKMnO,;
SulfulcsPbS; Acelate+NaGHaO~(HaO)a; Acids-HCI, HnSO,, many cases to the survey type of course which is often HNOI: Sulja6es-N%SO4(H2O)~ CuSO,, CuS04(H20)~, accused of being a millimeter of physics, a smell of (CaSOSsHxO. CaSO,(H$O).; Phosphates-NaaP04; SugarC12HnOll; Colloid-Fe(0H). As&; Liquidsdistilled H1O, chemistry, a pick of geology, a peek a t astronomy, a leaf of botany, a slice of zoology, and may even include C%. CCL, kerosene, BiClr(aq.); B a s c s N a O H . NH,OH. As part of your final examination you will be given samples of a small proportion in mathematics and possibly a some of these materials t o identify. The number of substances psychic bid or two. From this viewpoint, the problem you examine and report upon will depend on your ability. The stated briefly is, which is better-a blind spot or a blur? last three laboratory periods are allotted to this work. Next fall (1935), Syracuse University inaugurates a 1. Obtain your instructor's signature on one of these sheets, course in the physical sciences and a course in the authorizing the storeroom keeper to give you a sample. 2. Take this slip and a clean, dry test-tube to the storeroom natural sciences. These two courses will satisfy the window. science group requirement. To take care of individual 3. Identify the substance given you. student differences, the student can substitute an equiv4. Report t o the Examining Committee (see notice on the hours in the re@'1ar laboratory bulletin board). If your report is correct, answer the following alent questions and then report again for your oral examination on this in either physics or chemistry; or geology, botany, or material. zoology. In these new courses the lecture demonstra(a) Outline on this sheet the tests used t o identify the tion 211 play an important part. It appears to me material. that the " meatest an~licahilitv of rests-in &~.~ ~ ~ ~- this ~method ~ - ~~ ( 6 ) Answer on this sheet the following questions: courses of this type. (1) What is the position in the periodic table of each of the
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(2) . . Show the electron arrangement of each element in the substance. 13) Show the structural formula of the substance. ?4i List its chemical orooerties. (5) Give equations to illustrate these properties. ( 6 ) If water-soluble. show ions formed. (7) Assuming no ionization, calculate the boiling point of a saturated solution. (8) Is the substance as such found in Nature? If so, where? If not, what is a commercial method for preparing it? (9) Uses? Cost? Use any reference books you desire in answering these questions.
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Let there be no doubt in your minds that this examination consumed a great deal of the time of my teaching st&. But I believe it was worth while. The students thoroughly enjoyed it-they learned chemistry and they benefited by the fulfilment of some of the purposes of laboratory work which I have previously outlined. What could a student trained by the demonstration method do with such an examination?
In the questionnaire already mentioned, this auestion was -asked: "DO you -believe if a stud& is to take only one course in the physical sciences that, on the average, it will be more valuable for the student to take one course in one science than a composite course, for example, in astronomy, chemistry, and physics?" Forty-seven per cent. of the replies said Yes and 53% said No. Some of the comments added are interesting: No; a single course in science should be built around a few broad generalizations of science, the mastery of which will enable the layman t o appreciate science and scientists. No; a student not majoring in science should take a composite course, the so-called general science course. Yes; if he can take but one science, let him concentrate on one rather than portions of several. Yes; there is a defmite place for a survey course in high school. not in college.
These students come to our chemistry classes in most cases because a science is required. They have chosen chemistry as the lesser of two evils (usually the choice is physics or chemistry). They have an abhorrence for the smells of the lahoratory, a fear of the popping of INDIVIDUAL DIFFERENCES hydrogen, and a dislike for washing test-tubes. If It has often been said that one of the favorite pastimes one studies their cases carefully, i t will usually be found of college faculties is participation in curricular changes. that their blind spot is the lack of ability to do anyNearlv everv institution is boastinz of its chanees to thing for themselves which calls for persistence, acmeet lhe neidds of the students. ~ h & is e meal jugifica- curacy, and organization. The changing cumculum is tion for this state of flux of our college curricula. evidence that our present courses are not adaptable to An ever-increasing heterogeneity of student body, these students. If they are taught by the demonstradifferences in previous training, and diversity of student tion method they can a t least see science in action. interests all tend to make the stereotyped course less The cultural value of science will be emphasized. adaptable to the present day. Whether or not the students have more than a blur a t The training in fundamentals, mathematics, for ex- the conclusion of such courses will depend upon the ample, is becoming less and less. This general factor teachers, their objectives, and standards of achievemakes it more difficult for the mediocre student to ment. To some it appears better that we realize that satisfy the high standards set by the science faculties. we are dealing with an inferior type of science student Economic conditions now make it necessary to salvage and give them that which they are capable of mastering, rather than attempt to force them beyond their these students if possible. One school of thought holds that our elementary capacities. Much of our whole educational program, within and science courses are not suited to the students seeking only a cultural training in the sciences. This has led in without schools, tends to educate by methods which
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make no provision for "doing." Unless a t the same time we a t least give the student an opportunity to learn by doing, our practice may be the curse of future generations. May I offer the plea that we give the student an opportunity for individual expression of preference as to the type of training he is to receive and that if he wants to work in the laboratory, he may be permitted to do so? Never in the history of this nation has there been greater need for power of individual observation and critical analysis. Having dealt with the poor student, we must consider the good students and the students interested in science. Scientific technic comes from experiencethere is a de6nite carry-over from one field of science to another. The laboratory offersthe best opportunity for individual expression of these students and i t is here that we can truly accommodate individual differences among students. I n the second semester of the 1933-34 school year, we segregated our "A" students and then carried out fow experiments by the demonstration method, four experiments with students working in groups of four, and four experiments with students working in pairs, and then asked the students how they wanted the laboratory operated for the rest of the time. They were almost unanimously in favor of the individual labora-
tory method which they had used during the first semester, as this method gave them the most freedom for individual work. CONCLUSIONS
In view of the hancial pressure upon schools a t the present time, i t is advisable that these experiments be extended until they prove to the satisfaction of the college and school administrators and teachers the relative merits of the lecture-demonstration and the laboratory method. These experiments must follow the orderly course of any other scientific investigation. We need to have clearly in mind the objectives of general chemistry and the objectives of the laboratory method. Examinations must test the degree of achievement of these objectives. The lecture-demonstration method is most applicable to students whose major interests are not in the sciences. A middle ground upon which teachers can stand is to offer both types of courses. The results of years of experience will serve as the true guide and justification for the survival of the fittest. The student would a t the same time be assuming the responsibility for the type of science training he is to receive, which places the responsibility where it belongs in college education.
