An Introduction to Chemical Gene G. Wubbels
Grinnell College Grinnell, Iowa 50112
Literature through Examination A new approach at an intermediate level
A
traditional and important function of undergraduate chemistry curricula is to introduce students to the original literature of the discipline. This is often accomplished by a special course or seminar taken during t,he junior or senior year or by an adjunct to an advanced course or laboratory. We have found it both feasible and desirable to begin literature work at an earlier point in the curriculum, namely the sophomore-level organic chemistry course. In this article we describe an examination approach to introducing students to the chemical periodical literature which has proved effective in use over a three-year period at Grinnell. The introductory organic chemistry course at Grinnell consists of two semesters with a format of three hours of lecture and one three-hour laboratory per week. All students enrolled (40-50) have completed two semesters of introductory chemistry; about half are pre-medical students and from 15 to 20 are potential chemist,ry majors. The text by Morrison and Boyd has been used in recent years. The literature examinat,ion is assigned about five weeks prior to the cnd of the second semester classes and is due four weeks later. The exercise requires approximately 20-30 hr of work and applies toward st,udcnts' grades. During the period of work on the examination, class assignments are reduced somewhat,. Each examination is a unique set of three questions selected to correspond to t,he individual interests of
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students. An interest questionnaire completed by students prior to the examination is the basis for the assignment of questions. While the match of student interests with questions is only approximate, the students appreciate the attempt to accommodate their interests. Each examination question is based on a particular article or closely related series of articles from major English language journals. The primary criterion for selection of an article is whether the student can be expected to understand the content, after a reasonable amount of work, with little reliance on secondary sources. The second criterion is whether the article has a special attribute such as relevance to an item of general student interest (living systems, drugs, environment, etc.), obvious representation of one side of a dispute or one step in the development of an idea, or contribution of new evidence concerning an important model in organic chemistry with which the student is familiar. The subject matter of the articles chosen included synthesis, physical organic chemistry, mechanistic studies, and structure proofs; much of it was directly relatable to biological systems. A pool of fifty-five questions was made for a section of about 20 students. About one-third of the questions were based on reports found in a random survey of over 100 articles. Another third of the questions were drawn from personal recollections and the remainder nere selected from review
literature. For grading purposes short answers emphasizing experiments and data were recorded when the questions were made up. The following example is representative of a mechanistic question. The von Richter reaction has been shown to be a fairly general reaction of nitrohenzenes. NO,
Several studies of the reaction mechanism have been reported. (a) What was the reaction mechanismreportedin 1956? ( b ) What were the experimental bases for each aspect of the mechanism?
For each question the student objectives are fivefold: (1) to locate the primary article using the information in the questions; (2) to understand the article and answers to the specific questions using secondary resources as necessary; (3) to locate a second paper appearing in the literature subsequent to the first paper dealing with an important aspect of the first paper; (4) to comprehend the second article and its relationship to the first article; (5) to write answers to the questions posed originally including a discussion of pertinent points raised by the second article. Several guidelines were issued for pursuing answers. Students were given an hour lecture on characteristics and use of the periodical literature with emphasis on Chemical Abstracts. A list of chemical journals held by the College library was supplied along with a brief characterization of each; the utility of year-end journal indexes was noted. A listing of reference books in the class textbook was also mentioned. Students were encouraged to consult with the instructor whenever an impasse was reached, and to confirm primary references with the instructor before proceeding. The criterion of completeness or detail used in the answers was that which, in the studat's judgment, appeared adequate for a critical understanding of the answer. The length of the answers varied considerably from two to ten typewritten pages. No qualifications were placed on authors of the primary article being (or not being) authors of the second paper. However students were asked to seek followup papers which threw new light on the original findings and to focus discussion on points of disagreement or independent confirmation of findings. They were encouraged to interpret liberally the statement, ". . .dealing with an important aspect of thc first paper." It was noted that the success of their search would depend in part on their ability to conceptualize the original workin terms of key words or models. As an example, the question dealing with the von Richter reaction generally leads first to the series of three articles by Bunnett and Rauhut.' Following this rather complete introduction to the problem, the student will probably find, using obvious key-words, two pertinent studies reported in 1960.2 The oxygen labeling experiment of Samuel furnishes confirmation for a central feat,ure of the Bunnett mechanism, while the results of the nitrogen labeling experiment of
Rosenblum require important modifications in that mechanism. The student must study the respective experimental results closely in order to rationalize the differing conclusions. Grading of the examination papers is somewhat problematical. With brief notes on the experimental results of individual primary references, one must judge the student reports largely on whether the appropriate details and emphases have been included. Attention to internal consistency, aptness of expression, and the relationship between conclusions and experimental findings are of primary importance in the exercise. These qualities or the absence of them are readily a p parent in the papers. Occasionally one must consult the original articles when student representations are unclear. About 1-2 hr are required to grade each examination. Student response to the exercise has been very positive. Over 75% of the claas during the first year the examination was given gave it an "excellent" or "good" rating on a course evaluation questionnaire. Many students seemed elated by the finding that the original literature was both accessible and interesting to them. The fact that the examinations were directed toward individual student interests undoubtedly accounts in part for the satisfaction expressed by the biology majors and pre-medical students. Regarding style of pedagogy the examination has some of the characteristics of the transfer retention test described by AusubeL8 I n Ausubel's terms the transfer retention test measures ''. . . the extent to which retained knowledge of subject matter is sufficiently stable and well-organized to he available as a foundation for learning new, sequentially dependent material. . ." I n this instance the emphasis is on use of the examination as a learning rather than evaluative device. Thus, through original literature that the student can understand and finds interesting, he apprehends several matters of pedagogical value: the general layout of the chemical literature, the nature and approachability of original research publications, and the pattern of development of models including relationships between results and interpretations. Since the approach described may be adapted t o many different subjects, it could be used in courses primarily devoted to disciplinary topics or in courses or seminars devoted to use of the literature. Some may argue that the sophomore-level organic course is already too full of important content to allow the addition of a literature component. However, we feel that the benefits of a literature component warrant displacement of some of the other "important" material. The benefits include possibilities of closer relationships of advanced courses to original literature, and better student preparation for independent projects or research efforts.
' BUNNETT, J. F., AND RAUHUT, M. M., J. Org. Chem., 21,934, 939, 944 (1956). *SAMUEL, D., J. Chem. Soc., 1318 (1960). J . Amer. Chem. Soc., 82, 3796 (1960).
ROSENBLUM, M.,
'AUBUBEL, D. P., "Education~lP~sychology: A Cognitive View,'' Holt, Rinebart, and Winston, New York, 1968, p. 577; AUSUBEL, D. P., AND FITZGERALD, D., J. E d u ~ . PsYc~oL.,53, 243 (1962). Volume 49, Number 7, July 1972
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