Research: Science and Education edited by
Curricular Change Digests
Baird W. Lloyd Miami University Middletown Middletown, OH 45042
Gradualism: A Method for Primary Instruction on Spectroscopic Analysis in Introductory Organic Chemistry
W
Christopher W. Alexander, Gary L. Asleson, Charles F. Beam, Marion T. Doig, Frederick J. Heldrich,* and Shannon Studer-Martinez Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424; *
[email protected] A common problem faces instructors of introductory organic chemistry. How should we teach spectroscopic characterization? Most of the standard lecture and laboratory texts for the full year-long introductory course include chapters on NMR and IR with varying degrees of coverage devoted to UV–vis or MS. In addition, many laboratory texts include spectroscopy as a product characterization tool for individual experiments. Clearly, spectral characterization has become a standard part of the introductory organic curriculum. It is less clear where and how spectroscopic analysis should be presented to the students in the course. In this report, we describe our development of a method of instruction called gradualism. Variations of this teaching style are used as the primary teaching method by about 25% of the faculty of American Chemical Society certified chemistry programs (1). Surprisingly, application of this method to spectroscopy instruction has not been previously described. Method Description Gradualism is used to describe the application of “structured learning” to spectroscopic analysis in the laboratory. Gradualism is a series of steps or lessons that build one upon the other until the student is able to solve complex problems. Each step is briefly described as part of a pre-laboratory spectroscopy lesson. The pedagogical goal for each step should be well defined and easily mastered, and student learning should be reinforced by application of knowledge as often as possible. In each step, the student gains both a new skill and repeated use of analytic skills acquired from earlier steps. With the final step, the student should be able to apply the knowledge in an integrated manner. As described above, gradualism has some similarity to the “learning cycle” techniques recently described by Libby for introductory organic lectures (2). A major enabling factor for our development of gradualism was the availability of autosampling instrumentation for the analysis of large numbers of student samples (3). We have found that student interest in developing spectroscopic analysis skills as part of the laboratory course is much enhanced when the analysis of proprietary samples is involved. In planning the curriculum, the gradualistic lessons must be reasonable (in terms of student workload), complement the chemical development of the concurrent lecture, and fit the “wet” experiment being performed. Each lesson defines and states discrete spectroscopic goals, providing short explanations with a few worked applications and references to pages from the lecture text where students can read supporting material. We have also prepared a series of computer tutorial
lessons to assist visual learners. We reinforce the laboratory instruction in lecture with brief references to spectral analysis as related to functional groups. A key element of gradualism is one-on-one discussions. These discussions are initiated by the students as they struggle to grasp a skill or as they attempt to apply a skill to data obtained from their experiment. Students with similar, but still distinct, experimental spectral data debate their data and the lessons. We have observed that students who are more actively engaged in discussions of their spectra appear to attain better understanding and long-term retention of the spectroscopic goal. Ultimately, we require students to submit their evaluations and/or predictions of spectral data using the current and all previous goals as part of their laboratory reports for the experiments. This forces them to consolidate and apply the lessons. Snippets of each technique are introduced throughout the year-long course. Techniques are added to complement the intellectual development of the concurrent lecture course. The details of the curricular development can be found in JCE Online.W In general, IR, MS, and 13C NMR are mixed into the first semester curriculum and UV–vis, 1H NMR, and 2D-NMR are presented in the second semester. Obviously, we do not expect our beginning students to become expert spectroscopists. However, we do want them to be knowledgeable beginners, adequately prepared for advanced study. Assessment and Effectiveness We constructed a multiple-choice test of analytical skills and fundamental spectroscopic facts, which was first given to students taught in the old lecture style and then to students in the next 4 cycles of the year-long course, as we phased in the gradualism method. The test had sections on individual areas of spectroscopy and a section on interpretation of multiple spectra. Student performance on this examination remained essentially unchanged. The fact that scores did not decline from what we already felt was an acceptable level was significant. For those who are interested, greater details on the assessment results for gradualism are available in the extended Web version of this article.W While gradualism may not be superior to the lecture style in terms of student learning, it does offer several advantages. Time is liberated from the lecture and/or the laboratory for other essential objectives. Spectroscopy can be incorporated into “wet” laboratories, avoiding the replacement of “wet” laboratory experiences with lectures on spectroscopy. Gradualism is, above all else, an interactive learning process.
JChemEd.chem.wisc.edu • Vol. 76 No. 9 September 1999 • Journal of Chemical Education
1297
Research: Science and Education
It encourages, and can be designed to demand, student independence in the learning process. However, the development of student independence requires significant active participation by the faculty to provide feedback, discussion, encouragement, and goal setting so that students know what to learn and if they have, in fact, learned it. We have found gradualism to be a viable alternative to more traditional means of spectroscopic instruction. Acknowledgments We want to thank Andrew Peery, a student who experienced the curriculum described, for his thoughtful review of the manuscript. Partial support for this work was provided by the National Science Foundation’s Division of Under-
1298
graduate Research through grants DUE-9250209 (HPLCPDA) and DUE-9750721 (NMR). Note W Supplementary materials for this article are available on JCE Online at http://jchemed.chem.wisc.edu/Journal/issues/1999/Sep/ abs1297.html.
Literature Cited 1. Alexander, C. W.; Asleson, G. L.; Doig, M. T.; Heldrich, F. J. J. Chem. Educ. 1999, 76, 1294–1296. 2. Libby, R. D. J. Chem. Educ. 1995, 72, 626–631. 3. Asleson, G. L.; Doig, M. T.; Heldrich, F. J. J. Chem. Educ. 1993, 70, A290–A294.
Journal of Chemical Education • Vol. 76 No. 9 September 1999 • JChemEd.chem.wisc.edu
