This paper describes a new approach to the traditional iodine gas absorption spectrum experiment often performed in undergraduate physical chemistry labs. The approach is student centered and designed to emphasize the conceptual richness in this classic experiment. It gives students the opportunity to examine the conceptual and mathematical connections between spectroscopic data and quantum models by organizing the material in conceptual chunks, which they work through sequentially. Students use symbolic mathematics software, Mathcad, to expedite the sophisticated numerical calculations required. The curricular chunks were specifically constructed to make the sophisticated concepts embedded in the project accessible. The focus activities remind the students of information they already know and require them to employ both paper and pencil and computer worksheets to complete calculations. Five Mathcad templates provide a rich mathematical treatment of the topics in this experiment. This paper describes how the documents MorsePotential.mcd, BirgeSponer.mcd, IodineSpectrum.mcd, FranckCondonBackground.mcd, and FranckCondonComputation.mcd are used during the three weeks in which this experiment can be performed by a typical physical chemistry student. Although originally designed to use the WWW to disseminate information and promote interaction among physical chemistry students at geographically dispersed institutions, this segmented focus-question approach to the iodine experiment has also been used by a physical chemistry class at a single campus. In both formats, faculty noticed decreased anxiety of the students towards the experiment and an increase in the quality of laboratory reports that indicated better understanding of the chemical concepts.
More Information
Citation
Long, George; Sauder, Deborah; Shalhoub, George M.; Stout, Roland; Towns, Marcy Hamby; Zielinski, Theresa Julia. J. Chem. Educ.1999, 76, 841.
Keywords
Laboratory Instruction; Excited States / Energy Transfer; UV-Vis Spectroscopy; Iodine; Collaborative / Cooperative Learning; Physical Chemistry; Quantum Chemistry
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