Chemical Education Today
Letters Playing-Card Equilibrium From experience, I am hypersensitive to the misconceptions of students and instructors that can be caused when playing cards are used in teaching chemistry (1). The root of such errors lies in overlooking the non-mobile, non-energetically-interacting nature of pieces of cardboard. Only if they are being shuffled can cards serve as some sort of analogy to molecular behavior in chemistry. Thus, I found Hanson’s “Playing-Card Equilibrium” of special interest (2). To me, his otherwise excellent treatment of probability in relation to chemical equilibrium lacked emphasis on shuffling as a vital element in the analogy. However, in a personal email, Professor Hanson said that his experience with teaching teachers did not show that they over-
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looked the importance of constant shuffling to simulate the interacting state of molecular movement. His summary is my view also: “The shuffling illustrates the equilibration, and counting the probabilities from the card arrangements at any moment is like taking snapshots of that dynamic process.” Literature Cited 1. Lambert, F. L. J. Chem. Educ. 1999, 76, 1385–1387. 2. Hanson, R. M. J. Chem. Educ. 2003, 80, 1271–1274. Frank L. Lambert Department of Chemistry Occidental College Los Angeles, CA 90041
[email protected] Vol. 81 No. 11 November 2004
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Journal of Chemical Education
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