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edited by: DELORENZO
Middle Georgia College Cochran, Georgia 31014
A Moire Pattern Analogy to Electron Motion James R. Bard Pen" Valley Community College Kansas City. MO 64111
T h e use of models to aid students in visualizing dynamic bitals in an atom simultaneously is often hard for students to grasp. Furthermore, many students, given the idea that the electrons in these orhitals are performing some sort of motion tend to equate the dumbell shape of a p orbital and the motion of its electron(s) in terms of the electron executing a figureeight movement from one lobe to the other through the nucleus. As pointed out by Oster and N i ~ h i j i m a moiri! ,~ patterns provide simple analogs of complex phenomena and have many applications in science. "MoirB" is the French word for "wat e r e d 3 and is familiar to most people in the term "moir6 silk"
or perhaps through familiarity with the more common moirb-look vinyl window shades. The surfaces of both materials have a shimmering appearance due to the moire pattern on each. Moirl: patterns appear when one repetitive design is not quite exactly superimposed on another, and the proper design can give an illusion of movement. I t is this illusion of movement in the moire pattern shown in the figure that, with a little suggestion from the instructor and some (perhaps much) imagination from the student, provides an effective visual analogy of what might he the motion of electrons in atoms. The illusion complements the models of atomic orbitals in helping students to visualize this dynamic system in that no definite periodic motion is observed (hence no set path followed by the electron). In addition, as the eyes focus on slightly different positions within the pattern the amarent motion is not restricted in size hut exoands. within atoms. -
Ediiw's Note: Or. Bard presents the moire patternto his class as a slide. If YOU wish lo use this same method of oresentation. vou can either prepare a slide from the figure shown above or, for a nominal fee to Cover his expenses, you can obtain a slide from Dr. Bard.
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' Cavagnol, R. M. and Barnen, T., J. CHEM.EDUC., 53,643 (1976)and
references therein. ? Oster. G and Nishqlma. Y.. Sci. Arne,.. 208, SO (May 196'3) ? Manson J E . IEdllor). "harrao s hcu Stanoaro French and tnqiish Dictionary" part I; V O I11:~harlei . Scribner's Sons, New York, N.Y., 1973. p. M:48.
This feature presents a collection of descri~tiveaoolicatione and analaaies de-
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