The overhead projector is perhaps passing out of use, but it is still a useful device with which to do lecture demonstrations. In my early years at Kenyon I was teaching the pre-med course, and found that the overhead projector was an ideal platform for showing the phenomena of polarized light. This note is a discussion of how I learned to use the projector for these demonstrations. Now that I am in my eighth decade, I would like to pass on some of my earlier teaching techniques to my younger colleagues.

1.
J. Dorman
Steele
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(
A. S. Barnes & Company
,
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An experiment on sky polarization and brightness
,”
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and
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,”
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,
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(Nov.
1997
). This article has some splendid color photographs of the effects of birefringence.
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Robert
Mark
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(
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P. J.
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,”
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,
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2002
).
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