PIRA 6H35.50
| The photo at right shows some of the items for the birefringence demonstration. They include two polarizers, a plastic shape for showing stress figures, pieces of mica, and other items. Many of theses items are in a plastic bag. | |
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These two photos show the plastic shape betweeen crossed polarizers. In the left photo, the plasic is unstressed. In the right photo the plastic is stressed. | 
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This photo shows several pieces of mica between crossed polarizers, all at slightly different orientations. The mica pieces can be turned to show different patterns. |