PURPOSE: Demonstrate the Pulfrich phenomenon.
DESCRIPTION: A three-dimensional crystal model is placed at the center of a 33 1/3 RPM turntable and its shadow is projected on a white screen. An observer views the shadow with both eyes while holding a dark filter over one eye to see apparent rotation of the crystal model. Holding the filter over the other eye, the crystal model appears to rotate in the opposite direction. Polaroids or any other dark color filter can be used; we use one filter from a pair of red/blue stereo goggles.
REFERENCES: (PIRA unknown.)
EQUIPMENT: Crystal model, 33 1/3 RPM turntable, Bright point light source, and dark filters.
SETUP TIME: 5 min..
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