PURPOSE: Show the view of a slide through a prism and argue about color theory.

DESCRIPTION: A 60 degree prism is mounted in front of a slide projector lens such that it can be rotated. The slide used is that of a plain white surface with some marking to show orientation. When projected so that the prism disperses, it add s color only to the edges of the field of the projected slide At another prism angle a mirror image of the slide is seen due to internal reflection in the prism.

SUGGESTIONS: The German poet and naturalist Goethe expected to see the white walls of his room in brilliant colors when looking through a prism, and rejected Newton's color theory on the basis of this experiment.

REFERENCES: (PIRA unavailable.)

EQUIPMENT: 35mm slide projector with slide showing large colorless (white) surfaces with mounted equilateral prism.

SETUP TIME: 5 min.

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