PURPOSE: Demonstrate perception of color due to periodic excitation of the eye.

DESCRIPTION: A disc contains half black and half white fields with various sets of azimuthal black lines on the white field. Rotating the disc a few times per second creates circles which appear to have various mild coloration, from greens to browns to blues. Rotating in the opposite direction changes the colors.

SUGGESTIONS:

REFERENCES: (PIRA 6J11.11)

For further information on the Benham disk see tha Exploratorium site:

EQUIPMENT: Slow rotator and black and white discs with various azimuthal patterns.

SETUP TIME: None.