PURPOSE: Geometrical model of the Michelson-Morley experiment to aid explanation.
DESCRIPTION: An laser-light interferometer is set up on a cart with a screen on a long arm. Interference fringes can be seen on the screen. When the system is rotated, there is no displacement of fringes on the screen, indicating that the postulated motion of the earth with respect to the supposed "ether" does not influence the speed of light.
REFERENCES: (PIRA unknown.)
EQUIPMENT: Interferometer with screen on long arm.
SETUP TIME: 5 min.
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