| a pendulum that demonstrates the rotation of the earth by exhibiting an apparent change in its plane of oscillation. |
| Foucault pendulum n. A simple pendulum suspended from a long wire and set into motion along a meridian. The plane of motion appears to turn clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere, demonstrating the axial rotation of the earth. [After Jean Bernard Léon Foucault.] |
| Foucault pendulum
A pendulum suspended from a long wire, set into motion, and sustained in motion over long periods. Due to the axial rotation of the earth, the plane of motion of the pendulum shifts at a rate and direction dependent on its latitude, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. At the poles the plane rotates once per day, while at the equator it does not rotate at all. |
