Foucault's Pendulum

Proof that Earth rotates — demonstrated since 1851

Rotation Period
Swing Angle
Elapsed
0h 0m
48° N (Paris)
Slow

In 1851, Léon Foucault suspended a 67-meter pendulum beneath the Panthéon dome. Its swing plane rotated slowly — not because of the pendulum, but because Earth itself rotated beneath it. The rotation rate depends on latitude: fastest at the poles, zero at the equator.