Foucault's Pendulum Demonstrates Earth's Rotation

On February 3, 1851, French physicist Léon Foucault conducted the first public demonstration of Earth's rotation using a pendulum at the Paris Observatory. The experiment showed that a freely swinging pendulum appears to rotate its plane of oscillation as the Earth rotates beneath it. On March 31, 1851, Foucault created a larger version at the Panthéon in Paris, suspending a 28-kilogram brass-coated lead bob on a 67-meter wire from the dome. This provided the first laboratory proof of Earth's rotation that did not rely on astronomical observations.