The Foucault Pendulum

The Foucault Pendulum is a device that demonstrates Earth's rotation. It consists of a large, freely swinging pendulum that initially swings in a fixed direction. Over time, the pendulum's swing appears to rotate relative to Earth's surface because Earth is rotating underneath it. This effect provides visual evidence of Earth's rotation without relying on astronomical observations. The pendulum's plane of oscillation remains constant in space, but as Earth turns, observers see the swing direction change, illustrating the Earth's rotation in a simple, elegant experiment.