A Foucault pendulum is a simple device that demonstrates the rotation of the Earth. It consists of a heavy weight suspended from a long string, allowing it to swing freely in any direction. As the pendulum swings, its plane of motion appears to rotate over time, illustrating the Earth's rotation beneath it. The pendulum was named after the French physicist Jean Bernard Léon Foucault, who first demonstrated it in 1851. This experiment provides a visual and tangible way to understand the concept of Earth's rotation, making it a popular exhibit in science museums and educational institutions worldwide.