Foucault Pendulum

The Foucault pendulum demonstrates the rotation of the Earth through the gradual shift in the pendulum's plane of oscillation. In this setup, the pendulum is suspended from a length of 70.5 feet (21.5 meters) and weighs 238 pounds (108 kilograms). With a period of 9.3 seconds, the pendulum swings back and forth in a fixed plane, but because of the Earth's rotation, the plane of its swing appears to slowly rotate over time. The pendulum's motion is governed by the principles of inertia and the Coriolis effect. In a non-rotating reference frame, the pendulum would continue to oscillate in the same plane. However, from the Earth's rotating reference frame, the plane of oscillation rotates at a rate dependent on the latitude of the pendulum's location. At the poles, the plane would complete a full rotation in 24 hours, while at the equator, there would be no rotation. This demonstration provides a direct and observable indication of the Earth's rotation.