A Foucault pendulum is a device that has been used to prove that the earth rotates. It was discovered in 1851 by a French physicist, Leon Foucault, who wanted to prove the earth's rotation and did so with his pendulum. Ideally, a Foucault's pendulum should rotate at a fixed point on surface of the earth but unless it is located at the poles, the pendulum is rotating as the earth rotates. When gravity is the only acting force on the pendulum, the pendulum will swing and rotate back to its original point in approximately 24 hours. Although the pendulum's would eventually stop due to air resistance, there is often an electromagnetic drive that is used to keep the pendulum going as it swings.
All around the world, there are now pendulums often in science museums and colleges. In our area, there are several within driving distance and I would love to go an see one soon.
Until next time,