The Foucault Pendulum show that the Earth rotates because the pendulum would swing so slowly that it would appear to change direction as the Earth moved away.
<h3>How does the Foucault pendulum work?</h3>
The Foucault pendulum was able to demonstrate experimentally that the Earth revolves around itself with an angular velocity Ω, in a period of 23 hours, 56 minutes and 4 seconds.
Thus, Foucault knew that the longer the string attached to the weight, the slower the swing of his pendulum. He could attach the string above to an almost frictionless pin, and if he used a very large weight, the pendulum would swing so slowly that it would appear to change direction as the Earth moved away.
