Describe how Foucault's pendulum demonstrates that the Earth is rotating on its axis.

Foucault's pendulum, a simple pendulum that swings freely in any direction, demonstrates that the Earth is rotating on its axis through the observed precession of its plane of oscillation. The Earth's rotation causes the Coriolis effect, which influences the pendulum's motion and makes it appear as if the plane of oscillation changes. The rate of precession can be described mathematically as \(T = \frac{24}{\sin \phi} \ hours\), where \(T\) is the period of precession, and \(\phi\) is the geographical latitude. The variation of precession period based on latitude confirms that the precession is due to Earth's rotation, not an intrinsic property of the pendulum itself. If the Earth were not rotating, there would be no observed precession.