Dynamics: Pendulum Systems

The Foucault pendulum

Fig. 14-11: The Foucault pendulum

Fig. 14-11 shows a huge brass pendulum that swings across the lower foyer in the Manchester Conference Centre at the University of Manchester. The pendulum was set up as a tribute to Jean Bernard Leon Foucault.

Jean Bernard Leon Foucault (1819 - 1868), a French physicist, demonstrated the earth's rotation using his famous pendulum. He suspended a 28 kg bob with a 67 m wire from the dome of the Pantheon in Paris. Foucault was acclaimed by witnesses for proving that the earth does indeed spin on its axis. As the plane of the pendulum oscillation remained unchanged with the stars, they could understand that the Pantheon moved around the pendulum, and not vice-versa!

Foucault's pendulum was the first dynamical proof of the earths rotation in an easy-to-see experiment.