Leon Foucault (1819 – 1868), French physicist and inventor set up his first pendulum in the Pantheon in Paris in 1851. The construction -a pendulum that is able to oscillate in any toll, vertical plane for hours- serves to present the rotation of the Earth; it demonstrates well the turning of the oscillation plane.
How to use?
You may try the Foucault-pendulum in Agora! You have to fix the oscillation space with lighting the LED light.
What happens?
Observe where the pendulum’s oscillation plane is! If you wait a few minutes, you will see that the oscillation plane is not where you have seen it a moment before. If you wait a little longer then you will be able to define the turning of the oscillation plane in order to calculate how long the pendulum’s oscillation plane would need to turn around entirely. In reality not the oscillation plane changes but the Earth rotates under the pendulum, according to the first principle of Newton. The oscillation plane rotates around at the poles entirely over a day. As moving closer to the Equator, the turning gets slower and it utterly ceases at the Equator.