Foucault's Pendulumn
In 1851, Foucault carried out an experiment at the Pantheon in Paris to prove the rotation of the earth.
In the experiment, a huge pendulum with a 60cm diameter, 28 kilogram weight and a 67 meter long steel cable was used. A nail was affixed to the weight of the pendulum and as the pendulum swung, the nail traced a line in the sand scattered on the floor below it. It is said that when initially swinging the pendulum, in order to avoid unwanted oscillation, the pendulum was held to one side with a length of string affixed to a wall, and was released by burning the string.
If you carried out this experiment at the North Pole, from the point of view of the outside universe, the pendulum would swing within a stationary plane, so from the point of view of the earth, the pendulum takes one day to do a full rotation. At latitudes other than the poles, the pull of gravity is not parallel to the axis of rotation, so it takes more than one day for the pendulum to come the full circle.
