Foucault's pendulum (Ground floor and multimedia stand on the first floor)

The main idea of the installation is to demonstrate to visitors an experiment that proves the movement of the Earth around its axis. The deviation of the plane of oscillation of Foucault's pendulum from its initial position is the result of the Coriolis force - one of the inertial forces acting in a rotating reference system such as the Earth. The experiment was first demonstrated under the dome of the Pantheon in Paris on 26 March 1851, when Jean Bernard Leon Foucault used a pendulum of his own design to prove that the Earth rotated. The idea of his experiment, ingenious in its simplicity, assumed that if one took a sufficiently long and heavy pendulum, its motion would be approximately harmonic, and one could observe the deviation of the plane of oscillation of this pendulum from its initial position, resulting from the fact that this motion took place in a rotating reference system associated with the Earth. The effect of apparent forces, including the Coriolis force, can thus be observed. Foucault constructed a 67-meter-long pendulum with a 28 kg cannonball. The pendulum was set in motion by burning a thread attached to the surface of the ball. As the experiment progressed, the pendulum's plane of oscillation changed and, after prolonged observation, it could be seen that the center of the pendulum made a movement that circled the image of a rosette. The full rosette was drawn when the Earth made a full revolution. The demonstration made such an impression on the public that similar pendulums were built in various places around the world.
Toruń's Foucault Pendulum is 33 metres long and its heart weighs about 30 kg. The full rotation of its plane of oscillation (characteristic for our latitude ~ 53oN) takes about 30 hours. Its movement can be observed from the ground floor and parts of the other floors of the building. The change in its plane of oscillation is indicated by the gradual toppling of the posts placed on the perimeter of the plane under the pendulum. It will take just over 30 hours for all the posts to fall, so the multimedia kiosk on the first floor, on the railing to the left of the entrance to the exhibition, offers, among other things, a time-lapse film showing the movement of the pendulum over the previous 24 hours. The multimedia kiosk also allows visitors to learn about the physical basis of the pendulum's movement, as well as interesting facts about the history of the experiment and the influence of inertial forces on various phenomena observed on Earth.