The demonstration of inertial forces in accelerated frames of reference. These forces do not occur in reference frames which are not accelerated (inertial frames). Rotating frames of reference are also accelerated even when the angular velocity is constant. In such a frame, the Coriolis force acts on moving objects in a direction perpendicular to their motion. For freely moving objects, this leads to a curved path. Such paths, in the form of rosettes, will be shown for a simple pendulum swinging on a rotating chair. This experiment is in principle identical to that of the Foucault pendulum, with the earth being the rotating reference frame, the only difference being that the earth rotates about ten thousand times more slowly than the rotating chair in the lecture hall.