So this is how they make Easter eggs! Put the hot liquid chocolate in a mold and spin it round. The chocolate tries to keep going in a straight line because it has inertia. The spinning forces act on the metal mold so they are pulled round in circles. The chocolate tries to keep going and hits the metal wall. The metal wall pushes back inwards on the chocolate: a centripetal force. The chocolate stays plastered on the edge, prevented from carrying on through the wall of the mold by this centripetal force. Many people say that the chocolate has been thrown to the outside by a centrifugal force. My Physics teacher argued otherwise but it was years before I understood why.
