Abstract. A method is described of enhancing a demonstration of a falling beam, initially carrying a pair of ball bearings, so that an observer can compare and contrast the motion of objects in free fall with that of an extended body constrained at one point. The physical principles of falling, while rotating about a fixed point, are discussed in the special case of the thin rectangular beam. The location and particular properties of the centre of oscillation provide interesting insight into the process, both in terms of the relevant equations and for the demonstration itself. The optimal initial angle of inclination of the beam is for viewing the separate motion of a ball bearing placed at the end. Even under optimal conditions, the visual quality and impact of the demonstration are greatly improved by use of a video camera and digital image storage for repetition in 'slow motion'.

Print publication: Issue 1 (January 2004)
Received 16 April 2003
Published 15 October 2003