School of Physics Lecture Demonstration Manual

Mk-2 Double Cone Paradox

Published: Thursday 09 March 2006 - Updated: Thursday 24 March 2011


To demonstrate the motion of the centre of gravity.



Click on pictures to enlarge.

Double Cone Paradox

Double Cone Paradox Pic


Double Cone Paradox


The apparatus consists of two wooden cones joined at their bases and a sheet-metal rail system as in the above photo. It has been designed such that the centre of gravity of the cones at the apex of the rail is higher than at the widest point of the rail. Subsequently if placed at the apex, the cone rolls up the incline to the widest point.

Safety notes


top of page