Rolling Double Cone


Rolling Double Cone


The rolling double cone serves as a demonstration of how gravity acts on an object’s center of mass. When released, the edges of the rolling double cone appear to move up its triangular support, but in reality the cone’s center of mass is still rolling downwards. The concept of the center of mass is older than the rolling double cone, which seems to have become a popular instrument in the 1700s. Some early versions of the cone were less elegantly constructed from rulers and screws, and could produce results that were unreliable. Nevertheless, its simplicity made it a useful and easy-to-understand demonstration when well carried out, and it was well-known in England by the eighteenth century. Several textbooks and course outlines from that time period cite it as one of the more important phenomena to be understood when it came to understanding laws of gravity and motion. The rolling double cone experiment was used in classrooms and illustrated and explained in textbooks to help explain to students how gravity worked. It is still being used in introductory physics classes at Grinnell today, as a way of demonstrating the importance of the concept of center of mass, and to show how counterintuitive it can be.

-Lilly Haight 2018


Clarke, Henry. The rationale of circulating numbers, with the investigations of all the rules and peculiar processes used in that part of decimal arithmetic. To which are added, several curious mathematical questions; With Some Useful Remarks on Adfected Equations, and the Doctrine of Fluxions. Adapted to the Use of Schools. London, 1777, pp. 89.

Desaguliers, John T. A course of mechanical and experimental philosophy. Whereby any one, although unskill'd in mathematical sciences, may be able to understand all those phænomena of nature, which have been discovered by geometrical principles. London, 1725, pp. 3.

Desaguliers, John T. A course of experimental philosophy. London, 1763.

Worster, Benjamin. A Course of Experimental Philosophy. London, 1730.






Storage Location H4a