Notes on

The Indian Rope Trick







This is a collection of notes and applets collected on a problem we encountered on an outing to Cambridge. Here the happy band of warriors are posed outside the Cavendish Laboratory before we went into the Whipple.

A highlight of the trip was the lecture at CMS by Professor Michael Thompson. Here is a photo of the kids afterword with the Professor... you can see their excitement (and part of the lecture) written all over their faces...

Here is a document that Professor Thompson sent us from a book by Michael Acheson that explains a little about the work on the problem.

From Professor Acheson's web page you can download this demonstration and description of the central problem of the Indian Rope Trick

You can also download and/or run this program showing the ideas of the multiple pendulum problem.

Here is a link to the double Pendulum applet from the web page of Professor Thompson and Takashi Kanamaru. Hours of fun you can't take your eyes off, and the patterns of the phase diagram are fascinating. You can also download a zip-file of the demo to work off-line if you wish. Here is a photo of one we ran for a few hours.

Here is another link to an undamped (no friction) double pendulum system that allows you to alter the lengths of the pendulums and the weight of the masses at the end.

Professor Thompson, who has been incredibly patient in helping me find tools to explain these ideas also sent a link to Power-point slides from his recent lectures.


Here is a picture of James Hyslop at the Whipple giving us an overview of the workings of a 14th century astrolabe.