CHAOS ON A STICK
Devices that demonstrate true chaotic
behavior (in a strict mathematical
sense) are rare. Even rarer are chaotic
devices that are easy enough for the
typical maker to build at home and are
interesting and beautiful. But one device
nicely fits the bill: the double pendulum.
A double pendulum consists of a bar swinging from a pivot,
with a second pendulum attached to the first bar’s end.
While the double pendulum is a simple physical system,
you’d be hard pressed to find another device this simple that
exhibits so wide a range of behavior. Give it a little push and
the motion is fairly predictable. But give it a bigger push —
bingo, welcome to chaos!
The double pendulum described here was designed with
several options for demonstrating a variety of chaotic
motions. With the right mounting, it’s an interesting if not
downright charming display that fits well into a number of
settings, including classrooms, laboratories, and homes.
Photograph by Sam Murphy
Set up: p. 95
Make it: p. 96
Use it: p. 99
William Gurstelle (
bill@makezine.com) is a MAKE contributing editor and the author of the book Absinthe
and Flamethrowers: Projects and Ruminations on the Art of Living Dangerously.
93 Make:
