A few years ago, The Physics Teacher published two very interesting papers describing experiments involving pendulums. The first article1 described an easy way to create, using magnets, a pendulum that exhibits a chaotic behavior. The second paper2 showed how a spark generator coupled to a spherical pendulum could be used to “trace” and study two-dimensional trajectories such as Lissajous patterns, ellipses, and circles. In this paper, those two ideas were joined to develop an experimental apparatus, the “chaotic sparking pendulum,” that reveals chaotic two-dimensional orbits of a pendulum sliding over a set of magnets.

1.
D.
Oliver
, “
A chaotic pendulum
,”
Phys. Teach.
37
,
174
(March
1999
).
2.
R. S.
Worland
and
M. J.
Moelter
, “
Two-dimensional pendulum experiments using a spark generator
,”
Phys. Teach.
38
,
489
492
(Nov.
2000
).
3.
H.O. Peitgen, H. Jürgens, and D. Saupe, Chaos and Fractals: New Frontiers of Science (Springer-Verlag, New York, 1992), p. 758.
4.
The simulations were performed using the Maple™7 software from Maplesoft; http://www.maplesoft.com.
5.
Some discussion regarding the dependence of the bob movement with the initial conditions can be found at http://mathforum.org/advanced/robertd/magneticpendulum.html.
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