What it shows:
Fifteen uncoupled simple pendulums of monotonically increasing lengths
dance together to produce visual traveling waves, standing waves,
beating, and random motion. One might call this kinetic art and the
choreography of the dance of the pendulums is stunning! Aliasing and
quantum revival can also be shown.
How it works:
The period of one complete cycle of the dance is 60 seconds. The length
of the longest pendulum has been adjusted so that it executes 51
oscillations in this 60 second period. The length of each successive
shorter pendulum is carefully adjusted so that it executes one
additional oscillation in this period. Thus, the 15th pendulum
(shortest) undergoes 65 oscillations. When all 15 pendulums are started
together, they quickly fall out of sync—their relative phases
continuously change because of their different periods of oscillation.
However, after 60 seconds they will all have executed an integral number
of oscillations and be back in sync again at that instant, ready
to repeat the dance.
