Pendulum Wave Toy

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You can see bigger versions of this scientific demonstration in museums and science departments. But we think this might be the first time it has been produced as an affordable table-top demonstration.
Fifteen ball bearings hang from a frame, suspended on fine threads. However this is not a version of the famous Newton's Cradle. Here the ball bearings are not touching, and in addition, each ball bearing has a different length of thread supporting it. The time a pendulum takes to move to and fro is dependent on the length of the pendulum. And here we have fifteen pendulums, all of different lengths!
Using the supplied wooden bar, move all the ball bearings to one side, and then move the bar out of the way. All the ball bearings start to swing from side to side. Initially they all (nearly) move together, but very quickly, other patterns start to appear....