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Show two-dimensional standing waves in a metal plate

Sand is sprinkled onto a circular or square thin metal plate, which is then stroked along the edge using a violin bow. The sand moves to nodal lines of the standing wave pattern. Stroking at one point while holding your finger at another point to forces a node at that point, if desired, creating a variety of standing wave patterns.

A nice article describing the Chladni plates at the Whipple Collection wil be found by clicking http://www.hps.cam.ac.uk/whipple/explore/acoustics/ernstchladni/chladniplates/.

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