Chladni Plates - round, square, violin shape

Resonance of a 2 dimensional surface is made visible with sand. When the plate resonates some sections move up and down while other areas remain still. In the first case a round plate is attached only by a fixed bolt in the center. The plate flexes in a shape like a potato chip; switching alternately between being bent one direction and then the other. Where the plate moves a lot, the sand is bounced around randomly. This random motion results in the sand collecting is places where there is little or no movement; the node lines. On the round plate cases are shown for four and six radial segments.

Square plates show a couple of more complex resonance patterns.

A plate cut in the shape of a violin silhouette illustrates the multitude of resonance modes on more complex objects. It should be noted that this is a poor model for a real violin. Real stringed instruments have curved surfaces which vary in thickness. Also, the edges of our plate are free to move whereas a real violin's front and back surfaces are attached at the edges through the ribs and blocks.