the coolest thing EVER, bar none.

so, these are pics of metal plates covered in sand that show the patterns created by vibrations at different frequencies. the plate wiggles around, shifting the sand to the parts that don't move. the patterns are reproduceable (20.149kHz will always make the shapes above). so cool! so elaborate! who knew? here's a quote from the internet:
"Chladni observed that when a metal plate covered with sand or other similar substance was made to vibrate by running a violin bow across it perpendicularly, a pattern emerged in the sand. Through careful documentation he theorized that sound affects physical matter and that these changes can be repeated. He produced diagrams of his experiments which came to be called, "Chladni figures."" this guy was also the 1st to theorize that metorites came from outerspace, not volcanoes, as previously thought.

the website today is www.physics.utoronto.ca/~nonlin/chladni.html is a good site for pics of Chaladni figures, but check around the web if you want to know the actual physics of it.