Ellen sent me this link:

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It shows sound waves being blasted through salt crystals on a square surface.  The salt crystals form standing wave patterns that alter as the frequency of sound changes.  The comments below the video are interesting as well.  For example:


Quote:

These are classic standing wave patterns. Now, Garble, to answer your question, the reason that the wave patterns are not perfect circles is that the vibrating medium is not a circle, but a square. If the experiment had been done with a circular flat disc, many of the patterns would have resembled bulls-eye targets. These patterns are actually visible representations of solutions to complicated sets of differential equations, which exist for practically any shape. Standing waves in circular membranes have been studied extensively, because (a) they are a relatively simple case, and (b) they have practical application in the design of drums i.e. controlling the pitch and getting "good sound".

WARNING:  Watch this with the sound off if you're in cycle.  Please.  Also, clear the room of any animals you might have around.  I can tell you for a fact that the sound will make cats and dogs go ape$%*&.

Best,

George

That is beyond cool.

Max just sat at his food dish eating.  Never gave it a moments notice.

That was very cool.  Nikita (our Sheltie) wasn't too bothered by it, but my ears hurt at the end. :-/

thanks for posting this george. very cool. i'll have some fun playing this at low volume while robbin is watching tv. i wonder if figure out what it is. :D

Cool.

   Potter