Re: Chladni figures...

[William Beaty <billb@eskimo.com>]

On Mon, 2 Sep 1996, Delissa Souder wrote:

> Greetings!  I was wondering if anyone has ever tried making chladni 
> figures as a lab or demo?  If so, could you give me some advice on doing 
> so?  What materials did you use?  What type of patterns did you get?  
> I've tried using a metal disk (galvanized sheet metal) supported at the 
> center and various "bows" to produce the sound vibrations.  I've been 
> unsuccessful and was wondering if there is anything else I could use that 
> is readily available.  Any help would be greatly appreciated.

"Sounds" like your problem may be with overly thin metal.  You'll need a
plate which is thick enough to be somewhat rigid.  When you support it
horizontally upon three fingers and then give it a good whack with your
knuckle, it should go "Boonnnnnnnnnnng" and not "clank."  Sheet metal
might be too thin, so it couples to gas, loses energy, and acts as a
transformer rather than an oscillator.  The plate must act like a sort of
bell.  Bells work best if thick metal, not sheet metal. 



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