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Weird Acoustics - Sand and Salt Answered

I found this video and wanted to know your reactions.
http://www.youtube.com/watch?v=IuyQSZX8HMI&NR=1

any1 knoow if it is real?

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NachoMahma (author)2007-10-30

. Real as can be. It looks like they are using a transducer on each corner, but you can get similar effects with just two.

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Kiteman (author)NachoMahma2007-10-31

There's just one, vibrating the central post up and down. The plate vibrates at different frequencies, waves travelling through the metal. The salt settles at the "nodes" of the waves (where the metal is moving least). The distance between patches of salt are half-wavelengths long. Notice, class, as the pitch goes up, the patches of salt get closer together because the wavelength shortens as the frequency increases (for a constant wave velocity).

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NachoMahma (author)NachoMahma2007-10-31

. hmmmmm Judging by the iBle that Tool Using Animal posted, it only requires one.

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Goodhart (author)2007-10-30

Oh it is real alright. I remember asking this person:

https://www.instructables.com/id/The-Rubens_-Tube%3a-Soundwaves-in-Fire!/

Have you ever fooled around with Chlandni Plates ?

http://www.phys.unsw.edu.au/jw/chladni.html

http://www.physics.utoronto.ca/nonlinear/chladni.html

Maybe not as exciting as FIRE but definitely interesting (at least they were to me).

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gmoon (author)2007-10-30

These are called "Chladni patterns." A related story popped up a year or so ago: Da Vinci Coda

Composer Stuart Mitchell thinks the glyphs in the Rosslyn Chapel (of Da Vinci Code fame) are representations these patterns. He composed a piece using the symbols as a guide.

He also believes other images in the chapel represent the musical staff. On second view, I think your youtube video is one of Mitchell's...

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NachoMahma (author)gmoon2007-10-30

> On second view, I think your youtube video is one of Mitchell's . Other than the intro, it is. Same "lab", same hand, &c.; . . Thanks for including the links.

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gmoon (author)NachoMahma2007-10-30

Sure. Beats me if any historians or scientists take his theory seriously....but it sure is fascinating.

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Brennn10 (author)2007-10-30

First of all, I think I am deaf now. Second, it looks pretty real to me. The vibrations, (I believe) cause the salt to move. Somebody correct me if I am wrong.

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