Resonance & Rice
 

Only word that comes to mind is "WOW"...

:snap::snap::snap:

That scared the hell out of Buster.

That's one of my favorite videos ever. Science rules.

Shoot, there was another similar video that went around some time back, but I can't remember what it was exactly. Some material that acted weird at different ressonant frequencies. Damn.

It is a cool video but is calling it a demonstration of resonace correct?

This is just a visualizing of the points of high and low vibration on the speaker surface and has nothing to do with matching the vibration of the sound to the natural vibrations of the rice. This is the equivelant of using iron shavings to visualize a changing magnetic field.

But the relevant physics classes are well behind me so maybe I'm misremembering.

The resonance in this case would be the resonance with board that's sitting atop the speaker. The rice aligns with the resonance patterns there. At least, that's my semi-educated interpretation.

Here is my understanding of resonance:

Resonance is when the frequency of one thing matches the natural frequency of another allowing for a much greater transfer of energy from one to the other.

To my understanding that demonstration is not of two vibrations in synch but rather simply (though still coolly) a visualization of the vibration of just one thing, the vibration of the soundwaves as they pass through the board.

I have no problm accepting that I'm probably wrong. Just trying to piece together why.

But notice how it's not a smooth transition from one pattern to another? I believe that's a result of the reaction of the board to different resonant frequencies. You see the rice snap into a very defined pattern, and then it drifts away from that pattern, and then snaps into another pattern. That looks to me like a demonstration that the board is resonating in characteristic patterns at certain frequencies.

Probably, but I saw it as the acoustics of the underlying sound chamber producing different patterns of interference in the surface.

Yeah, could be that too. *shrug*

I wanna see the effects of resonance and mashed potatoes :D