Movement of particles on vibrating plate

[whatisreality]

So our professor showed us wave patterns on a vibrating plate, by sprinkling powder over it. I'm curious as to why it behaved as it did.The powder moved to nodes, but I'm not sure why. I think it just gets bounced around until it lands on a node, which is stationary, so it then stays there.
Is there a slightly more scientific way of explaining this? Or at least a different way of wording it (if I'm right at all) ?

 

[brainpushups]

You are correct. It is analogous to playing harmonics on a stringed musical instrument. Lightly touch a guitar string at half the string's length and pluck it and the string will vibrate even though the point you touch is held stationary.

I remember when I first saw that demonstration; they are fun. Try it yourself with different shaped plates (make sure you have some good earmuffs!)