Science fair help... (acoustics)?

Question

it's that time of the year again...science fair..

I'm thinking about doing something on acoustics, and i saw this video on youtube (http://www.youtube.com/watch?v=s9GBf8y0lY0&feature=related), but I don't know how i can turn this into an experiment..

..so questions are:

-what causes the rice to form patterns? (links to websites would be really helpful)

-can this effect be recreated easily with any large speakers?

-What kind of experiments can be done with this thing?

Answer 1

If the video is real, then the sound is causing the surface to vibrate with wave patterns.  The rice would accumulate at the parts of the surface that are not vibrating.  Sorry, this is intuition on my part, and I don't have a link for you.

I don't know if this would be easily reproducible.  I guess there are 3 main components:  a surface, a speaker, and something that produces sound of a single frequency.  The thing producing the sound might be tough to find or expensive, some speakers might not be very capable of emitting a single frequency, and you might need to try several surfaces so that you can find one that vibrates with enough movement to rearrange the rice, but which isn't so mobile that the rice all just flies off.

Experiments would be to test different surfaces to compare whether and how the patterns differ, to test various speakers to see if they are all able to generate the same patterns, and to test things other than rice to see if different patterns arise.

If you could work it out, it might be a pretty cool demonstration.

The person who posted the video at the link below seems to know a bit about it  ... maybe you could e-mail them and ask for advice?

Good luck.