Dancing Corn Starch!?!?!

Hey, yesterday I did a totally awesome experiment with dancing corn starch. I suggest doing this in the basement or out side where it's okay to get messy and there's an outlet. You'll need a junky old speaker to use and you'll have to hook it up to an amplifier with a computer to generated the sound. I use a Mac so I got a free app called Tone Gen from the apple website so for those who have PC's you'll have to look around or hook up a keyboard. You'll need the corn starch (you can find it at super markets) to be at the consistency that you can punch it with your fist and it will be solid. For those who don't know what corn starch is, it's a powder used as a thickener in gravies instead of flower and if you mix in with water it has the cool property of being "Non-Newtonian", meaning when you squeeze it, it's a solid and when you let go it's a liquid. So, when you mix up the corn starch I suggest putting it on a Styrofoam plate if your speaker cone is cloth, and putting the plate on a plastic bag so you don't end breaking the speaker. Then if you have the app set it to a single tone ( I suggest 28 Hz if your speaker can go that low, though it works to about 35 Hz). If you only have a keyboard you'll need to go as low as you can and if you have a tuba setting you should do that and crank up the volume as high as it can go without the amplifier burning a fuse or the speaker popping. once you have this set up, hopefully it will start wiggling in the middle and you can get it to move around a pit by poking it with a pencil (or using your hands ;-). If you have the computer set up you can play really loud music in the background :-) So, you know, the louder the volume the more it moves around.  

             So what I think is happing is that with all liquids low sound makes them vibrate and make cool patterns. With corn starch it has more of a structure with all the vibrations, becoming semisolid making the patterns be able to "climb". while this stuff is out a fun thing to do is to do a hearing test. Start at 1 Hz and go up on single tone with the plus and minus buttons in the top left corner, seeing how high and low you can hear.

         note: be careful when going to high Hz and let the tester change the volume so you don't end up shattering their ear drums. Also, don't listen to the high notes for more than a minute or two because it might cause ear damage.