Dancing Goop

Do you want to see sound? Kai shows us how mixing up some oobleck (cornstarch and water) and placing it on a speaker will make the sound waves come to life!

KAI: I like to make things and learn about things in my own way. I’m Kai and I’m a hacker.

KAI: Today, I’m gonna try and see how sound waves move. When I drum or play guitar, I can feel the sound waves vibrating. It would be so cool if I could actually see those sound waves. If you make some goopy goop, put it on top of a speaker, you might be able to see the goop jump around from the vibrations. Well, it’s not really goop. It’s corn starch mixed with a bit of water. Some people call this stuff ublack (SP). If you squeeze it, it’s hard, but if you hold it in your hand, it oozes like liquid. So, I’ve got this second hand stereo that my Mushum (SP) bought from a thrift store for real cheap and I’ve taken off the cover of one of the speakers. So I put a layer of plastic wrap over the speaker like so. Then I scoop some of my goop onto the plastic. Then I try a song with lots of bass. This one’s called All My Relations and it’s by Oz 12.

KAI: Look at it dance around. You can see the vibrations. Pretty cool huh? Now what happens when I put the goop onto a plastic tray? I’m gonna try some sound vibrations at different frequencies. 100 hertz. 60 hertz. 40 hertz. The goop is forming little fingers, and it does that because it behaves like a liquid and a solid. When the vibrations put pressure on the goop, it takes on more of a solid form, but as you can see, it is still quite liquid. Now what happens if I add some food coloring?

KAI: And there you have it. It’s so cool to see sound waves come to life.