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Airdate: Oct 06, 2010
Scientist: Bart Hopkin

Spritzer Whizzer

Spritzer Whizzer
What does it take to design a completely new kind of musical instrument?

Bart Hopkin turns on Savart's Wheel

BH: People run screaming from the room when they hear it, usually, but it's one of my favorite things that I've made.

JM: That's experimental musician Bart Hopkin playing his own musical invention. I'm Jim Metzner and this is the Pulse of the Planet.

There was a 19th century physicist named Felix Savart, who had done a very simple version of this a one note version of it as a classroom demonstration for the idea that frequency corresponds to pitch.

Hopkin called his invention Savart's Wheel. His version plays many notes using a series of rotating discs with ridges cut into them. When you hold something against those ridges in this case a Styrofoam cup the cup vibrates, producing this sound.


BH: Now, you know I'm Irish, so I'm sort of a sucker for sentimental old songs like that. So-

BH: I had been thinking about this question of do all musical instruments have to have this kind of natural, springy, oscillation that comes from, say, a vibrating string that's-naturally springs back and forth at its own frequency or the air inside a tube, which has a springy quality and naturally wants to spring back and forth? I was asking myself, "What if you tried to make an instrument where you just forced it, forced something to vibrate at a certain frequency," and I was challenging myself with this question. Could I make something that would basically just go back and forth 440 times a second?

JM: It may not sound pretty, but it worked. Now, what kind of new musical instrument can you dream up? That's the question for this year's Kid Science Challenge, our free nationwide competition for third to sixth graders. Learn more at kidsciencechallenge dot com. Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.

End song and BH turns off Savart's Wheel