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Jam on a Wooden Harmonica

by Rani Arbo

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Total Time Needed:: 1 Hour

This wooden harmonica is one of the hottest items at the Carnegie Science Center 's community outreach programs. "We've made these with at least half a million children," says educator Elizabeth Pagel-Hogan. "Once a few of these harmonicas get dispersed into the crowd, our tables are swamped with kids asking, 'Is this where you make the noisemakers?' "

According to Pagel-Hogan, children up to age 5 may need help assembling one, but older kids can whip up these tunable wind instruments in minutes — and enjoy them for hours.

Here's how it works: when you blow through the harmonica, the air passes through and over the paper sliders, causing them to vibrate and create sound waves. When you move the paper sliders into the middle, they vibrate faster, creating a higher pitch. When you separate them, they vibrate more slowly, creating a lower pitch. The result isn't exactly Mozart, but as Pagel-Hogan says, "Kids don't care, as long as it makes noise!"

Materials

Two tongue depressors
Colored tape, stickers, and crayons
Scissors

Paper
Clear tape
3 wide rubber bands (like those used to bind vegetables)

Instructions

Decorate one side of each tongue depressor with colored tape, stickers, and crayons (avoid markers or paint, which may come off on kids' lips).
Make the paper sliders by cutting 2 strips of paper about the same width and length as a tongue depressor. Stack the tongue depressors together, wrap each paper strip around the stack, then cover each loop with a layer of clear tape.
Remove the sliders from the stack, separate the tongue depressors, and slide the sliders back onto just one of the tongue depressors. Stretch the thick rubber band lengthwise over the tongue depressor and both sliders.
Restack the tongue depressors (plain sides in) and wrap a rubber band around each of the ends (you can also use colored tape).
To play, blow in the middle and move the sliders back and forth to change the pitch.