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The store-bought version of the slinky & ceiling tile would, perhaps, be
the thunder drum.  It's an effective sound toy, simply a spring attached
to a small drum head on the end of a cylinder.  I also love our
theremin--one of the earliest electronic sound devices.  We have 2 of
the Big Briar version, a pretty stable one.  People love to play it, it
has cool stories behind it, and one antennae controls frequency while
the other controls amplitude.  Sometime we bring it out for Halloween,
too, as it can easily make spooky sounds.  In our Making Waves program,
we hang a microphone over the theremin amplified speaker and we project
the waves real-time using a science interface.  A mechanical wave table
oscillator projected real-time and at the same time shown in side view
using a flex-cam is another visual component of that program and you get
a good view of the wavelength changing with a change in the frequency of
the vibrator.  This demo is better in a darkened room, as is showing the
vibrations of a speaker with lasers aimed at a mirror glued to the
speaker's surface.  Blown speakers work fine for this and the farther
away the mirror is from the projection screen, the larger the patterns. 

I can't remember where I saw this demo at a sound stage show years ago,
but a circle was cut out in a bass drum head to blow out a candle across
the stage when the drum is hit.  Last to mention, one of my favorite
homemade instruments is a set of large PVC pipes cut to different
lengths to produce different notes when you slap the tube ends with flip
flops.  Of course, a garden hose is another cool musical instrument.
(Ok, I had to squeeze in just one more sound device.)

Becky Fox Matthews
Senior Educator/Special Projects Manager
Adventure Science Center
800 Ft. Negley Blvd.
Nashville, TN 37203
voice: 615-401-5073

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