I already posted one of the sound experiments we did recently, but our experiment today, was just different enough, and worked so well, I thought I'd share it, too. We found it in Jim Wiese's Head to Toe Science, but I've seen it mentioned, with slight variations, in other books, as well.
All you need is some plastic wrap, a toilet paper tube, a rubber band, a flashlight, and a darkened room.
Pull the plastic wrap, tightly, over one end of the toilet paper tube, and secure it with the rubber band. You want it to be as smooth, and tight, as possible.
In a darkened room, hold the open end of the tube in front of your mouth, with the covered end pointing at a wall, or smooth surface.
Shine the flashlight on the plastic wrap, so it reflects back to the wall.
Then, talk into tube, and watch as the light reflection on the wall vibrates.
We talked high, and low, and the vibrations changed from small and fast, to slow and large. We also clapped in front, but a little back, from the tube, and rang a small bell into it, so we could see, that it was not our breath that was vibrating the plastic (though I'm sure it was, too), but the actual vibrations of sound waves.
The resulting vibrations were so much clearer, and more impressive than I thought they'd be. There was a definite "Wow!" factor for the children - one of those, "Look at that!" kind of moments...
...that make it great to be a homeschooler.