Wednesday, January 28, 2015

Waldorf Homeschool: Seventh Grade Physics — Sound II

As part of our unit on sound we made some "toys." The first is a bull roarer. It is essentially a can with a string run through a hole in the bottom of the can. The other end of the string is tied loosely around a stick. (or a wooden clothespin, as in our experiment.) You whip the can around overhead in a circle. The string rubs on the stick causing vibrations. The vibrations travel down the string to the can which amplifies the sound.

The second noise maker is called a lions roar. That is a flat piece of wood with a hole drilled in one end. a string is tied through the hole. Again you whip this about in a circle and the piece of wood vibrates in the air causing a "lion's roar."

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