How is sound produced?

For sound to occur you need a vibrating source and a medium, and to detect it, you need a receiver.

There are many natural vibrating sources — vocal cords, stretched strings, reeds — but to create vibration there must be a certain amount of surface tension in the vibrating body.

To reach the receiver, the vibrations need a medium of transmission such as air or water.

Vibrations from the sound source disturb molecules in the medium. The molecules move at the same rate as the sound source. As the vibration travels through the medium each molecule hits another and returns to its original position. Regions of the medium become alternately more dense and less dense. The variation in pressure in the medium is sensed by a receiver such as the human ear or recording device and is called a sound wave.

Flow of longitudinal sound waves

What makes some sounds musical? 

Major funding for Rough Science was provided by the National Science Foundation. Corporate funding was provided by Subaru.

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