Sunday, May 27, 2007

Speed of Sound

Speed of sound

The speed at which sound travels depends on the medium through which the waves are passing, and is often quoted as a fundamental property of the material. In general, the speed of sound is proportional to the square root of the ratio of the elastic modulus (stiffness) of the medium and its density. Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in air and other gases depends on temperature.

In air, the speed of sound is approximately 344 m/s, in water 1500 m/s and in a bar of steel 5000 m/s. The speed of sound is also slightly sensitive (to second order) to the sound amplitude, resulting in nonlinear propagation effects, such as the weak production of harmonics and the mixing of tones. (see parametric array).

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