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Revision as of 18:14, 23 January 2003 by CYD (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)The speed of sound waves through a given medium. Usually quoted in describing properties of substances, such as Sodium.
More commonly the term refers to the speed of sound in air. In this case the physical properties of the air, its pressure and humidity for instance, affect the speed. However due to the complex way that all of these factors are interrelated, the speed in fact varies linerarly with temperature. An approximate speed can be calculated from:
v = 331 + (0.6 T), where T is the temperature in degrees Celsius
The speed of sound is typically measured given a "standard atmosphere". Under these conditions the speed of sound is approximately 343 m/s, or 750 miles/hour.
In solids the speed of sound is given by:
v = (E / ρ), where E is Young's modulus and ρ is density.
Thus in steel the speed of sound is approximately 5100 m/s.
The speed of sound in water is of interest to those mapping the ocean floor. In saltwater, sound travels at about 1500 m/s and in freshwater 1435 m/s. These speeds vary due to pressure, depth, temperature, salinity and other factors.
See also Mach number.