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Speed of Sound

The idea that there is a speed of sound and that it can be measured is a major achievement. A possible explanation to this discovery lies in the fact that mother nature exhibits in every thunder storm the difference between the speed of light and the speed of sound. There is no clear evidence as to who came up with this concept, but some attribute it to Galileo Galilei: 166x. Galileo, an Italian scientist, was one of the earliest contributors to our understanding of sound. Dealing with the difference between the two speeds (light, sound) was a major part of Galileo's work. However, once there was a realization that sound can be measured, people found that sound travels in different speeds through different mediums. The early approach to the speed of sound was by the measuring of the speed of sound.

Other milestones in the speed of sound understanding development were by Leonardo Da Vinci, who discovered that sound travels in waves (1500). Marin Mersenne was the first to measure the speed of sound in air (1640). Robert Boyle discovered that sound waves must travel in a medium (1660) and this lead to the concept that sound is a pressure change. Newton was the first to formulate a relationship between the speed of sound in gases by relating the density and compressibility in a medium (by assuming isothermal process). Newton's equation is missing the heat ratio, (late 1660's). Maxwell was the first to derive the speed of sound for gas as $c=\sqrt{kRT}$ from particles (statistical) mechanics. Therefore some referred to coefficient $\sqrt{k}$ as Maxwell's coefficient.

Next: The shock wave puzzle Up: Early Developments Previous: Early Developments Index

Created by:Genick Bar-Meir, Ph.D.
On: 2007-11-21

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