Doppler effect

   Also known as Doppler shift. Both eponyms refer to the Austrian mathematician and physicist Christian Andreas Doppler (1803-1853), who first described the effect in or shortly before 1842. In perceptual neuroscience, they are used to denote an * auditory illusion consisting of a change in frequency of a sound, as perceived by an observer moving relative to the source of the sound. In everyday life the Doppler effect is experienced when a motor vehicle approaches an observer, and then passes and recedes. As compared to the emitted frequency of the sound, the perceived frequency is increased during the approach, identical at the instant of passing by, and decreased during the recession. Doppler's original description had a bearing on the light waves emitted by binary stars. The application of his discovery to sound waves was published in 1845 by the Dutch chemist and meteorologist Christophorus Henricus Diedericus Buys Ballot (1817-1890).

   References

   Doppler, C.A.D. (1842). Über das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels. Versuch einer das Bradley'sche Aberrations-Theorem als integrirenden Theil in sich schliessenden allgemeineren Theorie.Prag: Verlag der Königl. Böhm, Gesellschaft der Wissenschaften.

   Jonkman, E.J. (1980). Doppler research in the nineteenth century. Ultrasound in Medicine & Biology, 6, 1-5.