Doppler effect

Article By:

Otten, Ernst Wilhelm Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Germany.

Last reviewed:November 2018

DOI:https://doi.org/10.1036/1097-8542.203400

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• Doppler effect, published February 2014:Download PDF Get Adobe Acrobat Reader

The change in the frequency of a wave observed at a receiver whenever the wave's source, the receiver, or the carrying medium of the wave is in motion relative to the other. The Doppler effect was predicted in 1842 CE by Austrian physicist Christian Doppler, and first verified for sound waves by Dutch chemist and meteorologist C. H. D. Buys-Ballot in 1845 from experiments conducted on a moving train. The Doppler effect for sound waves is now a commonplace experience: If one is passed by a fast car or a plane, the pitch of its noise is considerably higher during the vehicle's approach than during the receding (Fig. 1). The same phenomenon is observed if the source is at rest and the receiver is passing it. An optical Doppler effect was first observed as a shift of spectral lines by German physicist Johannes Stark in 1905 in experiments involving high-velocity canal rays produced in a cathode-ray tube. See also: Cathode-ray tube; Light; Optics; Pitch; Sound

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