Christian Doppler

Christian Andreas Doppler (November 29, 1803 - March 17, 1853) was an Austrian mathematician, most famous for the discovery of the Doppler effect which causes the frequency of a wave to apparently change as its source moves toward or away from you.

Resources:

http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Doppler.html - An online biography of Doppler

See also: Doppler effect