Postprint version. Published in American Journal of Physics, Volume 69, Issue 12, December 1, 2001, pages 1231-1236. This article may be found online at http://dx.doi.org/10.1119/1.1405503.
Copyright © 2001 American Association of Physics Teachers. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Association of Physics Teachers.
NOTE: At the time of publication, the author Thomas Bensky was not yet affiliated with Cal Poly.
An approach to experimentally measuring the speed of a moving object by direct application of the Doppler effect for sound is discussed. The method presented here uses a Windows computer and sound card to record Doppler shifted sound from a moving source. This sound card approach allows for direct acquisition of Doppler shifted sound intensity as a function of time, affording much analytical and pedagogical freedom in undergraduate lab instruction. In addition, the acquisition of such data allows for the experimental study of not only constant velocity sound sources, but of accelerated sound sources as well.