Investigate the Doppler effect. The Doppler effect describes the shift in frequency of a wave that is produced by the motion of either the wave source or the observer of the wave (or both). In this simulation, you can explore the change in the wave that is produced by source and/or observer motion, and you can even view what the situation looks like from the perspective of the medium (the standard reference frame), the source, or the observer.

Requirements:
* Java

The license of this software is Freeware, you can free download and free use this calculator software.