• This simulator by T. Walsh shows the Doppler effect with adjustable speeds for both the source and the observer in one-dimensional motion. It displays the observer’s perceived wavelength and frequency. Watch what happens when the relative velocity exceeds the speed of sound!


This pair of animations by B. Surendranath are best used complementarily.

  • The first shows the Doppler effect with a fixed observer, but a variable frequency and speed for the moving source.

  • While the second compares the wavelength as measured from the two points.


  •  D. Russell has a page with a series of animations breaking down different cases of the Doppler effect, to compare motion below and above the speed of sound