Answer to Question #164342 in Optics for Sanamtha

Question

Describe a simple laboratory demonstration of the Doppler Effect for sound waves.

Answer 1

Sound waves are transverse waves, but their speed is too high to notice Doppler effect in a laboratory. Thus, we need slower transverse waves, which can be obtained with a vibrator put in water. As it is not moving, circular waves start moving from the vibrator outwards along the water surface. When we move the vibrator in the plane of the water surface, we notice that the distance between waves shrinks in front of the vibrator and increases behind the vibrator. Thus, wavelength indeed changes as the source of transverse waves moves.