The mesmerizing ripple tank

In this video a motor driven exciter is used to periodically tap on the water surface in a shallow tank. The waves that are thus generated refract the light rays that come from a lamp above, creating a pattern of shadow and light. This pattern is not observed on the bottom of the tank but rather reflected by a mirror to the ceiling. A variety of phenomena can studied in a ripple tank: 0:00 Preparations 1:49 Generation of circular waves (spherical waves in 3D) 2:38 Generation of linear waves (plane waves in 3D) 3:08 Superposition of wavelets according to Huygens' principle 4:14 Diffraction of a linear wave by an obstacle 5:06 Sigle slit experiment 5:44 Double slit experiment 7:05 Interference of two circular waves 9:00 Refraction of a wave (c is reduced in shallow water) 10:29 Doppler effect & Mach cone Tip: Hold the video to examine the wave pattern in detail. Tip: Use . and , for single frame forward and left/right for 5s forward.