Retrograde Motion Illusion for an Electric Fan
Wolfram Demonstrations Project · 2008
This Demonstration shows the rotation of an electric fan in slow motion—by about a factor of 10—for computer display compatibility. The fan rotates clockwise. A conventional incandescent light source is somewhat stroboscopic, due to the 60-cycle alternating current powering it.Certain combinations of rotation rate and strobe frequency produce the illusion of retrograde motion, with the