6D40.60 - Optical Doppler Radar
See also 1H10.35 in Mechanics
Attach the magnet to the blackboard or metal wall. Align the laser beam so that it is bounced back into the laser. Place the beam splitter in front of the laser and put the reflected beam onto the photocell. Turn up the amplifier and then press on the wall or the table holding the apparatus. A squeal should emit from the amplifier speaker as the wall or table flexes.
An simple version of this demo is to just shoot the laser beam directly into the photocell that is connected to the amplifier/speaker. Place a microscope slide in the beam between the laser and the photocell. As you rotate the microscope slide a "whine" will be heard from the speaker.
- T. D. Nichols, D. C. Harrison, and S. S. Alpert, "Simple Laboratory Demonstration of the Doppler Shift of Laser Light", AJP, Vol. 53, #7, July 1985, p. 657.
- François Remy, "Doppler Effect: An Optical Experiment", AJP, Vol. 46, #7, July 1978, p. 763.
- T. Kallard, "The Optical Doppler Radar", Exploring Laser Light, p. 174.
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