A device that demonstrates the Doppler effect
Emits sound when a button is pushed. The device is attached to a cord and swung in a circular motion, producing the Doppler effect. Your students will immediately hear changes in pitch. Once the button is pushed, it continues to make the sound until the button is pushed again. It can be turned on and off without taking it apart. It comes housed in a plastic case with a screw-eye bolted securely into the case.