Quinchke's Interference Tube
Demonstrate How Two Sounds Cancel Each Other Out When Added Together
In this acoustics experiment, two Y-shaped glass tubes, each with different length length arms, are connected by two rubber tubes. Hold a struck tuning fork at the end of one tube and the waves flow down the tube to the Y where they divide. However, this apparatus makers the waves in one fork of the Y travel half a wavelength farther than the waves in the waves in the other fork. When the waves meet at the other end, they're in opposite phase to each other, so they cancel each other out. This results in no sound at all. Disconnect one of the rubber tubes and the sound reappears. Requires a 512Hz tuning fork. Length when set up: 38cm.