PURPOSE: To demonstrate dramatically standing waves in a tube.
DESCRIPTION: A loudspeaker in one end of a four-inch diameter galvanized iron tube creates standing waves in propane gas in the tube. The gas emerges out of a series of small holes in the top of the tube, forming a long line of flames when lit. Any sound resonant with the length of the tube can create standing waves in the gas which are readily visible as a pattern in the height of the flames. Both rhythm and frequency response can be seen nicely in music. An oscillator or a voice introduced using a microphone and amplifier provided with the demonstration can be used as simple sources for the loudspeaker.
REFERENCES: (PIRA 3D30.50)
EQUIPMENT: Flame tube with audio oscillator, microphone and amplifier, and audiocassette player with audiocassette, permanently assembled on rolling stand as photographed.
SETUP TIME: None.
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