3B22.u1 - Gas Pipe or Rubens Flame Tube
Demonstrate standing waves due to the propagation of sound waves in a closed tube filled with gas.
InstructionsA five-foot long, one and a half-inch diameter pipe is closed at one end and has a polyethylene diaphragm and a horn driver across the other. The pipe is fed with natural gas which escapes from a row of small holes along the top edge of the pipe. When it is lit, a row of small flames forms. If the pipe is now driven at one of its natural frequencies, a standing wave is set up in the gas which varies the gas velocity/density and consequently varies the amount of gas being fed to the flames and is directly proportional to the relative position of the standing wave in the pipe to the exit holes of the gas. Thus, the flames no longer burn with the same length of flame, but with a sinusoidally modulated envelope.
DO NOT USE THE RADIO SHACK AMPLIFIER