A length of pipe is perforated along the top and sealed at both ends - one seal is attached to a small speaker or frequency generator, the other to a supply of a flammable gas (propane tank).
The pipe is filled with the gas, and the gas leaking from the perforations is lit. When the speaker is turned on, the pressure changes caused by the sound waves will cause the flames to heighten in some areas and to lower in others. If a constant frequency is used, it is possible to determine the wavelength by simply measuring with a ruler.
August Kundt, in 1866, demonstrated an acoustical standing wave by placing seeds of lycopodium or cork dust in a tube. When a sound was made in the tube, the material inside lined up in nodes and antinodes in line with the oscillation of the wave, creating a standing wave. Later that century, Behn showed that small flames could be used as sensitive indicators of pressure.
Finally, in 1905, using these two important discoveries, Heinrich Rubens, whom this experiment is named after, took a 4-metre-long tube and drilled 200 small holes into it at 2 centimeter intervals, and filled it with a flammable gas. After lighting the gas (whose flames all rose to near-equal heights), he noted that a sound produced at one end of the tube would create a standing wave, equivalent to the wavelength of the sound being made.
8 Responses to “Rubins’ Tube”rss
Futon-Matt, on December 14th, 2007, said:
That is so cool, I wish I had the guts to actually try it myself. :)
Matt
Matt Heller, on December 21st, 2007, said:
Great find
dulloq, on December 24th, 2007, said:
Really cool i never saw something like that!!!!
Edward, on January 5th, 2008, said:
Cool dude 1st time see something like that
chriz, on January 11th, 2008, said:
beatiful i love it
sendor, on January 13th, 2008, said:
cool its really something new, never seen bevor
gurlic, on January 18th, 2008, said:
i would like to do it myself too..
franzis, on January 19th, 2008, said:
great stuff where did you find it?
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