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The Ruben's Tube is a physics experiment demonstrating a standing wave. It demonstrates the link between sound pressure and sound waves.
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. If a suitable constant frequency is used, a standing wave can form within the tube. When the speaker is turned on, the standing wave will create points with oscillating (higher and lower) pressure and points with constant pressure (pressure nodes) along the tube. Where there is oscillating pressure due to the sound waves, less gas will escape from the perforations in the tube, and the flames will be lower at those points. At the pressure nodes, the flames are higher. At the end of the tube gas molecule velocity is zero and oscillating pressure is maximal, thus low flames are observed. It is possible to determine the wavelength from the flame minima and maxima by simply measuring with a ruler.
Since the time averaged pressure is equal at all points of the tube, it is not straightforward to explain the different flame heights. The flame height is proportional to the gas flow as shown in the figure. Based on Bernoulli's principle, the gas flow is proportional to the square root of the pressure difference between the inside and outside of the tube. This is shown in the figure for a tube without standing sound wave. Based on this argument, the flame height depends non-linearly on the local, time-dependent pressure. The time average of the flow is reduced at the points with oscillating pressure and thus flames are lower.
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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. If a suitable constant frequency is used, a standing wave can form within the tube. When the speaker is turned on, the standing wave will create points with oscillating (higher and lower) pressure and points with constant pressure (pressure nodes) along the tube. Where there is oscillating pressure due to the sound waves, less gas will escape from the perforations in the tube, and the flames will be lower at those points. At the pressure nodes, the flames are higher. At the end of the tube gas molecule velocity is zero and oscillating pressure is maximal, thus low flames are observed. It is possible to determine the wavelength from the flame minima and maxima by simply measuring with a ruler.
Since the time averaged pressure is equal at all points of the tube, it is not straightforward to explain the different flame heights. The flame height is proportional to the gas flow as shown in the figure. Based on Bernoulli's principle, the gas flow is proportional to the square root of the pressure difference between the inside and outside of the tube. This is shown in the figure for a tube without standing sound wave. Based on this argument, the flame height depends non-linearly on the local, time-dependent pressure. The time average of the flow is reduced at the points with oscillating pressure and thus flames are lower.
Please Rate My Instructable and vote for me in the Epilogs Challenge. Thank you :)
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Signing UpStep 1What You Need
Materials:
Drilling Machine
A Long Metal Tube
Gas Pipe
Gas Cylinder
Speaker Wire
Guitar Amplifier
Crocodile Clips
Stands for the Ruben's Tube
Wire Strippers
Screw Drivers
Scissors
Amplifier Wire (PC to Amplifier)
Lighter
Drilling Machine
A Long Metal Tube
Gas Pipe
Gas Cylinder
Speaker Wire
Guitar Amplifier
Crocodile Clips
Stands for the Ruben's Tube
Wire Strippers
Screw Drivers
Scissors
Amplifier Wire (PC to Amplifier)
Lighter
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1) one end should be welded shut. do you want the card board to burn and shoot gas from the end when the card board fails.
2) You do not use hose clamps on flame effects feeding gas. use propane lines with NPT threads and threaded fittings on the tube or swaglok fittings.
3) The end that the speaker is placed should not use latex gloves or anything else with a low melting point. It needs to be a high temp rubber. Not doing these things can result in a catastrophic failure of large amounts of gas coming out of the end and even having a flaming propane hose whipping around in the air. Taking my steps would also help make it NFPA 160 compliant for safety to be used in front of an audience. NFPA 160 is the code that covers fire in front of an audience that governments around the world use to regulate fire in front of an audience. Don't put your self and other innocent bystanders at risk
I am a professional Flame effect artist.
www.trailertrashman.com
I can see that touching the speaker cone to a rubber membrane would transfer sound energy rather easily but if covered with cardboard it would be pretty stiff.
If you are using the balloon as the transfer media, does the gas pressure inflate the balloon?
And another question: what size drill bit did you use? Do you have any guess as to what the effect of larger or smaller holes may have?
Thanks.
2) Yes the gas pressure does inflate the balloon that's why I covered it with like 5 balloons and then reinforced it with tape. :)
3) Well, i am not certainly sure if the size of the drill bit makes a difference, but I do know that gas stoves have small holes so it is advisable to have small holes otherwise the gas might escape quicker. :)