Made By Manish Kumar, Murtaza Tunio and Minaam Abbas
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.
Step 1: What You Need
A Long Metal Tube
Stands for the Ruben's Tube
Amplifier Wire (PC to Amplifier)
Step 2: Dismantling the Amplifier
Step 3: Drilling Holes Into the Tube
Step 4: Creating Crocodile Clip Wires
Step 5: Closing the Tube
Step 6: Stands
Step 7: NCH Tone Generator
Step 8: Attaching the Gas Cylinder
Step 9: Attaching the Speaker
Step 10: Last Minute Adjustments
Drive Gain : 10
Drive Volume: 10
Clean Volume: 10
PS: The higher the frequency, the greater the amplitude needed.