# Differences

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 phy131studiof17:lectures:chapter16 [2017/11/13 09:12]mdawber [A flaming tube] phy131studiof17:lectures:chapter16 [2017/11/13 09:12] (current)mdawber [Sonic Boom] Both sides previous revision Previous revision 2017/11/13 09:12 mdawber [Sonic Boom] 2017/11/13 09:12 mdawber [A flaming tube] 2017/11/03 11:35 mdawber [Open and closed pipes] 2017/11/03 11:32 mdawber [Open and closed pipes] 2017/08/04 13:41 external edit Next revision Previous revision 2017/11/13 09:12 mdawber [Sonic Boom] 2017/11/13 09:12 mdawber [A flaming tube] 2017/11/03 11:35 mdawber [Open and closed pipes] 2017/11/03 11:32 mdawber [Open and closed pipes] 2017/08/04 13:41 external edit Line 255: Line 255: More on sonic booms on [[http://​en.wikipedia.org/​wiki/​Sonic_boom|wikipedia]]. More on sonic booms on [[http://​en.wikipedia.org/​wiki/​Sonic_boom|wikipedia]]. + + ===== A flaming tube ===== + + + [[wp>​Rubens%27_Tube|Ruben'​s tube]], invented by Heinrich Rubens in 1905, like the Shive Wave Machine, is really only useful at demonstrating wave concepts. But it's very good at that! + + + {{flametube.png}} + + To understand why the flames are lower where the pressure varies more we need to realize that the velocity at which gas flows out is proportional to the square root of the pressure difference. This comes from Bernoulli'​s principle. + + It's worth noting that as the speed of sound is $v=\sqrt{\frac{B}{\rho}}$ and the density $\rho$ can be approximated as the propane pressure the standing wave frequencies depend on the propane pressure and will not be the same as the frequencies when the tube is just full of air at external pressure.