We filled a graduated cylinder with Ever Clear and let it overflow. Then we lit the liquid on fire. To our surprise the flame started running around the base of the cylinder. Why does this happen?


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    $\begingroup$ Very curious. Too bad the video isn't embedded, but it's cool. $\endgroup$ Apr 27 '16 at 15:55
  • $\begingroup$ Cross-posted to Physics SE as well. $\endgroup$
    – Jon Custer
    Apr 27 '16 at 16:49
  • $\begingroup$ I have removed it from Physics SE $\endgroup$
    – Max00355
    Apr 27 '16 at 21:37
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    $\begingroup$ I can't decide if I can see the cylinder rocking slightly or not? Possibly the unstable cylinder was set in motion by the combustion and the bright flame is on the lifted edge where more oxygen can get to the fuel. $\endgroup$ Apr 27 '16 at 22:31

A flame is a dynamic phenomenon, using up fuel and oxygen in places and driven by convection and diffusion. Flames are sensitive to factors such as external sound, and can be used to measure frequency and waveform with a Rubens tube.

Under micro-gravity, flames burn quite differently, due to the lack of convection.

So though not a specific answer to your questions, I assume that oxygen is being used up rapidly in one spot, and the flame front moves along as convection brings in fresh oxygen. You could test this hypothesis by piping in just a little air in one spot on the "ring of fire" to see if it stabilizes the flame there.

Thanks for sharing that interesting video!


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