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Horizontal Flame

  1. Feb 24, 2009 #1


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    I just lit a stick of incense. I observed that before the flame snuffed out, it consisted both of a vertical and a thinner horizontal flame. The horizontal flame was exactly perpendicular to the vertical one. It kept to a straight line and did not rise at all. Before I could photograph the flame, it went out.

    I found this bizarre, since I have never seen or heard of a horizontal flame, nor could think of anything that could cause a flame to behave in such way. I'm curious what mechanism could explain this phenomenon.
  2. jcsd
  3. Feb 24, 2009 #2


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    Science Advisor

    A flame is just burning gas in air. The heat causes the burning matter to decompose forming the gases that burn.

    So, what I think must've happened is that there was some cavity in the stick with a small hole in the side. The cavity filled up with combustion gases under pressure, which escaped through the hole and formed a sideways jet of burning gas. Voilá: A horizontal flame.
  4. Feb 24, 2009 #3
    That sounds a likely explanation alxm.Why not try an experiment NJV by making a cavity?
  5. Feb 24, 2009 #4


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    Thanks for the quick and helpful reply, that sounds illuminating.

    I'll try puncturing an incense stick with a needle and see what happens, but I'm not sure it will work. It's probably rather delicate.
  6. Feb 24, 2009 #5
    I see horizontal flames coming out of jet engines all the time... :wink:
  7. Feb 24, 2009 #6


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    If alxm is right, it might actually be similar to that. :)
  8. Feb 24, 2009 #7


    Staff: Mentor

    And welding torches.
  9. Feb 24, 2009 #8
    Were there any other factors that may have made the flame act the way it did?
  10. Feb 24, 2009 #9
    I could only see a horizontal flame being produced if there is a force pushing the flame horizontally, such as what redargon said with jet engines. this cavity would have to go vertically from the top then would curve horizontally out the side. then a force, such as a slight push of air, would push the flame out the side. This could absolutely work; but with my luck, would fail completely.
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