[ASLplease]

martin14 wrote:

I'll say the short one first.

the Co2 released from combustion will accumulate on the bottom
of the container, and slowly rise as the oxygen gets used up.

So the Co2 will hit the short candle first, and snuff it out.


Or, I'm full of shit

Fire Marshall Bill says to get on the floor when the house is burning down.

[Blue_Nose]

ASLplease wrote:

the flames will extinguish long before either candle burns out.

Obviously when I describe the candles going "out" I mean due to the cover and subsequent lack of oxygen.

People seem to think the CO2 produced will accumulate at the bottom, being heavier than oxygen - why does smoke rise, then?

[ASLplease]

Smoke", strictly speaking, consists of particles of ash carried on the hot are from burning. Since hot air is less dense than cold air, it rises as it is displaced by the heavier cold air. I suppose you could say that the "fluid" you are talking about is the cold air. Actually, with the particles of ash, the density is not a great deal less than that of cold air- smoke does not always rise. Depending on the circumstances, it can stay close to the ground.

You cannot have ordinary burning in vacuum- no oxygen. If you were to use a substance that contained its own oxygen, say sodium peroxide, the vapors that came off in vacuum would not rise.

http://www.physicsforums.com/showthread.php?t=221755