Oxygen and Nitrogen make up a significant part of the atmosphere. Fire always stretches upwards, assuming no wind, leading me to believe it’s less dense than air. Oxygen is highly flammable. That should be everything fire needs to sustain itself while flying away into the sky.
In: Chemistry
Oxygen is not “flammable” but it *IS* an oxidizer, which means it makes any *existing* fire more intense.
And when you see a fire, you are actually seeing the fumes burning, not the actual wood or whatever. The heat from the fire causes the fuel to give off flammable gasses, those gasses burn, which increases the heat, which causes more gasses to be given off, in an endless circle until there is no more gasses to be had. In that process, it damages the wood or other fuel provider and reduces it to ash.
So the fire relies on those gasses to burn, and that’s why it stays firmly in place and doesn’t fly off into the sky.
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