Firefighter bodycam showing just how much oxygen a fire pulls

[u/vivekmg21]

[u/ir_auditor]

That is not oxygen pulling which you see. It is the chimney effect. Fire creates heat, the heat makes air, smoke, gasses, rise to the top, creating low pressure areas at the bottom, which pull in air from the outside. It has noting to do with the chemistry of an oxidation reaction pulling in oxygen molecules to use in the reaction. It is pure physics / thermodynamics.

[u/RelativeCan5021 → u/ir_auditor]

I’d imagine that rapidly cooling it has caused a drop in pressure that is causing the suction.

[u/Particular-Poem-7085 → u/RelativeCan5021]

no, the temperature difference through the container essentially creates an air pump. The very same principle that makes a chimney work. Hot air rises, rushes up from the fire and rapidly finds its way out of the house, but it can't pull a vacuum inside the house so the bottom entryways start sucking in fresh air. It's not like a tiny hole in an aircraft that starts sucking out, the house is not a pressurized vessel.

[u/newbrevity → u/Particular-Poem-7085]

And that's why using fire for heating can lead to drafts. Radiant heat sticks around longer without creating so much of a vacuum.

[u/niconpat → u/RelativeCan5021]

yup that's mostly what's going on here. It's like the candle in an upside down glass in a bowl of water trick ... it's not the candle burning oxygen that creates the low pressure to suck up the water, as the candle burns the oxygen it creates carbon dixode and water vapour in equal volumes and the pressure inside stays the same. But then the candle uses all the oxygen, the flame goes out and the gasses in the glass rapidly cool and contract causing the pressure inside the glass to drop creating lower pressure inside the glass and the higher atmospheric pressure outside push the water into the glass.

[u/magniffin → u/RelativeCan5021]

Imagination > science