The reaction propagation is always from the ignition source to the media, so the ‘fire’ is always on the outside. Even if the inside is in the process of quickly becoming the outside.
By itself in a vacuum, no. Under gas pressure, when contacted by water it will react from the point of contact until all reactants are complete. I wouldn’t consider the reaction to be ‘fire’ though. At least not personally. Drop some hydrocarbons in the mix and you’ll get a fire as the oxygen produced gets something to react with.
Yes, that is how rockets get to space, for example. Earth’s atmo is ~21% Oxygen. So that is giving flames a boost. Careful not conflate “burn” with the presence of flames. In a vacuum, the flame could only exist briefly because there isnt the available Oxygen from the air. The reaction will (or might?) still happen, but without the oxygen to produce a flame.
BTW, this has been studied in microgravity aboard the ISS.
Air is on fire.
…
Unless the fire was in space I suppose - which can’t happen, so yeah, air is always on top of fire.
Edit: nope, I was wrong. Air is not always on top of fire :-P.
What about chemicals that create their own oxygen source when burning?
The reaction propagation is always from the ignition source to the media, so the ‘fire’ is always on the outside. Even if the inside is in the process of quickly becoming the outside.
No, I get that. Not why I asked the question.
If you have a compound like potassium super oxide chatch light in a vacuum, does it still burn because it has it’s own oxidizer?
By itself in a vacuum, no. Under gas pressure, when contacted by water it will react from the point of contact until all reactants are complete. I wouldn’t consider the reaction to be ‘fire’ though. At least not personally. Drop some hydrocarbons in the mix and you’ll get a fire as the oxygen produced gets something to react with.
Speaking from experience with Potassium Superoxide, once it goes up the flames are impressive in atmosphere.
I would absolutely expect that to be true. Generate enough oxygen, and damn near everything suddenly wants to be a gas that’s paired with it.
obligatory at this point:
https://www.science.org/content/blog-post/things-i-won-t-work-dioxygen-difluoride
Nah, foof doesn’t burn, it’s destroys everything around it with hatred for the universe that made it exist.
Yes, that is how rockets get to space, for example. Earth’s atmo is ~21% Oxygen. So that is giving flames a boost. Careful not conflate “burn” with the presence of flames. In a vacuum, the flame could only exist briefly because there isnt the available Oxygen from the air. The reaction will (or might?) still happen, but without the oxygen to produce a flame.
BTW, this has been studied in microgravity aboard the ISS.
Excellent point. I edited my comment to say that air is not always on top of fire:-D.