The accelerated oxidation of a high level of O2 creates heat in the chemical reaction itself. The accumulation of heat at a grater rate than it is capable of dissipating it is the source of heat that causes the ignition. It does not require an outside source to provide ignition as it does it by itself.
Agreed. I didn't mean to suggest that they had to be independent. That said, there has to be some source of heat to raise the fuel to it's ignition point.
They did not do that experiment in an elevated O2 environment so It doesn't really apply here. That experiment could have drastically different results if it were preformed in a high O2 environment.
Agreed, but the physics don't change. It's possible that in 100% O2 the cigarette could burn hot enough and fast enough to ignite the gasoline, however.
Concerning the Mythbusters episode, I'll have to look that up. But there is a concept of Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL) for any gaseous hydrocardon or material. The LEL is the lower limit below which the vapor will not ignite, as there is not enough fuel to burn. The LEL is the limit above which there is too much fuel and not enoughoxygen in the mixture to have
We're starting to confuse two different things here. "Explosion" vs. "Burn." The lit cigarette dropped into the toilet of gasoline doesn't set it on fire because the cigarette burns at a temperature below the ignition point of the fuel. True enough, if the environment was 100% O2 plus the fuel, it's possible that the tobacco/paper mix could have reacted quickly enough to hit the ignition point of the gasoline. Hella unlikely scenario, but I suppose it's possible.
Under these conditions, titanium will "spontaneously combust". That means it will burst into flames even when nobody "lights it". Why? Because of the oxidation. Oxidation causes heat and in some cases, like described above, the oxidation creates so much *intrinsic* heat that the related chemical reactions are self-propagating.
Agreed, but it is VERY difficult to make this happen. We tried this in my senior chemistry class for weeks. Oxidation doesn't produce very much heat.
Some things will simply burst into flames at room temperature if there is enough O2 and the right conditions available..... that's a simple fact.
Agree again. Those "right condition" must include some source of heat. Be it a spark, a flame, or even perfect conditions for combustion due to oxidation.
a combustion occured INSIDE of the bottle that then subsequently ruptured
If the cylinder contained 100% O2 then this would be impossible. O2 doesn't explode or even burn. Any welder can tell you this with an acetylene torch. You cannot turn on the O2 alone and spark a flame on the end of the torch. It'll never light without a source of fuel.
aluminum burns very hot and is used in pyrotechnics(fireworks), and in thermite.
True, but you're describing aluminum in a very fine powder form, not something as rigid as a tank wall.
8. oils on a concrete floor can combust when a stream of high pressure oxygen hit them.
No, it can't. There absolutely MUST be some ignition source. Just hitting oil with O2 will not cause combustion.
Certain materials can spontaneously combust in the presence of pure oxygen, like perhaps the clothing on his back became saturated with oxygen, if not spontaenous, an already existing heat source cause them to ignite, since its likely not all the oxygen was consumed in the initial blast.
True but you most certainly would not make clothing out of any of these materials. They're highly volatile, even in plain Air.
Gang, please understand what I'm trying to accomplish here. There is a lot of misinformation in this thread probably due to silly Hollywood effects. We all agree that there was an explosion and a subsequent fire. It's the causes that are still a mystery.
I can only reason that the tank ruptured on impact but wow, that sure seems unlikely. I've seen dozens of Scuba tanks dropped, hit, knocked over, it happens all the time. They don't rupture. Again, Mythbusters tried this over and over. They repeatedly shot an AL80 with a rifle from various angles and it never did rupture. If it did, I can see how the explosive decompression of the tank could have wrecked his hand and done the explosive damage to the garage. Then the fire started due to the increased amount of O2 in the space.
-Charles
but most clothing is combustable, 5 to 10 times more so in pure oxygen. Synthetics sticking to you as they melted.
