A burning cigarette is tossed into a bowl of 87 octane gasoline. A) BOOM or B) extinguished ?

Question

please.. please... nobody experiment before answering!

Question is based on a scene I saw in a movie. Guy drops a cig in a car's gas tank and it explodes. I started thinking Nahhhh... needs a spark or an open flame to make that happen

Answer 1

Extinguished.

For full information on this read the last edition of New Scientist, they have a large article on new discoveries in arson research.

One of them is that a cigarette thrown into petrol/gasoline doesn't stay hot for long enough to cause combustion.

Answer 2

I am not 100% sure, but I would suspect A) Boom. My reasoning as follows.

A lit cigarette, when you aren't actually sucking on it, has a temperature of 400-580 C. Gasoline's autoignition temperature is 260 to 460 C. Thus, if the gasoline came in contact with the cigarette, it could ignite without the presence of a spark or open flame.

That said, it also seems possible to me that there's some wiggle room... I'm not 100% sure that the temperature I found for a lit cigarette is correct, for example. And if your cigarette was burning cooler or had a lot of ash buildup around it you might be able to snuff it before it started the combustion reaction. And lastly if it were a hot day you would have more vapor above the gas surface, and you could light this vapor off pretty easily.

Answer 3

if the bowl is in a protected area with no wind, it is just likely the fumes above the gasoline will ignite
but it you have the bowl outside with wind and the wind is moving the fumes away from the gasoline, it is most likely to be extinguished...
that's why it is better in this way to get into a car accident with a full tank of gas... because the partial tank of gas has those fumes that will ignite, ...yes if the tank is ruptured and the gasoline spills onto something hot it will explode...( or is it the fumes emanating from the fuel??? that starts the fire and the gas provides the fuel for the fire?)
good luck
smile..

Answer 4

When I was young, i.e. like 20 years ago, some friends and I throw around five cigarettes into a one-gallon gasoline bottle and nothing happen. They get wet and turn off immediately. I suppose the same happens in a gas tank.
Somehow the gas may burn, but I can´t find any reason for it to explode.

Answer 5

My guess would be neither. I'm thinking that throwing it in a bowl would make a nice smelly fire.

But - throwing one into a car gas tank is different. That's a limited oxygen environment. The most likely result would be B) extinguished.

Cigarettes have plenty of sparks. Brush fires start every year in the hills above Eagle Rock, Los Angeles California, because some stupid goofus chucks a lit cigarette butt out his car window on the 134 freeway.

Answer 6

It all depends on oxygen. If you drop a match into a tank of gasoline and leave the lid open, the only thing that will happen is the top of the gas will start on fire, but no explosion due to there being only oxygen on top of the gas, not in it. But if you dropped it into a car's gas tank and closed the lid, assuming there was a good supply of oxygen in the air in the tank, enough pressure could build up in order to cause the explosion you so desire. Also, gas will evaporate into the air which would allow an ignition of the gas, but it will still only act as described above.

Answer 7

Usually A, but if the gasoline is below the FP (flash point) for gasoline, then there will be no Boom or fire.

It's possible, that the cigarette could get from the region of air around the gasoline which was too low a concentration to burn into the region which was too rich to burn, without igniting the region in between, but I'd not wanna be standing close enough to find out.

Answer 8

Well you're secondary comments seem right, a "burning cigarette" is just about smouldering, not an open flame. However, if you just took a puff on it and there was vapor build up above the liquid and gasoline does evaporate and cause vapor build up, maybe boom. Otherwise, i vote extinguish.

Answer 9

I go with extinguish unless it hits something before hand and gives off a spark. Also, it's the fumes that will ignite before it ever hits the gas but i would still go with B.

Answer 10

B-extinguish