laz1b01

laz1b01 t1_ixtvigc wrote

Reply to ELI5: Why do you have to turn your car off when you fill up your tank? by logan0921

You ever watch Die Hard (or similar movies) where there's a plane with a leaking fuel taking off, then Bruce Willis ignites the line of leaking gas, and you see it slowly going up in flames in a straight line towards the plane?

Yea...spoiler alert, it doesn't really happen. I learned the hard way. Gas is highly combustible, so it nearly goes up in flames in an instant, so the scene in movies is for cinematic effects.

So when you put gas in a car it goes to the gas tank. From the gas tank, goes to the engine where it's burned to make the car move. Fortunately, safety laws and design have put precautions to ensure that gas within the tank is not burned. But just because it's designed for safety, doesn't mean it's 100% full proof cause of design flaws. So you turning off your car is to ensure the burned gas in the engine doesn't reach the tank (which eventually reaches the gas pump)....because if it does reach it, it'll burn instantly.

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