Question has been bothering me a while.
When putting fuel at any gas station, when the tank is almost full, the pump just stops and makes a 'THUNK' noise.
I was wondering... how the hell does the pump knows the tank is almost full? There doesnt seem to be a probe that when the fuel touches it it stops the pump, and you can always put a little bit more and be ok...
So how does the pump know how to stop itself?