We always thought it was magic but apparently we were wrong.
The good people at Brain Stuff solved the mystery behind petrol pumps using science and things and condensed it all down into one video that makes the whole thing seem very obvious after watching.
Now you're going to have to put up with a lot of "gas" instead of petrol because Americans refuse to call things by their proper name but trust us, it's worth it. Who knows, you may just impress someone with this knowledge someday.
Via YouTube