Ever wonder how the gas pump nozzle shuts itself off when the gas tank in your car is full? Yeah, I never have either. Until I saw this article on MSN. I guess I just never thought about it. It's relatively simple though, and pretty impressive considering the 'technology' behind it has been around for 50 years. Impressive because there really wasn't technology back then.
This article also answers some of the other questions you've come up with while driving but never thought to actually ask. Anyone have anything that wasn't covered in the article?