This explains how the siphon works to keep the bowl at the same level and to create the force of a "flush". Until I saw a toilet that had the siphon shape visibly exposed on the outside, I don't think I ever thought question how it worked. Once I saw the shape, I immediately thought about it working like a siphon I'd used to pull gas out of my car. For people who have never seen a toilet with the siphon shape exposed, they'd probably have to have siphon experience in some other area to make the leap, or I think how the bowl stays full and flushes would just naturally stay a mystery. Believing that it all happens in the tank might also be enough of an explanation for most to stop thinking about it.
