The Physics of the Flush

Evidently, toilet technology is improving all the time, but certain laws of physics continue to govern the process:

Flushing toilets is all about physics and stored potential energy. The water that is at rest in the tank just before the flush has the ability to do work because of its weight and the pull of gravity once the flush handle is activated. For the flush to be complete, this water needs to enter the bowl as rapidly as possible and encounter as little friction as possible as it leaves the bowl on its way to the drain. You can buy toilets that have enormous three and one-quarter inch flush valve openings at the bottom of the tank. These same toilets have fully-glazed trapways so the water and waste slips through the toilet with minimal friction.

Toilets Just Keep Getting Better [Ask the Builder via Apartment Therapy]