Pour enough of a drink to wet your whistle, but don't be greedy! This cup spills all of its contents on anyone who fills it too high. According to legend, it was invented over 2,500 years ago by the Greek philosopher Pythagoras to teach his students moderation in life.
When liquid in the cup is lower than the bend of the straw, it won't spill. As soon as the liquid is higher than the bend of the straw, the filled side of the straw will spill over the bend. The straw works as a siphon as gravity pulls the rest of the liquid in the cup through it and out the hole in the bottom. A toilet bowl also has a siphon and works the same way during a flush.
By: Angie Neer