38. The Trick Behind an Ancient Drinking Prank
The Pythagorean Cup uses the basic principle of the siphon – same as that used to drain gas out of a car’s tank with a hose. The column inside the cup has a small hole at the bottom. The hole leads to an inverted U-shaped pathway inside the column. The pathway leads up from the hole at the bottom of the cup’s interior, to the top of the column, then loops back down to another hole at the base of the cup.
When wine is poured into the cup, the column inside fills to the same level as that of the wine in the cup. So long as the cup’s wine level does not reach the top of the U, the Pythagorean Cup functions like any other cup. However, if the wine level tops the column, and thus the U bend within it, the cup’s special effect takes over. Soon as wine tops the U bend and spills into the part of the column headed towards the hole at the base of the cup, the cup becomes a siphon, and begins to drain. Once the siphoning effect begins, it does not stop draining wine until the cup is empty.