The Pythagoras cup or the magical Krishna cup is a device in which when any liquid is poured beyond the desired point, the entire cup drains out all its contents through base because of the Siphon effect.
The cup is named after a famous scientist Pythagoras. He created it as a practical joke device. The idea is, If a person feels greedy and overfills the cup with wine then the entire cup of wine will spill on him.
This cup is also known as greedy cup, the cup of justice or the Magical Krishna cup.
Many people get curious that why it is known as Magical Krishna cup. There is an interesting story behind this.
Magical Krishna cup
About 5000 years ago when lord Krishna was born and his uncle ( Kansa ) wanted to kill him immediately, in order to save his own life. Lord Krishna was eighth avatar of load Vishnu. He was born to kill Kansa and save people from his cruel actions. To wait for the right time and to fulfil some more intensions, Baby Krishna was secretly taken away by is father ( Vasudeva ) across the river Yamuna to Mathura. Actually Lord Krishna’s father Vasudeva and mother Devki were imprisoned by his uncle Kansa. Krishna with his magic made all soldiers sleep and opened the prison. When his father was crossing the river with baby Krishna on his head, the water level began rising until it touched the feet of lord Krishna. As soon as the water touched the feet of lord Krishna it completely drained out and became dry so the father caring lord Krishna could easily cross the river safely. Later Goddess Yamuna revealed that she desperately wanted to touch lord Krishna’s feet and get his blessings.
Magical Krishna cup or the magic jars are still found in museums and ancient Hindu temples with idol of lord Krishna placed at centre of it, at a certain height. When the cup is filled with water, it keeps rising until it touches lord Krishna idol’s feet and then the entire water drains out. It is believed that the very first magic jar was created at the time of lord Krishna who lived about 5000 years ago whereas Pythagoras designed it about 2500 years ago.
Magical Krishna cup or the Pythagoras cup has a very simple structure and it is very easy to make. We just need a U shaped tube or U bent straw fixed inside the cup like container such that one end of the tube touches the internal base of the container and the other end opens outside the cup passing through the leakproof hole in the centre of container.