Cao Chong

Cao Chong (196–208),courtesy name Cangshu, was a son of Cao Cao, a warlord who rose to power towards the end of the Han dynasty and laid the foundation of the state of Cao Wei in the Three Kingdoms period. A child prodigy, Cao Chong is best known for his ingenious method of weighing an elephant using the principle of buoyancy. He was considered by his father as a possible successor but died prematurely at the age of 12.

Family background

Cao Chong was the eldest son of Cao Cao and his concubine Lady Huan (環夫人). He had two younger brothers: Cao Ju (曹據) and Cao Yu. He was a child prodigy and already possessed the intelligence of an adult when he was around the age of five.

Principle of buoyancy

On one occasion, the southern warlord Sun Quan sent an elephant as a gift to Cao Cao. Cao Cao wanted to know the animal's weight so he asked his subordinates but no one could think of a method to measure the elephant's weight. Cao Chong said, "Place the elephant on a boat and mark the water level. Then replace the elephant with other objects until the boat is submerged to the same level. The weight of the elephant can be found by summing up the weights of all the objects." Cao Cao was delighted and he had Cao Chong's idea implemented.