The water overflowed when Archimedes jumped in and he knew that there is a relationship between his weight and the volume of the water
Density=mass x volume Buoyancy= (density of object - density of fluid) x (volume of displaced fluid)
The conclusion of the Archimedes principle is simply that the upward buoyant force that is experienced by a body immersed in a fluid, is equivalent to the weight of the fluid that the body displaces. This allows the volume of an object to be measured by measuring the volume of liquid it displaces after submerging. For any immersed object, the volume of the submerged portions equals the volume of fluid it displaces.
Legend says that Archimedes discovered the principle of displacement while stepping into a full bath. He realized that the water that ran over equaled in volume the submerged part of his body. Through further experiments, he deduced the above mentioned Archimedes' principle.
Archimedes made a variety of advances including volume and buoyancy measurements along with mathematics that define the size of a cylinder using a sphere. He also helped to make a lever more useful in farming.
He discovered that you have to find the volume, mass, and density of something
How? With his brain! That's how he answered it
measure and calculate or find displacement with Archimedes principal
He discovered the method to calculate the volume of a irregular object (rock).
apply Archimedes principle
he find that the water was risen where he stared to put the person in.
Archimedes took a bowl full of water of known volume and then dipped the irregular shape body. Amount of water fall down is measured and is the volume of that body.
Water displacement is used to find the volume of irregular solids as discovered by Archimedes