The Archimedes' principle was named after Greek philosopher Archimedes.
The principle is closely related to buoyancy as you can see in the
Here is what Archimedes states:
Whether the object is partially submerged or not, the principle is still true.
For example, suppose you submerge a rock in water whose weight is 10 pounds and the water that is displaced has a weight of 4 pounds, what is the buoyant force?
Since the rock displaced 4 pounds of water and the buoyant force is equal to the weight of the liquid that the object displaces, the buoyant force is 4 pounds.
Notice that it is not the weight of the object that determine the buoyant force, but the weight of the displaced water. This situation is illustrated in the figure above.
The strength of the force beneath the rock that pushes the rock up is equal to 4 pounds.