 Ever wonder why normally heavy objects seem to weigh less underwater? It's due to the buoyancy. Even a heavy metal weight becomes lighter due to the buoyancy properties of water. When an object is submerged into a liquid, a buoyant force is simultaneously pushing it upward. When an object is buoyed up, its apparent weight is equal to its actual weight, minus the weight of the liquid that it has displaced. This relationship is known as the Archimedes Principle. Archimedes Principle was discovered by Archimedes of Syracuse in the 3rd century BC when he sat in the bathtub and noticed the water rising around him. The principle states that the upward buoyant force exerted on any object submerged in a liquid is equal to the weight of the fluid that it displaces. If we submerge a 25 kilogram weight and it displaces 20 kilograms of water, then its apparent weight underwater is 5 kilograms, the original weight minus the weight of the displaced water. So the next time your friend is hoping to impress you with his feets of strength lifting a large weight while underwater, explain to him the Archimedes Principle and the buoyant properties of water.