the scientific rule which explains that an object in a liquid is kept up by a force which is equal to the weight of the liquid that the object displaces. Law of buoyancy, discovered by Archimedes, which states that any object that is completely or partially submerged in a fluid at rest is acted on by an upward, or buoyant, force. The magnitude of this force is equal to the weight of the fluid displaced by the object. The volume of fluid displaced is equal to the volume of the portion of the object submerged