The principle that describes the bournant force on objects submerged in fluids is known as Archimedes' Principle. This principle states that an object submerged in a fluid experiences an upward buoyant force equal to the weight of the fluid that it displaces. This concept explains why objects float or sink when placed in water and is fundamental in fields like physics and engineering. The principle applies to any fluid, not just water, and is instrumental in understanding phenomena related to fluid mechanics.