The behavior of an object submerged in a fluid is governed by Archimedes' Principle. Archimedes (a greek mathematician) determined that a body which is completely or partially submerged in a fluid experiences an upward force called the Buoyant Force, B , which is equal in magnitude to the weight of the fluid displaced by the object. This principle can be used to explain why ships, loaded with millions of kilograms of cargo, are able to float.