All liquids in a state of equilibrium exert energy on the materials it comes in contact with. There are two forms, hydrostatic load or outside forces. When used against a level surface, the liquid exerts equal force against all points of that surface. When an subject is thoroughly immersed in a liquid, vertical force is applied to the object at each point. These vertical forces are buoyancy, and the concept Extra resources by itself is more fully defined by Archimedesâ€™principle. Liquid acted on by hydrostatic force is then subject to hydrostatic pressure at the point of contact. A cityâ€™s water supply system, fountains, and artesian wells are all good examples of the application of these principles on containers.