What Is Hydrostatic Law?

Hydrostatic law is a principle that identifies the amount of pressure exerted at a specific point in a given area of fluid lying on top of a surface. It can also refer to the overall weight of this fluid on a surface.

Hydrostatic pressures describe the increasing amount of pressure that water exerts as it gets deeper. The French scientist Blaise Pascal wrote a principle relating to hydrostatic pressure that states that when one part of a body of water is pressurized, that pressure transmits throughout the entire body of water without diminishing. The formula for Pascal's hydrostatic principle is P = Patm+ Pg, where P equals pressure.

This principle is the basis for hydraulic systems and can be seen in action in hydraulic pump systems that place pressure on a column of water on one side in order to exert that force on another side of that column. For instance, if a u-shaped pipe has a valve that applies downward force on the left arm of the u and a moving plate on the u's right arm, pressure applied by the valve on the left will cause the plate to move on the right. Given enough force, this force can lift heavy loads, including cars and large boats.