Calculating Pressure A liquid at rest in a flask pushes against the walls and floor of the flask, creating a pressure on the container and on the surrounding fluid. The pressure exerted by an incompressible fluid at rest (hydrostatic pressure) is the same everywhere at a given height and depends only on the weight of the fluid above the point of interest. The pressure difference ( P ) between any two heights is calculated from the fluid density (), the acceleration of gravity (g = 9.8 m/s2), and the height ( Th) of the column of fluid between the points of interest: P = gh Many times, a container's opening is at atmospheric pressure. In this case, the pressure at a specific depth within the fluid is often reported as gauge pressure. The gauge pressure is the difference in pressure between atmospheric pressure and fluid pressure: Pguage = gh when h is the distance below the fluid's surface. The sum of the atmospheric pressure and gauge pressure is called absolute pressure. I need more explaination