Pressure is defined as force per unit area. Static pressure is the pressure in or due to a non-moving fluid, such as water. A fluid does not sustain shearing forces, thus a force that compresses the object is the only force transferrable by a liquid. This fact leads to the conclusion that an object submerged in a fluid will feel only a force perpendicular to each surface.

Two kinds of pressure are commonly discussed: absolute pressure and atmospheric pressure. Atmospheric pressure is an arbitrary value based on the atmosphere of the planet, in our case, Earth. We feel a pressure exerted by the atmosphere no matter where we are or what we are doing. The average value on Earth is 1.0 x 105 Pascals or 760 mm of Hg (14.7 psi) at sea level, but it changes with altitude and weather conditions. Even though everything on...