Fluid Mechanics B. Pressure Key Concepts Pressure is the force acting perpendicular to a given surface area. Pressure is a scalar quantity, acting in all directions. Meteorologists express pressure in millibars.
Atmospheric pressure decreases at higher elevations.
Standard atmospheric pressure will support a column of mercury 760 mm high. This can be expressed as a pressure of 760 mm Hg, or 760 Torr. A barometer is used to measure atmospheric pressure. The pressure is independent of the total volume or the shape of the container. Demonstrate an understanding of accepted usage of units for pressure.