Final answer:
Gauge pressure is the pressure on a liquid that does not include atmospheric pressure. Absolute pressure, on the other hand, is the total pressure which is the sum of gauge pressure and atmospheric pressure.
Step-by-step explanation:
The pressure on a liquid that does not include atmospheric pressure is known as gauge pressure. Unlike gauge pressure, absolute pressure accounts for atmospheric pressure, which in effect adds to the pressure in any fluid not enclosed in a rigid container. It is important to understand that atmospheric pressure contributes to the pressure in an open system because of Pascal's principle. Therefore, the total pressure, or absolute pressure, is the sum of gauge pressure and atmospheric pressure, expressed in the equation: Pabs = Pg + Patm, where Pabs is absolute pressure, Pg is gauge pressure, and Patm is atmospheric pressure.