How is absolute pressure defined?

Absolute pressure is defined as the total pressure exerted on an object, which includes both the atmospheric pressure and any additional pressure that results from being submerged underwater. When a diver descends, the pressure increases due to the weight of the water column above them, adding to the surface atmospheric pressure. This means that absolute pressure accounts for the entirety of the pressure experienced at a given depth, providing a complete picture of the environmental conditions a diver faces.

By understanding absolute pressure, divers can better gauge the effects of pressure on their bodies, including how this impacts buoyancy, gases in the body, and the danger of decompression sickness. Absolute pressure is crucial for safe diving practices as it helps divers calculate factors related to the dive environment, such as their air consumption and the significance of equalizing pressure in their ears and sinuses.