Pressure In Water
Pressure Increases in Salt Water
0 ft
33 ft
66 ft
99 ft
Absolute Pressure in Salt Water
A 33-foot square inch column of salt water weights exactly 14.7 pounds, and exerts 1 atmosphere of pressure. Therefore, absolute pressure increases by 1 atmosphere every 33 feet.
As the graph to the left illustrates, the pressure at 0 feet is 1 atmosphere. Because 33 feet of salt water exerts 1 atmosphere, the absolute pressure at 33 feet is 2 atmospheres. Pressure continues to increase by 1 atmosphere every 33 feet.
A common mistake divers make when calculating absolute pressure is forgetting the 1 atmosphere of pressure at the surface. Remember, absolute pressure is the combination of pressure from both water AND air.
As the graph to the left illustrates, the pressure at 0 feet is 1 atmosphere. Because 33 feet of salt water exerts 1 atmosphere, the absolute pressure at 33 feet is 2 atmospheres. Pressure continues to increase by 1 atmosphere every 33 feet.
A common mistake divers make when calculating absolute pressure is forgetting the 1 atmosphere of pressure at the surface. Remember, absolute pressure is the combination of pressure from both water AND air.
