Why is air that is pressurized needed in scuba diving?

Answer 1

The pressure on a diver's body increases quickly with depth. At the surface we're all breathing air at 14.7 PSIg, or 1 "Atmosphere" (atm). Each 33 feet of sea water results in another 1 atm of pressure. This means, for example, that a diver's body is under a total pressure of 3 atmospheres at 66 feet of sea water (one of air, two of water).

The human respiratory system is designed to operate at normal atmospheric pressure of 14.7 pounds per square inch. If we descend to 33 feet, the water pressure exerts a force of nearly 30 pounds per square inch on our bodies. Our bodies are incapable of breathing against that much pressure. A Scuba pressure regulator is designed to deliver air at the same pressure as the surrounding water, allowing us to breathe.

Answer 2

A person can only breath air that has the same pressure has his or her surroundings. Under water, the pressure will go up fairly quickly (every 10 meter / 33 feet of water exert the same pressure as that on the surface) and the scuba gear will make sure the diver gets air with the same pressure as that of the surroundings.

Answer 3

A scuba diver needs pressure in an air tank because water pressure increases and pushes down on their lungs as they go down. The air in your lungs is more compressed and more is needed to fill them completely.

Answer 4

Air pressure creates a 'base amount' of pressure to the scuba divers. There is the effect that it adds on a small amount of pressure as well as the water pressure.