A popular adventure activity, scuba involves diving underwater using a self-contained breathing apparatus and a supply of compressed gas at a controlled pressure. This allows scuba divers to explore the ocean’s depths and discover its marine life and geological formations.

Divers must be in good health and must undergo a medical exam before they can dive. This is because diving can expose divers to nitrogen narcosis or decompression sickness, which are often caused by rapid changes in pressure when moving up and down through the water column.

The 1-3 Rule is an important safety rule that requires divers to descend no more than one meter per second and ascend no faster than three meters per second. This helps prevent decompression illness, as well as allowing the diver time to adjust to changing pressure.

The early scuba equipment was quite restrictive, however, the invention of a mask and fins made it easier for people with poor swimming skills to enjoy the underwater world. The modern BCD (Buoyancy Control Device, or BC) is worn on the diver’s back and contains an inflatable system that keeps them positively buoyant on the surface and neutrally buoyant when diving. The BCD also makes it easy to add or release air as needed.

Divers are trained to deal with a range of underwater emergencies, the most urgent of which is running out of breathing gas. This is called an out-of-air emergency and can be managed in several ways, including relying on a buddy for oxygen or carrying an independent alternative breathing source.