Scuba (Self-Contained Underwater Breathing Apparatus) is an apparatus utilizing a portable supply of compressed gas supplied at a regulated pressured and used for breathing while swimming underwater.
The apparatus is often called “scuba gear”, a “scuba system” or simply “scuba”.
Scuba is also the common name for the sport (also called “diving” or “scuba diving”) which is uses the apparatus for recreational diving.
There are two kinds of scuba equipment:
- The Aqua-lung is a tank (or cyclider) of compressed gas (usually air or mixture similar to air) which is supplied to a diver through a regulator, which adjust the pressure of the gas to suit the ambient pressure for comfortable breathing. This kind of scuba system is called “open circuit” because the exhaled gas is released into the water and lost. The open circuit aqua-lung is the most common type of scuba system used by recreational divers.
- The Rebreather is also a tank (or cyclider) of compressed gas breathed by the diver through a regulator, but with other mechanisms that recycle the exhaled gas. This kind of scuba system is called “closed circuit” The economy of reusing and recycling exhaled gases allows a diver to remain submerged for longer periods.