Scuba diving .

Divers who engage in scuba diving employ breathing apparatus that is entirely independent of a surface air source. Christian J. Lambertsen came up with the moniker "scuba," which stands for "Self-Contained Underwater Breathing Apparatus," in a 1952 patent application. Scuba divers can move more freely and independently than surface-supplied divers and spend longer underwater than free divers since they have their own source of breathing gas, typically compressed air. Despite the widespread usage of compressed air, enriched air, sometimes known as nitrox, has gained popularity due to the decreased nitrogen consumption during lengthy and/or frequent dives. Additionally, helium-diluted breathing gas can be utilised to lessen the risk and consequences of nitrogen narcosis during.