Which noble gas is used in scuba diving?
Argon
Helium
Xenon
Krypton
Helium gas is used in scuba diving as a breathing gas because it reduces the risk of decompression sickness, also known as "the bends." When diving at depths greater than 30 meters (100 feet), divers breathe a mixture of gases to reduce the risk of decompression sickness. This mixture is called "trimix" and typically consists of helium, nitrogen, and oxygen. Helium is used in trimix because it has a low density and is less soluble in the bloodstream than nitrogen, which makes it less likely to cause decompression sickness.
Helium is also used in rebreathers, which are specialized diving equipment that recycles exhaled gases and allows divers to stay underwater for longer periods of time. In rebreathers, the exhaled gas is passed through a scrubber to remove carbon dioxide, and then the remaining gas is enriched with oxygen and helium before being re-breathed by the diver.
Overall, helium is a valuable gas in scuba diving due to its ability to reduce the risk of decompression sickness and extend dive times using rebreathers.