Scuba diving is a sport that lets people explore the underwater world, including oceans, lakes, rivers and caves. Most people learn to dive for recreational reasons, to experience the beauty of the ocean or lakes below the surface, but some commercial divers and scientists use scuba to investigate the marine environment.

Equipment

Divers wear a mask, fins and a tank on their back to breathe air. They also have depth and pressure gauges to help them navigate while they are under water.

The most important piece of diving equipment is the scuba tank, which stores compressed air that the diver can breathe. The pressure of the air is the same as ambient air at sea level, but the diver can stay underwater for a longer time with this air supply.

A bailout cylinder is an emergency breathing gas supply that a scuba diver can rely on in the event that they run out of their main scuba tank. There are several different systems to provide this backup breathing gas, but the most common system is a secondary second stage that uses the primary first stage to share the gas supply.

Diving Safety

Scuba diving is a very dangerous sport, and it is advisable to only dive under professional supervision. A qualified dive master will monitor the diving conditions and notify the diver if something looks amiss. The most common hand signal for this is the “Everything’s Okay” sign, with the thumb and index finger making a circle.