Underwater Diving and Scuba Diving

Scuba diving is a type of underwater diving. In this form of diving, the diver carries his/her own compressed air apparatus to breathe when he/she is under water. This allows them to stay under water for a longer period of time.

Originally, SCUBA was used as an acronym for self contained under water breathing apparatus. Typically, a scuba set consists of air hose, mouth piece, regulator, harness, back plate, and the tank. People perform scuba diving for personal as well as professional reasons. People dive for recreational purposes and there a many different disciplines like cave diving, wreck diving, ice diving, and deep diving.

Professional scuba divers are employed by companies to perform certain underwater tasks. These tasks include oil exploration, underwater welding, repair and inspection of boats and ships, salvage of wrecks, spear fishing, etc. It is not enough if air is simply supplied to a scuba diver. As the diver goes down, water also exerts pressure on the chest and lungs apart from the normal atmospheric pressure. It is approximately 1 bar for every 33 feet of depth. As such, the pressure of the inhaled air should match with the ambient pressure so that the lungs remain inflated. The regulator, that is part of a scuba set, ensures that air is supplied at ambient pressure. This enables the diver to inhale and exhale naturally and effortlessly at any depth.

Visibility is a problem for people under water as the refractive index of water is higher than that of air, but same as that of the cornea of the eye. The diving masks and helmets are designed to resolve this problem. They create an air space in front of the diver's eyes. The error in refraction created by water is corrected when light travels from water to air through a flat lens. However, the objects appear about 34% bigger and nearly 25% closer than they actually are. As the field of view gets reduced, adjustment of eye-hand coordination is essential. Generally, divers who use corrective glasses will need to use the same glasses when wearing the mask.

How safe is scuba diving? It is a sport with risks like any other. It is the fear associated with drowning and the nervousness of using the scuba set that makes it seem riskier. Scuba diving is not as dangerous as some other activities that we take up without hesitation. The truth is that the number of fatalities is coming down every year, despite the fact that the number of divers has increased by leaps and bounds.