Scuba, or self-contained underwater breathing apparatus, is a recreational diving experience that allows divers to explore the wonders of the ocean depths while remaining fully immersed in the water. It is a form of underwater exploration used by recreational and professional divers around the world to view ship wrecks, natural coral reefs and marine animals up close. Scuba can also be used in rescue, search and recovery missions and underwater welding jobs.

Diving involves a lot of gear – there is the scuba tank, mask, snorkel and all of the other specialized equipment needed to stay safe. The first step to any dive is to suit up – this is usually done at the dive site and includes getting in the water, walking through the surf to the dive site and then exiting the same way you entered. It takes some practice to be able to do this without making a mess of your dive equipment.

Definitions:

Absorption & Elimination – the gases (usually nitrogen) that are absorbed into the tissues during the dive and need to be eliminated on ascent to prevent decompression sickness. Nitrogen is eliminated from the body through the tissue’s lungs, and is released in an exponential fashion based on depth. This theory is referred to as the Haldane model and is the basis for dive tables and algorithms for dive computers.

Buoyancy Control – the ability to maintain a constant depth while maintaining neutral buoyancy. This is achieved by using an air/gas mixture and adjusting it as required by the dive profile. Gas mixtures include standard oxygen and nitrox, but also helium which is used for very deep diving as it does not cause narcosis to the same degree.