The term scuba refers to equipment and techniques that allow divers to explore underwater environments independently of surface breathing gas supplies. In scuba diving, divers use compressed air or a gas blend with increased oxygen content (nitrox) for their main source of breathing during the dive. Scuba diving allows deeper exploration of the oceans than can be accomplished with surface supply only, but it is still a hazardous activity that requires special training and knowledge of diving physics and decompression theory to be safely practised.

Divers typically dive in pairs, for safety & to help each other out should something go wrong during the dive. A good buddy will check your equipment before you dive, ensure you are correctly weighted and will stay close during the whole dive in case of an emergency. Visibility, or viz is the clarity of the water and you will often hear divers refer to it as ‘good viz’ or ‘bad viz’.

In the 19th century, scientific and technologic advances greatly accelerated underwater exploration. Scientists like Paul Bert and John Scott Haldane were able to better understand the effects of water pressure on the human body and define safe limits for compressed air diving. Meanwhile, improvements in scuba equipment allowed divers to stay under the sea for longer periods of time.

A scuba rebreather recycles a diver’s exhaled gases by circulating out carbon dioxide and filtering back in unused oxygen, eliminating the need for surface gas supply. They have become very popular with recreational divers.