Diving mask in the context of "Underwater diving"

Pearl hunting, also known as pearl fishing or pearling, is the activity of recovering or attempting to recover pearls from wild molluscs, usually oysters or mussels, in the sea or freshwater. Pearl hunting was prevalent in India and Japan for thousands of years. On the northern and north-western coast of Western Australia pearl diving began in the 1850s, and started in the Torres Strait Islands in the 1860s, where the term also covers diving for nacre or mother of pearl found in what were known as pearl shells.

In most cases the pearl-bearing molluscs live at depths where they are not manually accessible from the surface, and diving or the use of some form of tool is needed to reach them. Historically the molluscs were retrieved by freediving, a technique where the diver descends to the bottom, collects what they can, and surfaces on a single breath. The diving mask improved the ability of the diver to see while underwater. When the surface-supplied diving helmet became available for underwater work, it was also applied to the task of pearl hunting, and the associated activity of collecting pearl shell as a raw material for the manufacture of buttons, inlays and other decorative work. The surface supplied diving helmet greatly extended the time the diver could stay at depth, and introduced the previously unfamiliar hazards of barotrauma of ascent and decompression sickness.

Snorkeling (snorkelling in British and Commonwealth English) is the practice of swimming face-down in a body of water while breathing the ambient air through a shaped tube called a snorkel, usually with swimming goggles or a diving mask, and swimfins. In cooler waters, a wetsuit is also worn. The use of this equipment allows the snorkeler (British and Commonwealth English spelling: snorkeller) to observe the underwater environment for extended periods with relatively little effort, and to breathe while face-down at the surface.

Snorkeling is a popular recreational activity, particularly at tropical resort locations. It provides the opportunity to observe underwater life

Tempered or toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tension. Such stresses cause the glass, when broken, to shatter into small granular chunks instead of splintering into large jagged shards as ordinary annealed glass does. These smaller, granular chunks are less likely to cause deep penetration when forced into the surface of an object (e.g. by gravity, by wind, by falling onto them, etc.) compared to larger, jagged shards because the reduction in both the mass and the maximum dimension of a glass fragment corresponds with a reduction in both the momentum and the penetration depth of the glass fragment.

Tempered glass is used for its safety and strength in a variety of applications, including passenger vehicle windows (apart from windshield), shower doors, aquariums, architectural glass doors and tables, refrigerator trays, mobile phone screen protectors, bulletproof glass components, diving masks, and plates and cookware.

Underwater football is a two-team underwater sport that shares common elements with underwater hockey and underwater rugby. As with both of those games, it is played in a swimming pool with snorkeling equipment (mask, snorkel, and fins).

The goal of the game is to manoeuvre (by carrying and passing) a slightly negatively buoyant ball from one side of a pool to the other by players who are completely submerged underwater. Scoring is achieved by placing the ball (under control) in the gutter on the side of the pool. Variations include using a toy rubber torpedo as the ball, and weighing down buckets to rest on the bottom and serve as goals.

A full-face diving mask is a type of diving mask that seals the whole of the diver's face from the water and contains a mouthpiece, demand valve or constant flow gas supply that provides the diver with breathing gas. The full face mask has several functions: it lets the diver see clearly underwater, it provides the diver's face with some protection from cold and polluted water and from stings, such as from jellyfish or coral. It increases breathing security and provides a space for equipment that lets the diver communicate with the surface support team.

Full-face masks can be more secure than breathing from an independent mouthpiece; if the diver becomes unconscious or suffers an oxygen toxicity convulsion, the diver can continue to breathe from the mask, unlike a scuba mouthpiece which is normally gripped between the teeth.