Snorkeling

Snorkeling is surface swimming with the face submerged while breathing through a snorkel. It allows observation of underwater environments without scuba equipment.

Snorkel: A breathing tube that lets a swimmer breathe while keeping the face underwater. Its open end stays above water while the swimmer looks below the surface.
Snorkel breathing: Breathing through a tube whose opening remains above the water surface. The snorkel supplies air only while its opening remains out of the water.
Coral reef: A marine ecosystem built largely by colonies of reef-forming corals. Clear, shallow reefs are common snorkeling sites, but contact can damage fragile organisms.
Scuba diving: Underwater diving using self-contained breathing equipment. Scuba equipment supplies breathing gas underwater; snorkeling uses a tube only at the surface.
Diving mask: A sealed face covering that creates an air space in front of the eyes underwater. It keeps water from the eyes and nose and provides a clear view underwater.
Dead space (respiration): Air in the respiratory passages that does not participate directly in gas exchange. A snorkel adds exhaled air that can be rebreathed, especially when its volume is large.
Marine protected area: A defined marine region managed to conserve habitats, species, or cultural resources. Rules in protected areas can limit where snorkelers swim and how they interact with wildlife.
Surface-supplied diving: Diving in which breathing gas is delivered from the surface through a hose. It enables sustained underwater breathing, unlike snorkeling's surface-limited air supply.
Swim fins: Footwear with broad blades that increase propulsion through water. They help snorkelers move efficiently with relaxed leg kicks.
Hydrostatic pressure: Pressure exerted by a fluid at rest, which increases with depth. Even slight submersion makes breathing through a surface-level tube harder against water pressure.

Linked from 7 pages