Wetsuit

A close-fitting garment, usually made of neoprene, that reduces heat loss in water by trapping a thin layer of water between the suit and the skin.

Neoprene: A synthetic rubber containing gas-filled cells, used for its flexibility and thermal insulation. Its closed-cell structure traps gas and gives most wetsuits their insulating layer.
Closed-cell foam: Foam made of discrete gas-filled cells that resist water absorption. Closed cells in neoprene retain insulating gas even when the suit is immersed.
Scuba diving: Underwater diving in which a diver carries a supply of breathing gas. Divers use wetsuits to reduce heat loss during prolonged immersion.
Drysuit: A waterproof suit that keeps the wearer dry by sealing out water. Unlike a wetsuit, it relies on a waterproof barrier and insulating underlayers.
Thermal conductivity: A material property describing how readily heat flows through it. A wetsuit slows heat transfer between the body and surrounding water.
Specific heat capacity: The heat required to raise the temperature of a unit mass of a substance by one degree. Water's high heat capacity makes immersion a rapid source of body heat loss.
Surfing: A water sport in which a person rides a board on a moving wave. Surfers wear wetsuits to stay warm during repeated exposure to cold water and wind.
Rash guard: A close-fitting shirt, usually made from stretchy fabric, that protects skin from abrasion and sun. It offers skin protection but little thermal insulation compared with neoprene.
Convection: Heat transfer through the bulk movement of a fluid such as water or air. A snug fit limits the flushing of warmed water that would carry body heat away.
Evaporative cooling: Cooling caused when a liquid absorbs heat as it evaporates. A wetsuit reduces exposed wet skin, limiting evaporation after leaving the water.

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