Ice skating is the act of motion by wearer of the ice skates to propel the participant across a sheet of ice. This can be done for a variety of reasons, including exercise, leisure, traveling, and various sports. Ice skating occurs both on specially prepared ice surfaces (arenas, tracks, parks), both indoors and outdoors, as well as on naturally occurring bodies of frozen water, such as ponds, lakes and rivers.
Research suggests that the earliest ice skating happened in southern Finland more than 4,000 years ago. This was done to save energy during winter journeys. Originally, skates were merely sharpened, flattened bone strapped to the bottom of the foot. Skaters did not actually skate on the ice, but rather glided on top of it.
A skate can glide over ice because there is a layer of ice molecules at the surface that are not as tightly bound as the molecules of the mass of ice beneath. These molecules are in a semiliquid state, providing lubrication. The molecules in this "quasi-fluid" or "water-like" layer are less mobile than liquid water, but are much more mobile than the molecules deeper in the ice.
Construction of an ice rink requires an experienced designer. An individual with this expertise is rarely found in an architectural firm unless they have previous experience in recreation centers, especially ones that feature aquatic centers and ice rinks. Just as indoor pools have special construction concerns caused by warm, humid environment with atmospheric contamination from chorine to treat the water, ice rinks pose specific problems from cold, damp environments causing mold, plus problems related to carbon monoxide from the resurfacing equipment, and potential accidental leaks of ammonia into the building.
In general, the rink size is 90–110 m (300–360 ft) x 45–65 m (148–213 ft). For internationals, the size must not be smaller than 100 metres (330 ft) x 60 metres (200 ft). The variety rink bandy is played on ice hockey rinks.