Boilingwater

Boiling water is the heating of water to its boiling point, the temperature at which liquid water rapidly converts to steam. At standard atmospheric pressure, pure water boils at 100 degrees Celsius, and the process is marked by the formation of vapor bubbles within the liquid that rise to the surface. Boiling differs from simmering, which occurs below the boiling point, and from evaporation, which happens at all temperatures but slowly.

Boiling point depends on pressure. Higher pressure raises the boiling point, enabling liquids to reach temperatures above 100°C in devices like pressure cookers; lower pressure lowers the boiling point, so water boils at temperatures well below 100°C on high mountains. Dissolved substances raise boiling point slightly in a phenomenon known as boiling point elevation; thus salty water boils at a somewhat higher temperature than pure water.

Applications include cooking foods, sterilizing water for safety, and preparing beverages. For disinfection, water is typically boiled long enough to inactivate pathogens; times vary with altitude. Boiling is also used in industrial processes and in rapid purification methods when other filtration options are unavailable.

In practice, achieving a boil involves heating in a competent vessel until vigorous bubbling occurs, often followed by maintaining a rolling boil if cooking requires agitation or heat transfer. Cautions include steam burns and mineral buildup in kettles from hard water, which can reduce efficiency over time.