Celsiusskalaen

Celsiusskalaen, or the Celsius scale, is a widely used temperature scale named after the Swedish astronomer Anders Celsius. In 1742 he proposed a centigrade scale for measuring temperature. He initially defined the scale with 0 degrees at the boiling point of water and 100 degrees at the freezing point, but after his death the scale was inverted to its current convention: 0 degrees lowest, 100 degrees highest for water under standard atmospheric pressure.

In the modern Celsius scale, 0 °C is defined as the freezing point of water at one atmosphere (standard pressure, 1013.25 hPa), and 100 °C as the boiling point at the same pressure. The degree Celsius is the unit used to express temperature in this scale, and the Celsius scale is closely connected to the Kelvin scale used in science. The relation between them is simple: K = °C + 273.15, so 0 °C equals 273.15 K.

Usage and scope: Celsius is the standard temperature scale for most of the world in weather reporting, cooking, education, and daily life. In scientific contexts, temperature measurements often use Kelvin, but Celsius remains common for practical purposes and public communications. The United States frequently uses Fahrenheit in everyday settings, though Celsius is used in science, medicine, and many international standards.

See also: Kelvin, Fahrenheit, temperature, thermodynamics.