TEMPERATURE SCALE

The temperature scale adopted by a 1960 international conference was based on a fixed temperature point, the Triple Point of water, at which the solid, liquid, and gas are in equilibrium. The temperature of 273.16 K (Kelvin) was assigned to this point. The freezing point of water was designated as 273.15 K, equaling exactly 0 on the Celsius Temperature Scale. The Celsius scale, which is identical to the Centigrade Temperature Scale, is named for the 18th-century Swedish astronomer Anders Celsius, who first proposed the use of a scale in which the interval between the freezing and boiling points of water is divided into 100 degrees. By international agreement, the term Celsius has officially replaced Centigrade.