Celsius Celsius The Celsius scale, also known as the centigrade scale, is a temperature scale used by the International System of Units (SI). As an SI derived unit, it is used by all countries except the United States, the Bahamas, Belize, the Cayman Islands and Liberia. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was
Celsius same is "40°C ± 3 K", which can be commonly found in literature. Celsius measurement follows an interval system but not a ratio system; and it follows a relative scale not an absolute scale. For example, 20 °C is not twice the heat energy of 10 °C; and 0 °C is not the lowest Celsius value. Thus, degrees Celsius is a useful interval measurement but does not possess the characteristics of ratio measures like weight or distance. In science and in engineering, the Celsius scale and the Kelvin scale are often used in combination in close contexts, e.g. "a measured