Convert K to °C

Kelvin

Definition: The Kelvin (symbol: K) is the base unit of temperature in the International System of Units (SI), used alongside the Celsius scale. The Kelvin scale is an absolute, thermodynamic temperature scale where absolute zero, the coldest possible temperature, is 0 K. The scale's unit increments are equal to those of the Celsius scale.

History/origin: The Kelvin scale is named after the British physicist William Thomson, 1st Baron Kelvin. He proposed the concept of absolute temperature in 1848. In 1954, the 10th General Conference on Weights and Measures defined the Kelvin scale in terms of the triple point of water (273.16 K). In 2019, the General Conference on Weights and Measures redefined the Kelvin in terms of the Boltzmann constant, but the scale maintains its previous values.

Current use: The Kelvin scale is primarily used in scientific contexts. It is used in fields like physics, engineering, and chemistry. It is the standard unit of temperature in scientific measurement.

Celsius

Definition: The Celsius scale (symbol: °C) is a temperature scale used by the International System of Units (SI). As defined today, zero degrees Celsius is equal to 273.15 K, with a temperature difference of 1 deg C equivalent to a difference of 1 K, meaning the scale is now defined by two fixed points: absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW), a specially purified water.

History/origin: The Celsius scale was proposed by the Swedish astronomer Anders Celsius in 1742. In Celsius's original scale, zero represented the boiling point of water and 100 represented the freezing point. This was reversed after his death in 1744 to create the current scale, where zero represents the freezing point of water and 100 represents the boiling point, at standard atmospheric pressure.

The scale was known as the centigrade scale until 1948 when the 9th General Conference on Weights and Measures renamed it to honor Anders Celsius. The term "centigrade" refers to the 100-degree interval between the defined points.

In 1954, the 10th General Conference on Weights and Measures defined the Celsius scale in terms of the triple point of water (0.01 °C) and absolute zero (-273.15 °C), making it directly derivable from the Kelvin scale. In 2019, the definition was updated to be based on the Boltzmann constant, maintaining the same temperature values but with a more fundamental definition.

Current use: The Celsius scale is used worldwide for most temperature measurements, including weather forecasts, body temperature, and in scientific contexts. It's part of the metric system and is used in nearly all countries.