The Kelvin scale is a scale that measures temperatures beginning with absolute zero, the lowest possible temperature at which matter can exist. According to the Kelvin scale, absolute zero is 0° Kelvin, fresh water freezes at 273.15° Kelvin, and fresh water boils at 373.15° Kelvin. The Kelvin temperature scale is named after William Thomson Kelvin (1824-1907), the British physicist (a scientist specializing in the interaction between matter and energy) who devised it in 1848.
Temperature is the level of heat in a gas, liquid, or solid. The freezing and boiling points of water are used as standard reference levels in both the metric scales (centigrade or Celsius) and the English scale (Fahrenheit).
In the metric scale, the difference between freezing and boiling is divided into 100 equal intervals called degrees Celsius or degrees centigrade (° C). In the English scale, this difference is divided into 180 units, with 1 unit called a degree Fahrenheit (° F). A degree Kelvin (symbol K) has the same value as a degree Celsius, but the two temperatures differ by 273.15 degrees (for instance, absolute zero is 0 Kelvin on the Kelvin scale and 273.15° Celsius on the Celsius scale).
Below is a comparison of the three temperatures:
|Freezing point of water||273.15||0||32|
|Normal human body temperature||310.15||37||98.6|
|Boiling point of water||373.15||100||212|
To convert Celsius to Kelvin: Add 273.15 to the temperature (K = C + 273.15). To convert Fahrenheit to Celsius: Subtract 32 from the temperature and multiply the difference by 5, then divide the product by 9 (C = [F - 32] X 5 - 9). To convert Celsius to Fahrenheit: Multiply the temperature by 1.8, then add 32 (F = [1.8XC] + 32).
Sources: Emiliani, Cesare. The Scientific Companion, pp. 34-35; Giscard d'Estaing, Valerie-Anne. The World Almanac Book of Inventors, p. 246; The Universal Almanac 1992, p. 530.