Absolute temperature, also called thermodynamic temperature, is the temperature of an object on a scale where 0 is taken as absolute zero. Absolute temperature scales are Kelvin (degree units Celsius) and Rankine (degree units Fahrenheit).
Absolute zero is the temperature at which a system is in the state of lowest possible (minimum) energy. As molecules approach this temperature their movements drop towards zero. It is the lowest temperature a gas thermometer can measure. No electronic devices work at this temperature.
Common temperatures in the absolute scale are:
- 0 °C (freezing point of water) = 273.15 K
- 25 °C (room temperature) = 298.15 K
- 100 °C (boiling point of water) = 373.15 K
- 0K (absolute zero) = - 273.15 Celsius
To convert from the Celsius scale into the absolute temperature, you add 273.15 and change °C to K. To get a temperature on the absolute scale to the Celsius scale, subtract 273.15 and change K to °C. This is normally used in the science world. Kelvin is used globally as a part of the International System of Units. It is one of the 7 base units of the system. The value if Absolute temperature is 0K.
- Celsius to Kelvin: K=C+273.15
- Kelvin to Celsius: C=K-273.15
- Fahrenheit to Rankine: R=F+460
- Rankine to Fahrenheit: F=R-460