Move the locator and see temperature measurements on the Celsius, Fahrenheit, Kelvin and Rankine scales. Since 1954, Celsius has been defined by the triple point of Vienna Standard Mean Ocean Water (VSMOW), which identifies 0.01 Celsius with 273.16 Kelvin and makes a change of 1° Celsius equivalent to a change of 1° Kelvin. This means that the melting point of VSMOW water is 0° Celsius but its boiling is not taken to define 100° anymore. Instead, the boiling point of water is approximately 99.9839° Celsius.
Celsius is defined by "Vienna Standard Mean Ocean Water." Wikipedia. (April 18, 2007) http://en.wikipedia.org/wiki/VSMOW.
Wolfram Demonstrations Project
Published: March 7 2011