Gene: I thought the correct terminology was "kelvins" in the plural. Can you tell me if that's correct?
Ezra Gene Mechtly wrote: > Allow me to correct my own error before others notice it. > > The zero on the "Celsius" scale is 273.15 kelvin, not 273.16 kelvin. > (NIST SP 811, page 5) > > These temperatures are, however, correctly stated as the "ice point" and > the "tripple point" respectively, and the "tripple point" is more > accurately realized in laboratories, as stated below. > > The subtle difference between the centigrade and Celsius scales is not so > simply explained as I attempted to do below. What is the difference? > > Gene. > ....................................... > > On Sat, 2 Mar 2002, Gene Mechtly wrote: > > > On Thu, 28 Feb 2002, Stephen Davis asked: > > > > > ... why Centigrade was replaced by Celsius!! > > > > Steve, > > > > The kelvin scale of temperature is *defined* by fixing a *single* > > reference temperature, the "triple point" temperature of pure water, > > at exactly 273.16 kelvin. (where "triple point" means the temperature > > of ice, water, and water vapor in equilibrium) > > > > > > The zero on the Celsius scale is fixed at the "triple point" of water; > > at 273.16 kelvin. > > > > On the other hand, the zero on the centigrade scale had been set at > > the "ice point" of water, at 273.15 kelvin. (the temperature of melting > > ice) > > > > Although the difference is only 0.01 kelvin, the "triple point" is more > > accurately realized in laboratories than the "ice point", and therefore > > the Celsius scale is preferable to the centigrade scale. > > > > See Resolution 3 of the 9th CGPM of 1948, Page 122 in the BIPM Booklet. > > > > Gene. > >
