[USMA:48458] Re: kelvin

[Martin Vlietstra]

There is of course talk of a proposal to redefine the temperature scale at
the 2011 meeting of the CGPM by defining the value of Boltzmann's constant
and using that definition to derive the triple point of water etc.  

-----Original Message-----
From: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf
Of mech...@illinois.edu
Sent: 02 September 2010 19:35
To: U.S. Metric Association
Subject: [USMA:48457] Re: kelvin


Correction:

The quotation below on calibration contained only the letters "CCT", not the
full name of the CCT which is the "Consultative Committee on Thermometry"
(not "on Temperature" which I had incorrectly identified.)

-- Original message ----
>Date: Wed,  1 Sep 2010 17:34:14 -0500 (CDT)
>From: <mech...@illinois.edu>  
>Subject: [USMA:48456] Re: kelvin  
>To: "U.S. Metric Association" <usma@colostate.edu>
>
>
>My source of information on questions of temperature is NIST Technical Note
1265; Guidelines for Realizing the International Temperature Scale of 1990
(ITS-90), by B.W. Mangum and G. T. Furukawa, August 1990.
>
>The fixed points of the ITS-90 are Freezing Points, Melting Points, Boiling
Points, or Triple Points of various substances; atoms or molecules. More
than twenty seven are included.
>
>With respect to calibration: "The ITS-90 was designed by the Consultative
Committee on Temperature (CCT) in such a manner that temperature values
obtained on it do not deviate from the kelvin thermodynamic temperature
values by more than the uncertainties of the latter values at the time the
ITS-90 was adopted."  "The size of the kelvin is defined to be 1/273.16 of
the thermodynamic temperature of the triple point of water."
>
>t/(deg C) = T/K - 273.15;  defines thermodynamic temperatures in Celsius.
>
>t(subscript 90) denotes ITS-90 temperatures also in Celsius.
>
>The "International Practical Temperature Scale" IPTS-of 1968 (amended in
1975). has been formally abrogated.
>
>t and t(subscript 90) are not the same.