John M. Steele
Sat, 04 Sep 2010 17:26:17 -0700
Per this Wikipedia article http://en.wikipedia.org/wiki/Vienna_Standard_Mean_Ocean_Water the isotopic compostition of water can change the triple point a few hundred microkelvins.
A change of 28 cm elevation (at sea level) changes standard pressure (obviously weather varies pressure too) enough to change the boiling point of water by 1 millikelvin, and is a far worse "standard" than triple point. I don't disagree with the need for a better kelvin, but a boiling point definition would be a giant step backward. ________________________________ From: James R. Frysinger <j...@metricmethods.com> To: U.S. Metric Association <usma@colostate.edu> Sent: Sat, September 4, 2010 7:44:56 PM Subject: [USMA:48465] Re: Universal Teperature Scale (*UT) RE: Re: kelvin The triple point for water is hard to reproduce with precision as well. It is highly dependent on isotope ratios and ionic content. I would imagine that leachates from the glass cell are a problem. This difficulty is one reason that a new definition for the kelvin is being sought. Jim On 2010-09-04 1822, John M. Steele wrote: > The steam point is a TERRIBLE fundamental standard because it is quite > pressure dependent. That pressure dependence is the basis of: > *Steam Tables (and steam engines) > *Pressure cookers > *High altitude instructions in cooking > Even the melting point is slightly pressure dependent. Under the modern > definitions, even at standard pressure the melting and boiling points > are not PRECISELY 0°C and 100 °C. > > ------------------------------------------------------------------------ > *From:* Brij Bhushan Vij <metric...@hotmail.com> > *To:* U.S. Metric Association <usma@colostate.edu> > *Sent:* Sat, September 4, 2010 1:41:31 PM > *Subject:* [USMA:48463] Universal Teperature Scale (*UT) RE: Re: kelvin > > Sirs: > It is not my desire to confuse the 'kelvin Tempertaure Scale (*º*K)' or > the new emerging need for its revision. > However, I pointed a method to resolve */"Negative Temperatures" in > 1982, /*if and when the need to re-consideration of defining KELVIN - > the thermodynamic temperature scale, arose. KELVIN was accepted at 13th > CGPM (1967) as the unit for thermodynamic temperature - as the fraction > 1/273.16 at tripple point of water. > I placed the 'idea of extending' the thermodynamic scale between > *Absolute Zero (-273.16ºC) and Steam Point (100.00**ºC), *thus making > each 100-graduation as 1-degree Universal Temperature Scale i.e. 1-UT > =(273.16+100) div.100 =3.7316*K. This idea had been placed between pages > 87 thro 90 in my book Towards A Unified Technology (1982) among the > Chapter SI UNITS - REDEFINED (pages 72 thro 95). > Brij Bhushan Vij > (MJD 55443)/1726+D-244W36-06 (G. Saturday, 2010 September 04H13:69 > (decimal) EST > Aa Nau Bhadra Kritvo Yantu Vishwatah -Rg Veda > The Astronomical Poem (revised number of days in any month) > "30 days has July,September, > April, June, November and December > all the rest have 31 except February which has 29 > except on years divisible evenly by 4; > except when YEAR divisible by 128 and 3200 - > as long as you remember that > "October (meaning 8) is the 10th month; and > December (meaning 10) is the 12th BUT has 30 days & ONE > OUTSIDE of calendar-format" > Jan:31; Feb:29; Mar:31; Apr:30; May:31; Jun:30 > Jul:30; Aug:31; Sep:30; Oct:31; Nov:30; Dec:30 > (365th day of Year is World Day) > ******As per Kali V-GRhymeCalendaar***** > "Koi bhi cheshtha vayarth nahin hoti, purshaarth karne mein hai" > My Profile - http://www.brijvij.com/bbv_2col-vipBrief.pdf > Author had NO interaction with The World Calendar Association > except via Media & Organisations to who I contributed for A > Possible World Calendar, since 1971. > HOME PAGE: http://www.brijvij.com/ > Contact via E-mail: metric...@hotmail.com > > > > ------------------------------------------------------------------------ > Date: Sat, 4 Sep 2010 04:39:37 -0700 > From: jmsteele9...@sbcglobal.net > Subject: [USMA:48462] Re: kelvin > To: usma@colostate.edu > > I was also a bit confused on this, as well as thermodynamic temperature > vs the ITS-90 practical temperature scale. The first link is from our > friend Anthony O'Conner. I am aware many people have set him to > "ignore," but the article is worth a read. The second is a follow-on > link from the first on ITS-90. The two, taken together, clarified things > a bit for me. > http://www.nature.com/news/2009/170609/full/459902a.html > http://www.nature.com/news/2009/170609/full/459902a/box/1.html > > ------------------------------------------------------------------------ > *From:* "mech...@illinois.edu" <mech...@illinois.edu> > *To:* U.S. Metric Association <usma@colostate.edu> > *Sent:* Fri, September 3, 2010 12:04:56 AM > *Subject:* [USMA:48460] Re: kelvin > > > The triple point of water is the temperature at which the solid, liquid, > and gas phases of isotopically natural water are in equilibrium. This > temperature is the single fixed point of the "kelvin thermodynamic > temperature scale"; defined numerically to be 273.16 kelvins. > > How can Boltzmann's constant be used to improve this scale? > Where can we read the proposal for the 2011 CGPM meeting? > > ---- Original message ---- > >Date: Thu, 2 Sep 2010 20:41:10 +0100 > >From: "Martin Vlietstra" <vliets...@btinternet.com > <mailto:vliets...@btinternet.com>> > >Subject: RE: [USMA:48457] Re: kelvin > >To: <mech...@illinois.edu <mailto:mech...@illinois.edu>>, "'U.S. > Metric Association'" <usma@colostate.edu <mailto:usma@colostate.edu>> > > > >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. > -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108