Possible Implications of the Principle of the ‘Mise en Pratique’ in its Application to the Kelvin (original) (raw)
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2014
The terms of reference for Working Group 1 of the Consultative Committee for Thermometry1 (CCT WG1), as established at the 23rd meeting of the CCT, state in part [1]: Working Group 1 is tasked... to coordinate a task group (including a representative from Working Groups 3, 4, and 5) formulating an assessment and possible work plan for the next International Temperature Scale and to prepare and maintain the mise en pratique for the definition of the kelvin. In response to this charge, the Mise-en-Pratique Task Group has produced the present document. We begin in Section 2 by reviewing the status of the mise en pratique for the definition of the kelvin (MePK), including a discussion of possible extensions of the MePK. Over the next few years, we anticipate adding sections on supplementary information for the Provisional Low Temperature Scale of 2000 (PLTS-2000), low-temperature gas thermometry, absolute radiation thermometry, and the known differences between thermodynamic temperature...
Metrologia, 2006
The International System of Units (SI) is founded on seven base units, the metre, kilogram, second, ampere, kelvin, mole and candela corresponding to the seven base quantities of length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity. At its 94th meeting in October 2005, the International Committee for Weights and Measures (CIPM) adopted a recommendation on preparative steps towards redefining the kilogram, ampere, kelvin and mole so that these units are linked to exactly known values of fundamental constants. We propose here that these four base units should be given new definitions linking them to exactly defined values of the Planck constant h, elementary charge e, Boltzmann constant k and Avogadro constant N A , respectively. This would mean that six of the seven base units of the SI would be defined in terms of true invariants of nature. In addition, not only would these four fundamental constants have exactly defined values but also the uncertainties of many of the other fundamental constants of physics would be either eliminated or appreciably reduced. In this paper we present the background and discuss the merits of these proposed changes, and we also present possible wordings for the four new definitions. We also suggest a novel way to define the entire SI explicitly using such definitions without making any distinction between base units and derived units. We list a number of key points that should be addressed when the new definitions are adopted by the General Conference on Weights and Measures (CGPM), possibly by the 24th CGPM in 2011, and we discuss the implications of these changes for other aspects of metrology.
2014
The International System of Units (SI) is founded on seven base units, the metre, kilogram, second, ampere, kelvin, mole and candela corresponding to the seven base quantities of length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity. At its 94th meeting in October 2005, the International Committee for Weights and Measures (CIPM) adopted a recommendation on preparative steps towards redefining the kilogram, ampere, kelvin and mole so that these units are linked to exactly known values of fundamental constants. We propose here that these four base units should be given new definitions linking them to exactly defined values of the Planck constant h, elementary charge e, Boltzmann constant k and Avogadro constant NA, respectively. This would mean that six of the seven base units of the SI would be defined in terms of true invariants of nature. In addition, not only would these four fundamental constants have exactly defined values bu...
The Roles of the Mise en Pratique for the Definition of the Kelvin
International Journal of Thermophysics, 2010
The mise en pratique ("practical realization") for the definition of the kelvin (MeP-K) was created by the Consultative Committee for Thermometry (CCT) in 2006 to give practitioners of thermometry a guide to the realization of the kelvin, i.e., measurement of temperature in kelvins, in accord with the International System of Units. In this article, the present and the future content of the MeP-K, the relationship of the MeP-K to other documents relevant to thermometry, the categorization of thermometry techniques in the MeP-K, and the benefits of proposed additions to the 2006 version of the MeP-K are discussed. The three categories of measurements within the MeP-K are: (1) primary methods for measuring thermodynamic temperature T ;
Metrologia, 1996
Recommended values of temperature on the International Temperature Scale of 1990 are given for a large number of secondary reference points, together with assessments of the uncertainties of these values. * The exceptions are the freezing point of antimony, where is taken to be -0,125 K (the defined value), rather than the value from the equation (-0,1257 K); the freezing point of mercury; and the triple points of gallium and indium. The latter three points are so very near the corresponding ITS-90 defining fixed points that their temperatures on the ITS-90 can be found more accurately directly from temperature differences. ** The only exceptions are the freezing point of mercury and the triple points of gallium and indium. The differences in temperature of these three points from those of the corresponding ITS-90 defining fixed points, respectively, are known to better than 1 mK (as shown) and so the temperatures are listed to the 0,1 mK level.
2008
The historical case study of Daniel Gabriel Fahrenheit’s creation of the first mercury thermometer with reliable scales is used as the basis for a lesson that is designed to provide students with a richer insight into the arbitrary nature of thermometer scales. The lesson attempts to move students beyond a level of understanding that is based simply on knowing how to read and use a thermometer, to a level of understanding that is based on knowing the very procedures and principles used to create thermometric scales. By studying the criteria that Fahrenheit used to create his scale, students should begin to obtain a richer insight into the arbitrary nature of thermometer scales in general. It is argued that it is insufficient to teach students how to read and use thermometers without giving them some notion of how a scale came into existence because no real insight is being provided into the nature of science. Students must be introduced to the actual procedures used by scientists if...
Report to the CIPM on the implications of changing the definition of the
2000
The International Committee for Weights and Measures (CIPM) approved, in its Recommendation 1 of 2005, preparative steps towards new definitions of the kilogram, the ampere, the kelvin and the mole in terms of fundamental constants. Within the Consultative Committee for Thermometry (CCT), a task group (TG-SI) has been formed to consider the implications of changing the definitions of the above-mentioned base units of the SI, with particular emphasis on the kelvin and the impact of the changes on metrology in thermometry. The TG-SI has presented the results of its deliberations to the CCT and to the Consultative Committee for Units, CCU, and worked with them to prepare this report to the CIPM.
2015
ABSTRACT: The historical case study of Daniel Gabriel Fahrenheit’s creation of the first mercury thermometer with reliable scales is used as the basis for a lesson that is designed to provide students with a richer insight into the arbitrary nature of thermometer scales. The lesson attempts to move students beyond a level of understanding that is based simply on knowing how to read and use a thermometer, to a level of understanding that is based on knowing the very procedures and principles used to create thermometric scales. By studying the criteria that Fahrenheit used to create his scale, students should begin to obtain a richer insight into the arbitrary nature of thermometer scales in general. It is argued that it is insufficient to teach students how to read and use thermometers without giving them some notion of how a scale came into existence because no real insight is being provided into the nature of science. Students must be introduced to the actual procedures used by sci...