Difference between revisions of "New SI"

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"'''New SI'''" or "'''quantum SI'''" are terms used to refer to a series of proposed changes in the [[International System of Units]] (SI), which will lead to the redefinition of the [[kilogram]] and up to three other [[base unit]]s in terms of fundamental [[physical constant]]s. The changes will not take effect until the 24th meeting of the [[General Conference on Weights and Measures]] (CGPM) in autumn 2011 at the earliest.
 
"'''New SI'''" or "'''quantum SI'''" are terms used to refer to a series of proposed changes in the [[International System of Units]] (SI), which will lead to the redefinition of the [[kilogram]] and up to three other [[base unit]]s in terms of fundamental [[physical constant]]s. The changes will not take effect until the 24th meeting of the [[General Conference on Weights and Measures]] (CGPM) in autumn 2011 at the earliest.
  
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The main object of "new SI" is to find an alternative for the [[International Prototype Kilogram]] as a [[mass]] standard. The kilogram is the only one of the SI base units still to be defined in terms of a [[prototype standard]], and intercomparison of national prototypes suggests that the stability of these standards is not as great as had previously been assumed. The favoured option is to redefine the kilogram in terms of a defined value of the [[Planck constant]]. At the same time, the redefinition of the [[mole (unit)|mole]], the [[ampere]] and the [[kelvin]] (in terms of the [[Avogadro constant]], the [[elementary charge]] and the [[Bolzmann constant]] respectively) is also under consideration.
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The main object of "new SI" is to find an alternative for the [[International Prototype Kilogram]] as a [[mass]] standard. The kilogram is the only one of the SI base units still to be defined in terms of a [[prototype standard]], and intercomparison of national prototypes suggests that the stability of these standards is not as great as had previously been assumed. The favoured option is to redefine the kilogram in terms of a defined value of the [[Planck constant]], although other proposals have also been made. At the same time, the redefinition of the [[mole (unit)|mole]], the [[ampere]] and the [[kelvin]] (in terms of the [[Avogadro constant]], the [[elementary charge]] and the [[Bolzmann constant]] respectively) is also under consideration.<ref name="1-CI-2005">[http://www.bipm.org/cc/CIPM/Allowed/94/CIPM-Recom1CI-2005-EN.pdf Recommendation 1 (CI-2005)], 94th&nbsp;meeting of the [[International Committee for Weights and Measures]] (CIPM), 2005.</ref>
  
 
==Kilogram==
 
==Kilogram==
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<ref>[http://www.bipm.org/en/CGPM/db/20/5/ Resolution 5], 20th&nbsp;meeting of the [[General Conference on Weights and Measures]] (CGPM), 1995.</ref><ref>[http://www.bipm.org/en/CGPM/db/21/7/ Resolution 7], 21st&nbsp;meeting of the [[General Conference on Weights and Measures]] (CGPM), 1999.</ref><ref>Recommendation G1, [http://www.bipm.org/utils/common/pdf/CCM9.pdf 9th&nbsp;meeting of the Consultative Committee for Mass and Related Quantities (CCM)], 2005.</ref><ref name="U1-2005">Recommendation U1, [http://www.bipm.org/utils/common/pdf/CCU17.pdf 17th&nbsp;meeting of the Consultative Committee for Units (CCU)], 2005.</ref><ref name="1-CI-2005">[http://www.bipm.org/cc/CIPM/Allowed/94/CIPM-Recom1CI-2005-EN.pdf Recommendation 1 (CI-2005)], 94th&nbsp;meeting of the [[International Committee for Weights and Measures]] (CIPM), 2005.</ref><ref>[http://www.bipm.org/wg/CCM/CCM-WGSI-kg/Allowed/General/CCM_document_to_CCU-CIPM_May07.pdf Report of the CCM to the CIPM], May 2007.</ref><ref>[http://www.bipm.org/en/CGPM/db/23/12/ Resolution 12], 23rd&nbsp;meeting of the [[General Conference on Weights and Measures]], 2007.</ref>
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<ref>[http://www.bipm.org/en/CGPM/db/20/5/ Resolution 5], 20th&nbsp;meeting of the [[General Conference on Weights and Measures]] (CGPM), 1995.</ref><ref>[http://www.bipm.org/en/CGPM/db/21/7/ Resolution 7], 21st&nbsp;meeting of the [[General Conference on Weights and Measures]] (CGPM), 1999.</ref><ref>Recommendation G1, [http://www.bipm.org/utils/common/pdf/CCM9.pdf 9th&nbsp;meeting of the Consultative Committee for Mass and Related Quantities (CCM)], 2005.</ref><ref name="U1-2005">Recommendation U1, [http://www.bipm.org/utils/common/pdf/CCU17.pdf 17th&nbsp;meeting of the Consultative Committee for Units (CCU)], 2005.</ref><ref name="1-CI-2005"/><ref>[http://www.bipm.org/wg/CCM/CCM-WGSI-kg/Allowed/General/CCM_document_to_CCU-CIPM_May07.pdf Report of the CCM to the CIPM], May 2007.</ref><ref>[http://www.bipm.org/en/CGPM/db/23/12/ Resolution 12], 23rd&nbsp;meeting of the [[General Conference on Weights and Measures]], 2007.</ref>
  
 
<ref>{{citation | first1 = W. | last1 = Schwitz | first2 = B. | last2 = Jeckelmann | first3 = P. | last3 = Richard | title = Towards a new kilogram definition based on a fundamental constant | journal = C. R. Phys. | volume = 5 | issue = 8 | pages = 881–92 | year = 2004}}.</ref>
 
<ref>{{citation | first1 = W. | last1 = Schwitz | first2 = B. | last2 = Jeckelmann | first3 = P. | last3 = Richard | title = Towards a new kilogram definition based on a fundamental constant | journal = C. R. Phys. | volume = 5 | issue = 8 | pages = 881–92 | year = 2004}}.</ref>
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<ref>{{citation | last1 = Andres | first1 = Hanspeter | last2 = Haerri | first2 = Hans-Peter | last3 = Niederhauser | first3 = Bernhard | last4 = Wunderli | first4 = Samuel | last5 = Feller | first5 = Ulrich | title = No Rationale for a Redefinition of the Mole  | journal = Chimia Int. J. Chem. | volume = 63 | issue = 10 | year = 2009 | pages = 616–18 | doi = 10.2533/chimia.2009.616}}.</ref>
 
<ref>{{citation | last1 = Andres | first1 = Hanspeter | last2 = Haerri | first2 = Hans-Peter | last3 = Niederhauser | first3 = Bernhard | last4 = Wunderli | first4 = Samuel | last5 = Feller | first5 = Ulrich | title = No Rationale for a Redefinition of the Mole  | journal = Chimia Int. J. Chem. | volume = 63 | issue = 10 | year = 2009 | pages = 616–18 | doi = 10.2533/chimia.2009.616}}.</ref>
 
<ref>{{citation | last = Leonard | first = B. P. | year = 2010 | title = Comments on recent proposals for redefining the mole and kilogram | journal = Metrologia | volume = 47 | issue = 3 | pages = L5–L8 | doi = 10.1088/0026-1394/47/3/L01}}.</ref>
 
<ref>{{citation | last = Leonard | first = B. P. | year = 2010 | title = Comments on recent proposals for redefining the mole and kilogram | journal = Metrologia | volume = 47 | issue = 3 | pages = L5–L8 | doi = 10.1088/0026-1394/47/3/L01}}.</ref>
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==Ampere==
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<ref>Recommendation E1, [http://www.bipm.org/utils/common/pdf/CCEM25.pdf 25th&nbsp;meeting of the Consultative Committee on Electricity and Magnetism], 2007.</ref>
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==Kelvin==
  
 
==Notes and references==
 
==Notes and references==

Revision as of 07:13, 27 August 2010

"New SI" or "quantum SI" are terms used to refer to a series of proposed changes in the International System of Units (SI), which will lead to the redefinition of the kilogram and up to three other base units in terms of fundamental physical constants. The changes will not take effect until the 24th meeting of the General Conference on Weights and Measures (CGPM) in autumn 2011 at the earliest.

The main object of "new SI" is to find an alternative for the International Prototype Kilogram as a mass standard. The kilogram is the only one of the SI base units still to be defined in terms of a prototype standard, and intercomparison of national prototypes suggests that the stability of these standards is not as great as had previously been assumed. The favoured option is to redefine the kilogram in terms of a defined value of the Planck constant, although other proposals have also been made. At the same time, the redefinition of the mole, the ampere and the kelvin (in terms of the Avogadro constant, the elementary charge and the Bolzmann constant respectively) is also under consideration.[1]

Kilogram

[2][3][4][5][1][6][7]

[8] [9] [10] [11] [12] [13]

Mole

[14] [15] [16] [17]

Ampere

[18]

Kelvin

Notes and references

Notes

References

  1. ↑ 1.0 1.1 Recommendation 1 (CI-2005), 94th meeting of the International Committee for Weights and Measures (CIPM), 2005.
  2. ↑ Resolution 5, 20th meeting of the General Conference on Weights and Measures (CGPM), 1995.
  3. ↑ Resolution 7, 21st meeting of the General Conference on Weights and Measures (CGPM), 1999.
  4. ↑ Recommendation G1, 9th meeting of the Consultative Committee for Mass and Related Quantities (CCM), 2005.
  5. ↑ Recommendation U1, 17th meeting of the Consultative Committee for Units (CCU), 2005.
  6. ↑ Report of the CCM to the CIPM, May 2007.
  7. ↑ Resolution 12, 23rd meeting of the General Conference on Weights and Measures, 2007.
  8. ↑ Schwitz, W.; Jeckelmann, B.; Richard, P. Towards a new kilogram definition based on a fundamental constant. C. R. Phys. 2004, 5 (8), 881–92.
  9. ↑ Robinson, I. Redefining the kilogram. Phys. World 2004, 17 (5), 31–35.
  10. ↑ Mills, I. M.; Mohr, P. J.; Quinn, T. J.; Taylor, B. N.; Williams, E. R. Redefinition of the kilogram, ampere, kelvin and mole: a proposed approach to implementing CIPM recommendation 1 (CI-2005). Metrologia 2006, 43 (3), 227–46. DOI: 10.1088/0026-1394/43/3/006.
  11. ↑ Leonard, B. P. Note on invariant redefinitions of SI base units for both mass and amount of substance. Metrologia 2006, 43 (1), L3–L5. DOI: 10.1088/0026-1394/43/1/L01.
  12. ↑ Becker, P.; De Bièvre, P.; Fujii, K.; Glaeser, M.; Inglis, B.; Luebbig, H.; Mana, G. Considerations on future redefinitions of the kilogram, the mole and of other units. Metrologia 2007, 44 (1), 1–14. DOI: 10.1088/0026-1394/44/1/001.
  13. ↑ Petley, B. W. The atomic units, the kilogram and the other proposed changes to the SI. Metrologia 2007, 44 (1), 69–72. DOI: 10.1088/0026-1394/44/1/010.
  14. ↑ Recommendation U1, 15th meeting of the Consultative Committee for Amount of Substance: metrology in chemistry (CCQM), 2009.
  15. ↑ Mills, Ian; Milton, Martin Amount of Substance and the Mole. Chem. Int. 2009, 31 (2), 3–7, <http://www.iupac.org/publications/ci/2009/3102/1_mills.html>.
  16. ↑ Andres, Hanspeter; Haerri, Hans-Peter; Niederhauser, Bernhard; Wunderli, Samuel; Feller, Ulrich No Rationale for a Redefinition of the Mole. Chimia Int. J. Chem. 2009, 63 (10), 616–18. DOI: 10.2533/chimia.2009.616.
  17. ↑ Leonard, B. P. Comments on recent proposals for redefining the mole and kilogram. Metrologia 2010, 47 (3), L5–L8. DOI: 10.1088/0026-1394/47/3/L01.
  18. ↑ Recommendation E1, 25th meeting of the Consultative Committee on Electricity and Magnetism, 2007.
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