Recent advances on the redefinition of the kilogram |
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| Richard Davis |
- Abstract:
- The International System of Units (SI) still relies on an artifact standard to define the unit of mass, the kilogram. The unit of electrical current, the ampere, is defined in terms of a force in newtons, which in turn is traceable to the kilogram. It has long been appreciated that the mass of any artifact, such as the international prototype of the kilogram, will certainly vary with respect to a so-called "fundamental" constant of mass, such as the mass of an atom of carbon-12. Until recently, however, there was no highly accurate experimental method that might link the mass of a macroscopic artifact to the mass of a fundamental constant. However, this situation is changing rapidly. Simultaneously with these developments, electrical metrology is now firmly based on fundamental constants, but these constants have rather large uncertainties due to the need to link the ampere to the kilogram in the present SI. Finally, in the field of fundamental constants, the need to measure certain of the constants in terms of the artifact kilogram in order to arrive at their SI values is becoming increasingly cumbersome. The present situation, as outlined above, has led to proposals to redefine a number of the SI base units.
- Download:
- IMEKO-TC3-2007-PL-085u.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC3
- Event name:
- Cultivating Metrological Knowledge
- Title:
20th Conference on Measurement of Force, Mass and Torque (together with 3rd TC16 Conference on Pressure Measurement & 1st TC22 Conference on Vibration Measurement)
- Place:
- Merida, MEXICO
- Time:
- 27 November 2007 - 01 December 2007