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BIPM e-learning courses on fundamental metrology

The BIPM Physical Metrology Department has developed two CBKT e-learning courses on the kilogram - the fundamental unit of mass in the International System of Units (SI), which was redefined on 20 May 2019. The courses describe how to realize the mass unit and how the kilogram is disseminated following its redefinition.

Two e-learning courses are available:

  • Dissemination of the kilogram following its redefinition. This course describes the different phases of the dissemination of the kilogram, from internationally coordinated dissemination, based on the so-called consensus value, to independent dissemination from local realization experiments. The determination of the consensus value and its consequences on mass dissemination from National Metrology Institutes is also covered.
  • Realization of the kilogram following its redefinition.  This course discusses why the definition was changed and the benefits of the new definition. It explains the two methods approved by the Consultative Committee for Mass and Related Quantities (CCM) for the realization of the kilogram: the Kibble balance and the X-ray crystal density (XRCD) method. The course also explains the benefits of the new definition for the metrology of masses much smaller than 1 kg.  The course consists of three parts:
    1. The new definition of the kilogram
    2. The operation of the Kibble balance
    3. The X-ray crystal density method

The courses are available at: and require self-enrolment. Interested participants can use their e-learning credentials (or create an account) to take part in the courses.