[CODATA-international] A milestone in the history of science based on work of the CODATA, the Committee on Data of the International Science Council

Asha CODATA asha at codata.org
Thu Nov 15 10:50:17 EST 2018

*[image: CC BY-ND 4.0 BIPM]The General Conference of Weights and Measures
will meet in Paris to vote on whether to re-define the International System
of Units (SI) for the kilogram, ampere, kelvin and mole based on
fundamental laws rather than measurement.*

A unique event in the history of science is scheduled for Friday 16th
November when a meeting in Versailles, France, will vote whether to
re-define the International System of Units (SI) based on exact values of
the fundamental constants. This would mean, for example, that the
International Prototype of the Kilogram – a lump of metal which has been
used to determine measurement of the kilogram since 1889 – will be replaced
by a precise value deduced from fundamental laws of science.

[image: CC BY-ND 4.0 BIPM]The values are the work of the CODATA Task Group
on Fundamental Physical Constants, which, every few years since 1969, has
summarised and evaluated the cumulative work of scientists and
technologists in publishing a recommended set of self-consistent values of
the fundamental constants of nature. Their most recent work[1] has been to
determine the exact values of the Planck constant h, the elementary charge
e, the Boltzmann constant k, and the Avogadro constants NA, so that the
value of four of the SI base units — the kilogram, ampere, kelvin, and mole
(measures of mass, electric current, temperature, and amount of substance,
respectively) — are no longer fixed by measurement, but are deduced from
fundamental laws. They will join the other three base units — the second,
metre, and candela (a measure of a light’s perceived brightness) — that are
already defined in this way. The change will make the units more stable and
allow investigators to develop ever more precise and flexible techniques
for converting the constants into measurement units.

The decision will be made by the General Conference of the International
Bureau of Weights and Measures,  an inter-governmental organization,
established in 1875, as the supreme authority through which member states
(60 member states + 42 associate states) act together to agree the values
of the fundamental constants. Does this matter? Yes, it matters profoundly.
Since the earliest human civilisations, precise measurement has been a
staple of honest trade and exchange, and as science and technologies have
advanced, has been vital to science’s understanding of the universe, to the
precision and utility of technological devices, to the terms and
trustworthiness of trade and commerce, and to the everyday lives of

Geoffrey Boulton, retiring President of CODATA and member of the ISC
Governing Board, commented that

“it is important that we scientists recognize the magnitude and potential
significance of this achievement, as one of CODATA’s proudest moments in
its 50-year history, and to applaud not only the members of its current
Task Group
under its co-chairs David Newell and Barry Wood, but all their predecessors
since 1969. In recognition of their achievements, the General Assembly of
CODATA, held last week, agreed, by unanimous acclamation, to award the 2018
biennial CODATA Prize to the Task Group.”

The prize rewards outstanding achievement in advancing data for science. It
is the first time that the prize has been awarded to a group rather than an

*Images are CC BY-ND 4.0 BIPM*

For more, please visit:


[1] “The CODATA 2017 values of h, e, k, and NA for the revision of the SI
<http://iopscience.iop.org/article/10.1088/1681-7575/aa950a/pdf>,” Newell
et al., Metrologia 55 L13-16 (2017)


Asha Law | Program Assistant, CODATA | http://www.codata.org

E-Mail: asha at codata.org
Tel (Office): +33 1 45 25 04 96

CODATA (Committee on Data of the International Council for Science), 5 rue
Auguste Vacquerie, 75016 Paris, FRANCE
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