World Metrology Day 2018
The World Metrology Day (WMD) is an annual celebration of the signature of the Metre Convention, the international treaty that paved the way for the creation and adoption of the International System of measurement units (SI). The Convention was signed on May 20, 1875 by representatives of seventeen nations. For a long time, commerce, industry and science had been asking for a common language to express their meaurements: the SI was the answer.
Every year select a topical and relevant theme for the WMD.
Over the time, the International System has been changing many times: we need only think of the SI at its beginning: the base units were only three, while, nowadays, these have become seven. After kilogramme. metre, and second, measuring mass, length, and time, kelvin, ampere, candela, and mole were added for temperature, electric current, amount of substance, and luminous intensity, respectively. All further units (such as hertz, newton, pascal, watt...) are then obtained as products of powers of the seven base units, so they are called derived units.
The next approaching change will be the redefinition of the measurement units in terms of fundamental physical constants.
For several years, the metrological community has been working to prepare for this change. It will be a major breakthrough since it will enable more accurate and stable reference standards for the maesurement units. Also, it will be possible to realise such reference standards everywhere.
The 26th meeting of the General Conference on Weights and Measures, to be held on November 13-16, 2018, in Versailles, will ratify this redefinition that will then come into force in 2019.
In view of this next revolution, the theme of the WMD 2018 could not have been nothing but the International System and its constant evolution from 1875 until today.
The World Metrology Day project is realized by the Bureau International des Poids et Mesures (BIPM) and the International Organization of Legal Metrology (OIML).
The poster for 2018 was designed by the Federal Institute of Metrology METAS, the Swiss Metrology Institute. The slogan "constant evolution" was proposed by INRIM.