Scientists set to vote on weighty issue ”“ the redefinition of the  kilogram

Leaders of the international measurement community from more than 60 countries will come together tomorrow in France for an historic vote on changes to the metric system, which will lead to a landmark redefinition of the  kilogram.

The proposed redefinition of the International System of Units (SI) ”“ more commonly known as the metric system ”“ will take place on 16 November at the 26th  General Conference on Weights and Measures in Versailles, France, organised by the International Bureau of Weights and Measures (BIPM).

If the resolution is endorsed it will mean that, from 20 May 2019, all SI units will be defined in terms of fundamental constants of nature.

This will help guarantee the long-term stability and reliability of international measurement standards to support advances in science and technology.

The most significant change will be the end of the  International Prototype of the  Kilogram  (or “Big K”), a cylinder of platinum-iridium stored in a vault at the BIPM in France.

Big K  has served science and technology well for nearly 130 years. However, over time, there have been small changes to the artefact.

Redefining the  kilogram  removes the reliance on a physical object that could be unstable.

The President of the International Committee for Weights and Measures (CIPM) and inaugural CEO of the National Measurement Institute (NMI) Australia, Dr Barry Inglis, will preside over the meeting.

It will also be his last meeting as CIPM President, the most prestigious position in international measurement science, and one which he has occupied as the first Australian and only the second non-European.

“We find ourselves at a landmark moment in our journey,” Dr Inglis said.

“After years of research, it’s now possible to justify a major revision of the SI. This decision, if taken, will represent a significant scientific achievement.

“This will be a tribute to the commitment of resources within the national metrology institutes throughout the world and BIPM, the scientific expertise and dedication within these institutes, and the great spirit of international cooperation, without which such an accomplishment would not have been possible.”

Metrology is the science of measurement and NMI is the peak Australian body responsible for biological, chemical, legal, physical and trade measurement.

NMI is responsible for providing Australia’s interface with the international measurement system, including alignment with the revised SI.

It is working hard to ensure there will be no disruption to industry. For most, it will appear that not much has changed.

However, the revised SI will be an essential support to facilitate technological innovation. Just as the redefinition of the “second” in 1967 provided the basis for technology that has transformed how we communicate across the globe, through GPS and the internet, the new changes will have wide-reaching impact in science, technology, trade, health and the environment, among many other sectors.

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