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Measurements and Light – Celebrating World Metrology Day

by AprilSix Proof

Wednesday 20th May was World Metrology Day. This is a global celebration to mark the anniversary of the signing of The Metre Convention on 20 May 1875.

140 years later this agreement still provides the basis for a single, coherent system of measurements that are traceable to the International System of Units (SI). This system enables accurate measurement to underpin the welfare of our society, from providing confidence in trade and innovation to ensuring our transport infrastructure and healthcare systems are safe.


The theme for World Metrology Day 2015 is ‘Measurements and Light’, chosen to align with the UNESCO International Year of Light and Light-based technologies 2015 (IYL).  This global initiative highlights the importance of light and optical technologies in addressing worldwide challenges in areas such as energy, education, communications, health, and sustainability.

The National Physical Laboratory (NPL) is the home of measurement in the UK, and light is at the forefront of their work. This includes the lasers used to cool atoms in NPL’s high-accuracy caesium fountain atomic clock, to the new optical method, which provides direct SI traceability for sound pressure.

Proof worked with NPL recently to develop and publish a special edition of its Insights magazine. Published to coincide with World Metrology Day, it examines the role of light in a variety of applications, including energy generation and communications. It also includes contributions from the UK National Committee for IYL and the Bureau International des Poids et Mesures.

World Metrology Day is organised and celebrated jointly by the International Bureau of Weights and Measures and the International Organization of Legal Metrology with the participation of National Measurement Institutes like NPL.

Find out more about World Metrology Day 2015

Download the official World Metrology Day 2015 poster

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