October 18, 2010 marked the 50th anniversary of the International System of Units, also known as the SI System. Resolution 12 of the 11th meeting of the CGPM (1960) established the system as the world ...

Taking the first steps of what would be a major historical advance in the science of measurement, the U.S. National Institute of Standards and Technology is participating in a worldwide effort to ...

The International System of Units (SI Units), adopted in 1960, is the global standard for consistent measurement, replacing disparate systems. It has 7 base si units and all other units are derived ...

Weighty matters: a platinum-iridium kilogram belonging to the US National Institute of standards and Technology. (Courtesy: J.L. Lee/NIST) Metrologists and policy-makers from 60 countries around the ...

For the first time in more than 30 years, new terms have been officially added to the International System of Units (SI). The four new prefixes – ronna, quetta, ronto and quecto – describe very large ...

Deluged by responses to his request for your favourite units, Robert P Crease discovers that non-SI units persist, and are sometimes even popular, among the physics community Setting the standard ...

The US refusal to use SI radiation units is confusing and dangerous. It’s time to make the switch. There are two types of nation: those that use the metric system and those that have put a man on the ...

If scientists had sacred objects, this would be one of them: a single, closely guarded 137-year-old cylinder of metal, housed in a vault outside of Paris. It is a prototype that precisely defines a ...