An upcoming change to SI units – due to be officially approved this month – will mark the end of a long journey from defining quantities in terms of objects to using precise, unchanging and universal ...

“The mother ship is never wrong,” said Robert Vocke Jr, a chemist at the National Institute of Standards and Technology in Gaithersburg, Maryland. No longer. Friday, in a small conference centre just ...

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 ...

It doesn’t happen too often, but after a vote that took place earlier today near Paris, science textbooks really will have to be rewritten. At the Congress Chamber in the Palace of Versailles, ...

In addition to Ampere, Kelvin, Mol and Co., the kilogram also is now defined by a natural constant. In concrete terms, this means that the original kilogram, which has been the measure of all things ...

Mass is a property of matter which is not dependent on the temperature of the object in space. The SI unit of mass is kilogram (kg). The prototypes of the International standard kilogram is available ...

The official definition of a kilogram has been changing for well over a century, but this week it may be redefined for the final time. After years of debate and discussion, scientists from around the ...

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 ...

In addition to Ampere, Kelvin, Mol and others, the kilogram is now defined by a natural constant. In concrete terms, this means that the original kilogram, which has been the measure of all things for ...

In addition to other scientific units, the kilogram also is now defined by a natural constant. This is made possible by single crystals grown from highly enriched silicon-28. In addition to Ampere, ...