For more than a century, a single metal cylinder in a Paris vault quietly defined what a kilogram was. After 130 years, ...

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 ...

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 a landmark decision, representatives from 60 countries voted to redefine the International System of Units (SI), changing the world's definition of the kilogram, the ampere, the kelvin and the mole ...

Talk about massive change. After meeting the needs of science, industry and commerce for more than 130 years, the kilogram has just been fundamentally reinvented. At a meeting Friday in Versailles, ...

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 ...

Brynn Hibbert receives funding from ARC, International Union of Pure and Applied Chemistry (IUPAC). He is Past President of the Royal Society of New South Wales, Past Chair of the Analytical Division ...

The scientists who define the world's weights and measures pride themselves on their fastidiousness — so a proposal this week to smooth diverging measurements of the kilogram, the SI unit of mass, is ...

After decades of worry, toil and argument, metrologists have officially begun the process of tying the definitions of four basic units to nature’s fundamental constants. The General Conference on ...

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, ...