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 ...

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 ...

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 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 ...

A new definition of the kilogram is required, an international team of scientists contends. The current one is imprecise, they say, because it is not linked to an unvarying property of nature. The ...

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, ...