A kilo is a kilo is a kilo, right? Wrong. Monday marks World Metrology Day, and this year’s edition sees a big change in the way the kilogram unit is defined. In November last year, scientists and ...

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 ...

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 ...

Every measurement we make, be it for length, time, temperature, or electric current, needs a standard unit so that results ...

Breakthroughs, discoveries, and DIY tips sent every weekday. Terms of Service and Privacy Policy. This week, Sam Kean takes a look at some ridiculously precise ...

We measure stuff all the time—how long, how heavy, how hot, and so on—because we need to for things such as trade, health and knowledge. But making sure our measurements compare apples with apples has ...

We’ve long known that there were some issues with France’s ‘Le Grand K’, the international prototype for what a kilogram really is. Made in 1879 from platinum and iridium alloy, it is the perfect ...

The time has finally come for the metric system’s long-scheduled upgrade. Next week, the General Conference on Weights and Measures (CGPM) will meet for the 26th time. When it does, it will revamp the ...

THROUGHOUT MUCH of human history, man has been the measure of many, if not all, things. Lengths were divided up into feet, palms, spans and smaller units derived from the human hand. Other measures ...

It has been used as a standard unit of weight measurement since the time of the French revolution, based on the precise mass of a lump of metal held in Paris. But the kilogram may be about to be given ...

Scientific units are set to receive their biggest shake-up since the inception of the modern metric system in 1960. The International Bureau of Weights and Measures (BIPM) -- one of three committees ...