Deep underneath the Parisian suburb of Saint-Cloud, in a vault that can only be opened by three people wielding three different keys, there lies a hunk of metal that is so crucial to the world of ...

It’s a problem that has been weighing on scientists’ minds for years – how to redefine and accurately measure the kilogram. Currently the unit of measurement is based on a metal cylinder - which ...

Measuring systems are almost always arbitrary – even the orderly metric system is chopped up into random little pieces we call grams, kilograms, and tons. With the increased need for precision, it’s ...

The kilogram may finally get a break from its yo-yo diet. An international team of scientists is closer to redefining the unit of mass based on fundamental constants, instead of a piece of metal in ...

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 ...

Most people know how much a pound weighs — 16 ounces. The worldly among us may know that a kilogram is 2.2 pounds — or 1,000 grams. But do we really know what these numbers mean? Agreeing on units of ...

If John Pratt were an international criminal mastermind, he would fly to Paris, don an all-black suit and ski mask and sneak into the elegant French baroque building that serves as headquarters for ...

In a subterranean vault in a suburb of Paris lies a small, rarely seen metal cylinder known as Le Grand K. For 130 years, this golf-ball-sized hunk of 90% platinum and 10% iridium has served as the ...

Update, May 20th, 2019, 10AM ET: This article was originally published in November 2018. As of May 20th, 2019, World Metrology Day, the new definition of the kilogram based on Planck’s constant has ...