Until 2018, the SI unit of mass, the kilogram, was defined as the mass of a real object: the International Prototype Kilogram, kept in a secure facility in the outskirts of Paris. On November 16, 2018 ...

Since 1889, Le Grand K, a sleek cylinder of platinum-iridium metal, has ruled from its underground vault in Paris. An absolute monarch, it was the very definition of 1 kilogram of mass. Scientists ...

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 measuring Planck's constant with the NIST Kibble balance, researchers carefully measured the effects of the magnetic field that is generated to counteract the weight of masses. In their experiments ...

The watt balance—also known as the Kibble balance—is a precision electromechanical instrument that has revolutionised the realisation of the kilogram by linking it directly to the Planck constant.

Hackers, advanced hobbyists, makers, and hands-on physics experimenters are always looking for their next great project, and I think this is a good one: an apparatus to establish the “standard” ...