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 ...

How do you define one kilogram? Easy: it's the exact mass of a metal cylinder called the International Prototype Kilogram, IPK for short, kept in controlled conditions in France. But the standard ...

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 ...

“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 ...

France holds the world’s standard for the kilogram weight. It’s a cylinder-shaped object that has dictated all other kilogram weights for 130 years now. As it’s made from platinum-iridium though, the ...

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” ...