The kilogram may need to go on a diet. The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms in weight from surface ...

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 ...

From being used in science experiments to weighing everyday objects, the kilogram has been a useful unit of measurement that has remained unchanged for more than a century now. That run could be ...

Using a state-of-the-art Theta-probe XPS machine, experts in the UK have shown the original kilogram is likely to be tens of micrograms heavier than it was when the first standard was set in 1875. And ...