What weighs a kilogram
In a luxurious building in the suburbs of Paris, in a sealed box with a vacuum seal, under three glass domes, hidden small metal cylinder the size of a palm, known around the world as the international prototype Kilogram, or «Le Grand K«. Created in 1879 from an alloy of platinum and iridiumcylinder was called the «perfect» kilogram — the gold standard by which scientists evaluate all other kilograms. Despite…