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 ...

Metrology, the branch of science dedicated to measurement, has created better and better systems of measurement for the kilogram based on fundamental principles rather than arbitrary chunks of metal ...

Planck’s constant is equal to 6.626069934 x 10−34 kg∙m2/s, they said. And their uncertainty was just 13 parts per billion. That number may be barely intelligible to the casual observer. But to Pratt, ...

SINGAPORE — A kilogram is hard to fathom. It is a unit of mass, but humans can only sense force and not mass, hence the frequent confusion between mass and weight, which is a type of force, said Mr ...

As cheat sheets go, it is a long one. Every four years, a task force of the Committee on Data for Science and Technology (CODATA), headquartered in Paris, releases a short-hand description of the ...

Humanity is on the verge of a weighty achievement. On Friday, representatives of more than 60 nations will convene in Versailles, France, to approve a new definition for the kilogram. Since the 19th ...