US Objects To the Kilogram

Velcroman1 writes "For 130 years, the kilogram has weighed precisely one kilogram. Hasn't it? The US government isn't so sure. The precise weight of the kilogram is based on a platinum-iridium cylinder manufactured 130 years ago; it's kept in a vault in France at the International Bureau of Weights and Measures. Forty of the units were manufactured at the time, to standardize the measure of weight. But due to material degradation and the effects of quantum physics, the weight of those blocks has changed over time. That's right, the kilogram no longer weighs 1 kilogram, according to the National Institute of Standards and Technology. And it's time to move to a different standard anyway. A proposed revision would remove the final connection to that physical bit of matter, said Ambler Thompson, a NIST scientist involved in the international effort. 'We get rid of the last artifact.'"

Comments

Re:Get rid of the artifact?

[MartinSchou]

But all you need to know is, they're using it to determine the mass of one mole of silicon atoms.

From there on, they'll theoretically be able to deduce a perfect kilogram and it won't have anything to do with lumps of metal ever again.

Yes ... apart from the fact that silicon IS a metal, and that a large collection of atoms that closely together is rightfully called a "lump".

Essentially they're proposing replacing one lump of metal with another. It may not be a cylinder, but it's still a lump of metal.