This Kilogram Has A Weight-Loss Problem

This Kilogram Has A Weight-Loss Problem:

More than a century ago, a small metal cylinder was forged in London and sent to a leafy suburb of Paris. The cylinder was about the size of a salt shaker and made of an alloy of platinum and iridium, an advanced material at the time.

Since 1889, the year the Eiffel Tower opened, that cylinder has been the standard against which every other kilogram on the planet has been judged. But that's creating problems. According to scientists, the cylinder's mass appears to be changing.

(Thanks, inky)

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Article:

• http://givemesomethingtoread.com/post/168152064