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posted by Fnord666 on Tuesday November 07 2017, @01:27AM   Printer-friendly
from the a-pound-of-feathers-or.... dept.

The kilogram doesn't weigh a kilogram any more. This sad news was announced during a seminar at CERN on Thursday, 26 October by Professor Klaus von Klitzing, who was awarded the 1985 Nobel Prize in Physics for the discovery of the quantised Hall effect. "We are about to witness a revolutionary change in the way the kilogram is defined," he declared.

Together with six other units – metre, second, ampere, kelvin, mole, and candela – the kilogram, a unit of mass, is part of the International System of Units (SI) that is used as a basis to express every measurable object or phenomenon in nature in numbers. This unit's current definition is based on a small platinum and iridium cylinder, known as "le grand K", whose mass is exactly one kilogram. The cylinder was crafted in 1889 and, since then, has been kept safe under three glass bell jars in a high-security vault on the outskirts of Paris. There is one problem: the current standard kilogram is losing weight. About 50 micrograms, at the latest check. Enough to be different from its once-identical copies stored in laboratories around the world.

To solve this weight(y) problem, scientists have been looking for a new definition of the kilogram.

Dang. That throws the easily memorable conversion of 1kg=2.2lbs right out the window.


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  • (Score: 4, Informative) by Pino P on Tuesday November 07 2017, @03:02AM

    by Pino P (4721) on Tuesday November 07 2017, @03:02AM (#593429) Journal

    That throws the easily memorable conversion of 1kg=2.2lbs right out the window.

    I don't see how. The avoirdupois pound is defined in terms of the kilogram:

    So even if the kilogram is redefined in terms of h, the relationship between the pound and the kilogram won't change. This means 1 French-prototype kg = 2.2046 French-prototype lb before the change, and 1 Planck kg = 2.2046 Planck lb after the change.

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