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Kilogram Reference Losing Weight

Posted by CowboyNeal on from the incredible-shrinking-alloys dept.

doubleacr writes "Ran across a story on CNN that says the "118-year-old cylinder that is the international prototype for the metric mass, kept tightly under lock and key outside Paris, is mysteriously losing weight — if ever so slightly. Physicist Richard Davis of the International Bureau of Weights and Measures in Sevres, southwest of Paris, says the reference kilo appears to have lost 50 micrograms compared with the average of dozens of copies.""

3 of 546 comments (clear)

  1. Re:The Kilogram is not losing weight by hjf · · Score: 4, Insightful

    I thought that originally the kilogram was defined in terms of water, the mass of 10 square cm of water.
    I think you meant 1 cubic decimeter.
  2. Re:Mass? by djmurdoch · · Score: 3, Insightful

    I doubt there's any equipment sensitive enough to detect weight difference in an object that was moved several feet but there is a change.

    According to the back of this envelope here, the weight change from raising a kilogram by one metre would be
    about equivalent to reducing its mass by about 3 parts in 10^7, i.e. 300 micrograms. The article says the measured loss was around 50 micrograms. So I guess there is equivalent sensitive enough to measure that.

    Unless I was off by a few orders of magnitude...

  3. It must not lose mass! by EmbeddedJanitor · · Score: 4, Insightful
    Who cares if it loses weight. It just must not lose mass. kg is a unit of **mass**, not weight.

    --
    Engineering is the art of compromise.