Kilogram Gets Controversial; Why Not Split the Difference?

Posted by timothy on Sunday January 30, 2011 @11:07AM from the try-a-different-scale dept.

gbrumfiel writes "As Slashdot has noted, the kilogram has a problem. The SI unit is officially defined as the weight of a 130-year-old platinum-iridium cylinder in France. But the physical object appears to be getting lighter. Scientists want to replace the cylinder with a new standard based on Planck's constant, but two experiments designed to facilitate the switch keep coming up with different results. Now one researcher is proposing a solution: just average the two diverging experiments and use that value as the official definition. Not everyone thinks that averaging the two amounts to sound research: 'Deciding to just average these two results would be perfectly proper mathematics, but it would not be science,' says Michael Hart, a physicist at the University of Manchester, UK."

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Re:Can't the kilogram be derived from other SI uni by norpy · 2011-01-30 12:30 · Score: 4, Insightful

A gram is not the mass of 1 cubic centimeter of water. It is 1/1000 of the weight of that lump of metal in france!

There are a ton of posts above arguing over that, and you can't use that to define mass because it is affected by pressure. Pressure has a mass component so it ultimately becomes circular.