Redefining the Kilogram

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07/17/2015

Jul. 17, 2015

Redefining the Kilogram

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All the scales in the world—from those at your local deli to the big ones at the junkyard—are ultimately calibrated against a 125-year-old chunk of metal in a vault on the outskirts of Paris. Its mass is the definition of a kilogram. There’s just one problem: That chunk of metal seems to be losing weight. We talk to Derek Muller, creator of the Veritasium science education series, about the race to redefine the kilo in less slippery terms—and what a near-perfect silicon crystal sphere has to do with it. And Jon Pratt, an engineer at the National Institute of Standards and Technology, tells us about his team’s alternative “watt balance” strategy to lock down the kilo in terms of Planck’s constant.

Produced by Christopher Intagliata, Senior Producer

Produced by Elah Feder, Intern, Radio

Guests

Jon Pratt
Leader, Fundamental Electrical Measurements Group
National Institute of Standards and Technology
Gaithersburg, Maryland
Derek Muller
Creator of Veritasium
Los Angeles, California

Discussion

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Code:
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line 23: 		my(@sel) = &Database::SelectClause('GLOBAL','record all ""');
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line 66: &doEval();
line 67: 1;