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Redefining The Kilogram: Turning A Piece Of Metal Into A Math Problem

NPR

Published December 12, 2018 at 11:25 AM CST

In this photo taken Wednesday, Oct. 17, 2018., a replica of the International Prototype Kilogram is pictured at the International Bureau of Weights and Measures, in Sevres, near Paris. The golf ball-sized metal cylinder at the heart of the world's system for measuring mass is heading into retirement. (Christophe Ena/AP)

In November, scientists and diplomats voted unanimously to redefine the kilogram. They decided the kilogram will no longer be based on a physical piece of metal, but on a math problem instead.

Here & Now‘s Jeremy Hobson learns more about what this change means from Patrick Abbott, a physicist at the National Institute of Science and Technology (@usnistgov).