Contact: Ben Stein
National Institute of Standards and Technology (NIST)
Caption: In support of a proposal to revise the International System of Units (SI) so that it would be based on constants of nature, NIST efforts such as the watt balance experiment (pictured) offer new ways of determining an accurate value of the Planck constant h, thereby contributing to a definition of the kilogram based on physical constants.
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Related news release: 'Sí' on the new SI: NIST backs proposal for a revamped system of measurement units