Following my retirement, we have closed our company for new business.

Please do not hesitate to contact me directly, our email portal remains open and I would be delighted to hear from you and provide ongoing support or advice.

Richard Thomson

Companies represented up to the end of December 2023. Please now contact them directly.

k-Space Associates, Inc.
Phone: +1 (734) 426-7977

Phone: +49 8761 76 24 0

Saturday 13 November 2010

But perhaps silicon?

The kilogram is the only one of the SI’s seven base units still defined in terms of a material artefact - a 130-year-old platinum-iridium cylinder maintained at the International Bureau of Weights and Measures in France. The US National Institute of Standards and Technology (NIST, nist 1) is working on a proposal that defines the kilogram in terms of the Planck constant h which is expressed in units containing the kilogram. Work at NIST such as the watt balance experiment (nist 2) and determinations of the mass of one mole of silicon atoms offer new ways of determining an accurate value of h, thereby contributing to a more reliable definition of the kilogram.

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