As cheat sheets go, it is a long one. Every four years, a task force of the Committee on Data for Science and Technology (CODATA), headquartered in Paris, releases a short-hand description of the ...

The fundamental constants that govern the laws of nature are being determined with increasing accuracy. A new paper outlines the proceedings from this year's Workshop on the Determination of the ...

The redefinition of several physical base units planned for 2018 requires precise knowledge of the values of certain fundamental physical constants. Scientists are working hard to meet the deadlines ...

If scientists had sacred objects, this would be one of them: a single, closely guarded 137-year-old cylinder of metal, housed in a vault outside of Paris. It is a prototype that precisely defines a ...

All change: work on the redefinition of the kilogram was carried out using a Kibble balance. (Courtesy: BIPM) The redefinition of four units of the International System of Units (SI) will come into ...

Tampa, Fla. – A fundamental number that affects the color of light emitted by atoms as well as all chemical interactions has not changed in more than 7 billion years, according to observations by a ...

Weighty matters: a platinum-iridium kilogram belonging to the US National Institute of standards and Technology. (Courtesy: J.L. Lee/NIST) Metrologists and policy-makers from 60 countries around the ...

THROUGHOUT MUCH of human history, man has been the measure of many, if not all, things. Lengths were divided up into feet, palms, spans and smaller units derived from the human hand. Other measures ...

Mathematical constants are built from the fabric of mathematics and can be determined a priori: Pi is based on the shape of a circle and can be calculated from numerous equations, e is from the growth ...