There is a common misconception among educators, and even some metrologists, that the Avogadro constant _N_~A~ is (or should be) a pure number, and not a constant of dimension *N*^–1^ (where *N* is ...

This release is available in German. A milestone in the international Avogadro project coordinated by the Physikalisch-Technische Bundesanstalt (PTB) has been reached: With the aid of a single crystal ...

WASHINGTON, D.C., July 14, 2015 -- An ongoing international effort to redefine the kilogram by 2018 has been helped by recent efforts from a team researchers from Italy, Japan and Germany to correlate ...

A new definition of the kilogram is required, an international team of scientists contends. The current one is imprecise, they say, because it is not linked to an unvarying property of nature. The ...

Scientists are hoping to redefine the kilogram by counting the number of atoms in the roundest objects ever made. So for the first time, a kilogram would relate to a universal constant, which by ...

The kilogram is the only SI base unit that is still defined by a material object – a piece of platinum-iridium alloy kept in a vault in Sèvres, near Paris. All the other units are related to atomic or ...

I MUST plead guilty to the charge of not having made a very deep search of the older literature in connexion with the evaluation of ‘Avogadro's Number’. This name has only come into general use in ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

The kilogram may finally get a break from its yo-yo diet. An international team of scientists is closer to redefining the unit of mass based on fundamental constants, instead of a piece of metal in ...