The early history of chemistry has many interesting stories. Just consider the problems scientists had 200 years ago as they tried to figure out some of the most basic ideas of chemistry. It was clear ...

This video is about the mole, the unit of measurement for the number of particles in a substance. The mole is the unit for amount of substance. The number of particles in a substance can be found ...

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 ...

It’s October 23, or Mole Day for chemistry enthusiasts. From 6:02 a.m. to 6:02 p.m. students and teachers celebrate their love of chemistry with Avogadro’s number — 6.02 x 10^23, a unit of measurement ...

Today, October 23, is Mole Day -- the unofficial holiday when we celebrate Amedeo Avogadro and his contributions to molecular theory. In 1811, Avogadro hypothesized that given two volumetrically ...

This discussion paper, circulated in advance of the 17th meeting of the Consultative Committee for Amount of Substance, addresses the proposed redefinition of the mole in terms of a fixed numerical ...

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 ...

Relics in the form of rods, rulers, and weights go back thousands of years, suggesting that people have long cared about standardized measurements. Today, the International System of Units(SI) defines ...

It doesn’t happen too often, but after a vote that took place earlier today near Paris, science textbooks really will have to be rewritten. At the Congress Chamber in the Palace of Versailles, ...