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 two of the most precise ...

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 ...

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 ...

SCIENTISTS HAVE SPENT the better part of the past four centuries, since the early days of the Enlightenment, discovering the truth about how the natural world works. A critical part of this endeavor ...

The world’s measurement system will be based on updated values for four fundamental constants of nature. A revised SI ( the International System of Units ) based fully on accurate values of these ...

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 ...

The metric system is on track for a mass makeover. In an effort to provide accurate measurements at all scales, scientists are preparing to redefine four basic units by the end of 2018. The shift will ...

How much is a kilogram? It turns out that nobody can say for sure, at least not in a way that won’t change ever so slightly over time. The official kilogram – a cylinder cast 118 years ago from ...

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 ...