All this week, the origin and continued preservation of five of our favorite standard units of measure By Sam Kean Published Nov 5, 2010 11:58 PM EDT ...

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.

News Published: 28 August 1919 Standard of Mass Nature 103, 515 (1919) Cite this article ...

A. 1000 grams B. a standard unit of mass (often ignored in the United States) C. a platinum-iridium cylinder kept in a vault in Sèvres, France D. all of the above The answer is D, of course.

This week, Sam Kean takes a look at some ridiculously precise standards -- the meter, the second, and other international standard units -- and the role that elements have played in defining ...

The unit of mass will no longer be defined by a lone physical object but instead in terms of a universal constant. It was France’s King Louis XVI who, in the late 1700s, got a group of scientists ...

Nevertheless, deriving a unit like a microgram – a billionth of a kilogram – from a 1 kg mass can be cumbersome, particularly in a world of increasingly sensitive scientific measurements.