The kilogram finally has a precise meaning despite defying a rigorous definition for over a century. Delegates of the General Conference on Weights and Measures unanimously voted Nov. 16 in favor of a ...

If several scientists get their way, a 2.2-pound hunk of metal -- the international prototype of the kilogram -- may soon be out of style. Like its six basic-units-of-measurement siblings before it -- ...

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 ...

Electrical or electronic quantities and units are crucial values to know in evaluating and describing the behavior, characteristics and physical properties of a circuit. This quiz can help you recall ...

How much is a kilogram? 1,000 grams. 2.20462 pounds. Or 0.0685 slugs based on the old Imperial gravitational system. But where does this amount actually come from and how can everyone be sure they are ...