The Kilogram Crisis

International Bureau of Weights and Measures:

The international kilogram conundrum, we no longer know what a kilogram is.

Oh sure we have a rough approximation, but the real deal is very puzzling.

Check out this article. By Jia-Rui Chong, Los Angeles Times Staff Writer April 17, 2008

A copy of the international prototype kilogram under its protective casing. The real prototype, known as Le Grand K, is rarely removed from its temperature- and humidity-controlled vault to avoid damage.

In the more than a century since 'perfect' platinum-iridium cylinders were first used as the world's kilogram standards, their weights have mysteriously fluctuated.