All this week, the origin and continued preservation of five of our favorite standard units of measure
By Sam KeanPosted 11.05.2010 at 3:58 pm 9 Comments
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, redefining, and re-redefining them over the ages.
The kilogram really sticks in the craw of metrologists. Six of the seven fundamental units of the metric system have "operational" definitions—you can define them purely in words, by describing a physical process that produces something of exactly one meter, or whatever. But the kilogram has resisted all attempts to define it that way.