Original kilogram losing mass, status, scientists say

The squat metal cylinder weighs exactly 1 kilogram, as it should. It is the world's definition of mass, the standard kilogram against which all others are judged. Once the scientists know how many atoms are in 1 kilogram, that number could redefine the kilogram standard. The apparatus works by...

Full description

Saved in:
Bibliographic Details
Published inKnight Ridder Tribune News Service p. 1
Main Author Witze, Alexandra
Format Newsletter
LanguageEnglish
Published Washington Tribune Content Agency LLC 22.11.2002
Subjects
Davis, Richard
De Bievre, Paul
Kibble, Bryan
Steiner, Richard
Online AccessGet full text

Cover

More Information
Summary:The squat metal cylinder weighs exactly 1 kilogram, as it should. It is the world's definition of mass, the standard kilogram against which all others are judged. Once the scientists know how many atoms are in 1 kilogram, that number could redefine the kilogram standard. The apparatus works by balancing the force of gravity pulling down on a 1-kilogram mass against an upward-pulling magnetic force. The device can indirectly define the kilogram because all the other units measured -- such as time, length, voltage and resistance -- are already precisely defined.