Kilogram: Difference between revisions

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imported>Anthony Argyriou
(very basic intro. will clean up later)
 
imported>Anthony Argyriou
(replace much with information from NIST)
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The '''kilogram''' is the [[International System of Units|SI]] unit of [[mass]]. Earlier definitions of units of mass in the metric system started with the [[gram]], which is one-thousandth of a kilogram.  The first definition of a gram was the weight of 1 cm<sup>3</sup> of water at its maximum density (at 4 degrees C); the kilogram was the weight of 1,000 cm<sup>3</sup>, or 1 dm<sup>3</sup> of water. Since then, the kilogram has been defined by the weight of a prototype cylinder kept at [[Sevres, France]].
The '''kilogram''' is the [[International System of Units|SI]] unit of [[mass]].
 
At the end of the 18th century, a kilogram was the mass of a cubic decimeter of water. In 1889, the 1st CGPM sanctioned the international prototype of the kilogram, made of platinum-iridium, and declared: This prototype shall henceforth be considered to be the unit of mass.  
 
The 3d CGPM (1901), in a declaration intended to end the ambiguity in popular usage concerning the word "weight," confirmed that:
<blockquote>The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.</blockquote>

Revision as of 20:45, 14 March 2007

The kilogram is the SI unit of mass.

At the end of the 18th century, a kilogram was the mass of a cubic decimeter of water. In 1889, the 1st CGPM sanctioned the international prototype of the kilogram, made of platinum-iridium, and declared: This prototype shall henceforth be considered to be the unit of mass.

The 3d CGPM (1901), in a declaration intended to end the ambiguity in popular usage concerning the word "weight," confirmed that:

The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.