History of Weight

	Revision 20 . . December 5, 2001 5:13 am by AxelBoldt
	Revision 19 . . December 5, 2001 4:08 am by The Anome [updated SI units link target and text]
	Revision 18 . . December 5, 2001 3:49 am by Josh Grosse [Combined two mentions of SI]
	Revision 17 . . December 5, 2001 2:29 am by Ed Poor [reinserted correct information, let's not fight, I also combined 2 sentences]
	Revision 16 . . December 5, 2001 2:23 am by AxelBoldt [Please don't delete correct information.]
	Revision 15 . . December 5, 2001 1:58 am by Ed Poor [add metric system & terms, reduced weighty discussion of this massive controversy]
	Revision 14 . . December 5, 2001 1:50 am by AxelBoldt [+NIST official usage of "to weigh"]
	Revision 13 . . December 4, 2001 1:13 pm by Josh Grosse [More or less a rewrite, to bring in line with Talk and new introduction.]
	Revision 12 . . December 4, 2001 8:09 am by Dreamyshade [less wordy, still could use some more improvement :)]
	Revision 11 . . December 4, 2001 7:43 am by Ed Poor [attempt to reconcile, but still far too wordy]
	Revision 10 . . (edit) December 3, 2001 12:34 pm by Josh Grosse
	Revision 9 . . December 3, 2001 12:32 pm by (logged).109.250.xxx [note two different definitons of pound]
	Revision 8 . . December 3, 2001 12:21 pm by Josh Grosse
	Revision 7 . . December 3, 2001 12:16 pm by Josh Grosse
	Revision 6 . . (edit) December 3, 2001 12:14 pm by KamikazeArchon
	Revision 5 . . (edit) December 3, 2001 12:14 pm by KamikazeArchon
	Revision 4 . . December 3, 2001 12:11 pm by (logged).109.250.xxx [CGPM reccomends definition of weight as force, not mass]
	Revision 3 . . (edit) December 3, 2001 12:07 pm by KamikazeArchon
	Revision 2 . . December 3, 2001 11:43 am by (logged).109.250.xxx [wikify]
	Revision 1 . . December 3, 2001 11:42 am by (logged).109.250.xxx [clear up common confusions about weight vs. mass]

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Difference (from prior major revision) (no other diffs)

Changed: 3c3

Related to the historical identification of mass and weight, the pound has been used both as a unit of mass and as a unit of force. In the United States, United Kingdom, and elsewhere, the pound is now officially defined as a unit of mass. The corresponding force is called a pound-force, and similarly the weight of a kilogram of material on Earth is called a kilogram-force. However the use of pounds to measure forces is still very common in physics and engineering, and in derivative units like p.s.i. (pounds per square inch). In most countries scientists have adopted SI units, which use kilograms for mass and newtons for force non-interchangeably.

Related to the historical identification of mass and weight, the pound has been used both as a unit of mass and as a unit of force. In the United States, United Kingdom, and elsewhere, the pound is now officially defined as a unit of mass. The corresponding force is called a pound-force, and similarly the weight of a kilogram of material on Earth is called a kilogram-force. However the use of pounds to measure forces is still common in engineering, and it occurs in derived units like p.s.i. (pounds per square inch). In most countries, scientists have adopted SI units, which use kilograms for mass and newtons for force non-interchangeably.