User:Milton Beychok/Sandbox: Difference between revisions
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A '''tonne''' (t) or '''metric tonne''' (also referred to as a '''metric ton'''), is a measurement of mass equal to 1000 [[kg]], or almost exactly the mass of one [[litre]] of pure [[water]].<ref>The density of air-free water at a [[pressure]] of 1 [[Pressure|atmosphere]]. [http://www.iapws.org/relguide/fundam.pdf Guideline on the Use of Fundamental Physical Constants and Basic Constants of Water] September 2001, The International Association for the Properties of Water and Steam.</ref> It is not an [[SI]] unit but is accepted for use with the SI.<ref>Section 4.1 of [http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf The International System of Units (SI)] (PDF), 8th Edition, 2006</ref> If prefixes were used completely consistently, the SI unit for a tonne would be a "megagram" (Mg, see [[SI prefix]]), but this term is rarely used. Though the spelling ''tonne'' pre-dates the introduction of the SI system in 1960 (it has been used in France for about two and a half centuries{{Fact|date=April 2009}}), it is now used as the standard spelling for the metric mass measurement in some English-speaking countries. The comparable [[Imperial unit|imperial]] and [[United States customary units|US customary]] units are spelled ''ton'' in English. | |||
== References == | |||
{{reflist}} | |||
Revision as of 16:23, 7 May 2009
A tonne (t) or metric tonne (also referred to as a metric ton), is a measurement of mass equal to 1000 kg, or almost exactly the mass of one litre of pure water.[1] It is not an SI unit but is accepted for use with the SI.[2] If prefixes were used completely consistently, the SI unit for a tonne would be a "megagram" (Mg, see SI prefix), but this term is rarely used. Though the spelling tonne pre-dates the introduction of the SI system in 1960 (it has been used in France for about two and a half centuriesTemplate:Fact), it is now used as the standard spelling for the metric mass measurement in some English-speaking countries. The comparable imperial and US customary units are spelled ton in English.
References
- ↑ The density of air-free water at a pressure of 1 atmosphere. Guideline on the Use of Fundamental Physical Constants and Basic Constants of Water September 2001, The International Association for the Properties of Water and Steam.
- ↑ Section 4.1 of The International System of Units (SI) (PDF), 8th Edition, 2006