Ajay Kumar: Created a new article

2023-08-28T15:44:40Z

Created a new article

New page

{{short description|Metric unit of mass equivalent to 1000 kilograms or 1 megagram}}
{{About|the metric unit of mass|other ton units|Ton|other uses of tonne|Tonne (disambiguation)|other uses of "megagram"|Megagram (geometry)}}
{{Redirect|Gigatons|the album by Pearl Jam|Gigaton}}
{{Infobox unit
| bgcolor =
| name = Tonne Megagram
| image = File:A 1-tonne weight (geograph 6511341).jpg
| caption = A one-tonne (1000-kilogram) concrete block
| quantity = mass
| symbol = t Mg
| extralabel = In [[SI unit]]s:
| extradata = {{val|1000|u=kg}}
}}
The '''tonne''' ({{IPAc-en|audio=En-us-tonne.ogg|t|ʌ|n}} or {{IPAc-en|t|ɒ|n}}; symbol: '''t''') is a unit of mass equal to 1000 [[kilogram]]s. It is a [[International System of Units#Non-SI units accepted for use with SI|non-SI unit accepted for use with SI]]. It is also referred to as a '''metric ton''' to distinguish it from the [[ton|non-metric unit]]s of the [[short ton]] ([[United States customary units]]) and the [[long ton]] ([[Imperial units|British imperial units]]). It is equivalent to approximately 2204.6 [[international avoirdupois pound|pound]]s, 1.102 short tons, and 0.984 long tons. The official SI unit is the '''megagram''' (symbol: '''Mg'''), a less common way to express the same amount.

==Symbol and abbreviations==
The [[International_Bureau_of_Weights_and_Measures|BIPM]] symbol for the tonne is t, adopted at the same time as the unit in 1879.<ref name=bippy>[http://www.bipm.org/en/si/si_brochure/chapter4/table6.html Table 6] {{webarchive|url=https://web.archive.org/web/20091001100650/http://www.bipm.org/en/si/si_brochure/chapter4/table6.html |date=2009-10-01 }}. BIPM. Retrieved on 2011-07-10.</ref> Its use is also official for the metric ton in the United States, having been adopted by the United States [[National Institute of Standards and Technology]] (NIST).<ref name=fedreg/><ref>[[National Institute of Standards and Technology|NIST]] [https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.330-2019.pdf Special Publication 330, 2019 edition] states "The name of the unit with symbol t and defined according to 1 t = 103 kg is called 'metric ton' rather than 'tonne.'".</ref> It is a symbol, not an abbreviation, and should not be followed by a [[period (punctuation)|period]]. Use of [[Letter_case#Minuscule|minuscule]] letter case is significant, and use of other letter combinations can lead to ambiguity. For example, T, MT, mT, are the SI symbols for the [[Tesla (unit)|tesla]], megatesla, and millitesla, respectively, while Mt and mt are SI-compatible symbols for the megatonne (one teragram) and millitonne (one kilogram). If describing [[TNT equivalent]] units of energy, one megatonne of TNT is equivalent to approximately 4.184 [[petajoule]]s.

==Origin and spelling==

In English, ''tonne'' is an established spelling alternative to ''metric ton''.<ref>{{cite web |url=https://www.oed.com/view/Entry/203217?redirectedFrom=tonne#eid |title=tonne, n |work=[[OED]] |access-date=6 August 2021}}</ref> In the United States and United Kingdom, tonne is usually pronounced the same as ton ({{IPAc-en|t|ʌ|n}}), but the final "e" can also be pronounced, i.e. "'''tunnie'''" ({{IPAc-en|ˈ|t|ʌ|n|i}}).<ref>The Oxford English dictionary 2nd ed. lists both /tʌn/ and /ˈtʌni/</ref> In Australia, the common and recommended pronunciation is {{IPAc-en|t|ɒ|n}}.<ref>{{cite book |title= Macquarie Dictionary|edition= fifth |year= 2009|publisher= Macquarie Dictionary Publishers Pty Ltd|location= Sydney}}</ref><ref>{{cite news |date=1972-11-21 |title=How To Pronounce Metrics Units (advertisement by Australian Metric Conversion Board) |work=The Age |page=14 |access-date=2021-11-01 |url=https://news.google.com/newspapers?id=9ihVAAAAIBAJ&sjid=3ZADAAAAIBAJ&pg=6434%2C4864047}}</ref> In the United States, ''metric ton'' is the name for this unit used and recommended by NIST;<ref name="fedreg">[http://lamar.colostate.edu/~hillger/laws/63fr40333.pdf Metric System of Measurement: Interpretation of the International System of Units for the United States] {{Webarchive|url=https://web.archive.org/web/20080409102714/http://lamar.colostate.edu/~hillger/laws/63fr40333.pdf|date=2008-04-09}} (PDF). See corrections in the Errata section of [http://lamar.colostate.edu/~hillger/laws/nist-interpretation.html] {{Webarchive|url=https://web.archive.org/web/20080418115704/http://lamar.colostate.edu/~hillger/laws/nist-interpretation.html|date=2008-04-18}}.</ref> an unqualified mention of a ''ton'' almost invariably refers to a [[short ton]] of {{convert|2000|lb|kg|sigfig=3|comma=off}} and to a lesser extent to a [[long ton]] of {{convert|2240|lb|kg|sigfig=3|comma=off}}, the ''tonne'' is rarely used in speech or writing. Both terms are acceptable in Canadian usage.

''Ton'' and ''tonne'' are both derived from a [[Germanic languages|Germanic]] word in general use in the [[North Sea]] area since the [[Middle Ages]] (cf. [[Old English]] and [[Old Frisian]] ''tunne'', [[Old High German]] and [[Medieval Latin]] {{Lang|la-x-medieval|tunna}}, [[German language|German]] and [[French language|French]] ''tonne'') to designate a large cask, or ''tun''.<ref>{{OEtymD|tonne}}</ref> A full tun, standing about a metre high, could easily weigh a tonne.

The spelling ''tonne'' pre-dates the introduction of the SI in 1960; it has been used with this meaning in France since 1842,<ref>{{cite web|url=http://atilf.atilf.fr/dendien/scripts/tlfiv4/showps.exe?p=combi.htm;java=no;|title=Recherche d'un mot|website=atilf.atilf.fr}}</ref> when there were no metric prefixes for multiples of 106 and above, and is now used as the standard spelling for the metric mass measurement in most [[English language|English]]-speaking countries.<ref>{{cite web
|url=http://www.nmo.bis.gov.uk/Docs/Legislation/Units%20of%20Measurement/Gnotes%20for%20public%20sector%20on%20use%20of%20metric.pdf
|title=Guidance Note on the use of Metric Units of Measurement by the Public Sector
|year=2007
|publisher=National Measurement Office
|access-date=2010-02-13
|url-status=dead
|archive-url=http://webarchive.nationalarchives.gov.uk/20110207120946/http://www.nmo.bis.gov.uk/Docs/Legislation/Units%20of%20Measurement/Gnotes%20for%20public%20sector%20on%20use%20of%20metric.pdf
|archive-date=2011-02-07
}} "Tonne" is listed under "The Principal Metric Units of Measurement" on p. 7.
</ref><ref>{{cite web
|url= http://www.comlaw.gov.au/ComLaw/Legislation/LegislativeInstrumentCompilation1.nsf/framelodgmentattachments/35F21696B4C9E27CCA2575EC001FA5D1
|title= National Measurement Regulations 1999 {{pipe}}|year=1999
|publisher=Australian Government
|access-date=2010-02-13}} "Tonne" is listed under Schedule 1, Part 3 as a non-SI unit of measurement used with SI units of measurement.</ref><ref>{{cite web |url= http://www.maf.govt.nz/statistics/forestry/annual/nzstats2000/appendix/append4.htm|title= Appendix 4: Units of Measurement and Conversion Factors|publisher= MAF (Ministry of Agriculture and Forestry (New Zealand))|access-date=2010-02-13}}</ref><ref>{{cite web|url=http://www.gazette.gc.ca/archives/p2/1999/1999-11-10/html/sor-dors430-eng.html|title=Canada Gazette|date=1998–2007|publisher=Government of Canada|access-date=2010-02-13|quote=The Corporation shall pay to producers selling and delivering wheat produced in the designated area to the Corporation the following sums certain per tonne basis...|archive-date=2011-07-06|archive-url=https://web.archive.org/web/20110706181616/http://www.gazette.gc.ca/archives/p2/1999/1999-11-10/html/sor-dors430-eng.html|url-status=dead}}</ref> In the United States, the unit was originally referred to using the [[French language|French]] words ''millier'' or ''tonneau'',<ref>Act of July 28, 1866, codified in {{UnitedStatesCode|15|205}}</ref> but these terms are now obsolete.<ref name="FR1998">{{cite journal |title=Metric System of Measurement: Interpretation of the International System of Units for the United States |journal=[[Federal Register]] |date=July 28, 1998 |volume=63 |issue=144 |id=63 FR 40333 |page=40338 |url=http://physics.nist.gov/cuu/pdf/SIFedReg.pdf |url-status = dead |archive-url=https://web.archive.org/web/20111015081850/http://physics.nist.gov/cuu/pdf/SIFedReg.pdf |archive-date=October 15, 2011}}</ref> The British imperial and United States customary units comparable to the tonne are both spelled ''ton'' in English, though they differ in mass.

==Conversions==
One tonne is equivalent to:
*In [[kilogram]]s: {{val|1000|u=kilograms (kg)}} by definition.<ref>{{SIbrochure9th}}</ref>
*In [[gram]]s: {{val|1000000|u=grams (g)}} or 1 megagram (Mg). Megagram is the corresponding official SI unit with the same mass. Mg is distinct from mg, milligram.
*In [[Pound (mass)|pounds]]: Exactly {{sfrac|1000|0.453{{thin space}}592{{thin space}}37}} pounds (lb) by definition of the pound,<ref name=nbs447>{{Cite book | title=Weights and measures standards of the United States – A brief history | year=1976 | url=http://physics.nist.gov/Pubs/SP447/contents.html | first=L.E. | last=Barbrow | author2=Judson, L.V. | url-status=dead | archive-url=https://web.archive.org/web/20080511153143/http://physics.nist.gov/Pubs/SP447/contents.html | archive-date=2008-05-11 }}</ref> or approximately {{val|2204.622622|u=lb}}.<ref name=NGS>{{cite web | url= http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf | author = United States National Bureau of Standards | title= Notices "Refinement of values for the yard and the pound" | date= 1959-06-25 | access-date= 2006-08-12}}</ref>
*In [[short ton]]s: Exactly {{sfrac|1|0.907{{thin space}}184{{thin space}}74}} short tons (ST), or approximately {{val|1.102311311}} ST.
**One short ton is exactly {{val|0.90718474|u=t}}.<ref name="NISTUnits">National Institute of Standards and Technology. {{cite book |date=October 2013 |chapter=Appendix C – General Tables of Units of Measurement |chapter-url=https://www.nist.gov/pml/wmd/pubs/upload/appc-14-hb44-final.pdf |editor1-last=Butcher |editor1-first=Tina |editor2-last=Crown |editor2-first=Linda |editor3-last=Harshman |editor3-first=Rick |editor4-last=Williams |editor4-first=Juana |title=Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices |url=https://www.nist.gov/pml/wmd/pubs/hb44-14.cfm |series=NIST Handbook |volume=44 |edition=2014 |location=Washington, D.C. |publisher=U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology |page=C-13 |issn=0271-4027 |oclc=58927093 |access-date=10 December 2013}}</ref>
*In [[long ton]]s: Exactly {{sfrac|1|1.016{{thin space}}046{{thin space}}9088}} long tons (LT), or approximately {{val|0.9842065276}} LT.
**One long ton is exactly {{val|1.0160469088|u=t}}.<ref name="NISTUnits" />

A tonne is the mass of one [[cubic metre]] of pure water: at 4 °C one thousand [[litre]]s of pure water has an absolute mass of one tonne.<ref>To within 0.003%.</ref>

==Derived units==
As a non-SI unit, the use of SI metric prefixes with the tonne does not fall within the SI standard. For multiples of the tonne, it is more usual to speak of thousands or millions of tonnes. Kilotonne, megatonne, and gigatonne are more usually used for the energy of nuclear explosions and other events in [[TNT equivalent|equivalent mass of TNT]], often loosely as approximate figures. When used in this context, there is little need to distinguish between metric and other tons, and the unit is spelled either as ''ton'' or ''tonne'' with the relevant prefix attached.<ref>The Oxford English Dictionary 2nd ed. gives both megaton and megatonne and adds "The unit may be calculated in either imperial or metric tons; the form megatonne generally implies the metric unit". The use for energy is the first definition; use for mass or weight is the third definition.</ref>
{|class="wikitable" style="text-align:center"
|-
! colspan=2 | Tonnes
! colspan=2 | Grams
! colspan=3 | Equivalents*
|-
! Name !! Symbol
! Name !! Symbol
! Tonnes (t) !! US/short tons (ST)† !! Imperial/long tons (LT)†
|-
| tonne ||t
| megagram ||Mg
|1 t || {{convert|1|t|ST|disp=output number only|sigfig=5|comma=gaps}} ST || {{convert|1|t|LT|disp=output number only|sigfig=5|comma=gaps}} LT
|-
| kilotonne ||ktǂ
| gigagram ||Gg
| 1000 t || {{convert|1000|t|ST|disp=output number only|sigfig=5|comma=gaps}} ST || {{convert|1000|t|LT|disp=output number only|sigfig=5|comma=gaps}} LT
|-
| [[Orders of magnitude (mass)#106 to 1011 kg|megatonne]] ||Mt
| teragram ||Tg
| 1 million t || {{convert|1|t|ST|disp=output number only|sigfig=5|comma=gaps}} million ST || {{convert|1000000|t|LT|disp=output number only|sigfig=5|comma=gaps}} LT
|-
| gigatonne||Gt
| petagram||Pg
| 1 billion t || {{convert|1|t|ST|disp=output number only|sigfig=5|comma=gaps}} billion ST || {{convert|1000|t|LT|disp=output number only|sigfig=5|comma=gaps}} million LT
|-
|}

*The equivalent units columns use the [[short scale]] large-number naming system currently used in most English-language countries, e.g. 1 billion = 1000 million = {{val|1,000,000,000}}. 
†Values in the equivalent short and long tons columns are [[Rounding|rounded]] to five [[significant figures]]. See [[#Conversions|Conversions]] for exact values. 
ǂThough non-standard, the symbol "kt" is also used (instead of the standard symbol "kn") for [[knot (unit)|knot]], a unit of speed for aircraft and sea-going vessels, and should not be confused with kilotonne.

==Alternative usages==
===Metric ton units=== 
A '''metric ton unit''' (mtu) can mean 10 kg (approximately 22 lb) within metal trading, particularly within the United States. It traditionally referred to a metric ton of ore containing 1% (i.e. 10 kg) of metal.<ref>{{cite web|url=http://www.emis.platts.com/thezone/guides/platts/metals/conversion.html|title=Platt's Metals Guide to Specifications – Conversion Tables|date=8 September 2008|url-status=bot: unknown|archive-url=https://web.archive.org/web/20080908055702/http://www.emis.platts.com/thezone/guides/platts/metals/conversion.html|archive-date=8 September 2008}}</ref><ref>[http://www.unc.edu/~rowlett/units/dictM.html How Many? A Dictionary of Units of Measurement] {{Webarchive|url=https://web.archive.org/web/20110904024909/http://www.unc.edu/~rowlett/units/dictM.html |date=2011-09-04 }}. Unc.edu. Retrieved on 2011-07-10.</ref>
The following excerpt from a mining geology textbook describes its usage in the particular case of tungsten:
{{quote|
Tungsten concentrates are usually traded in metric tonne units (originally designating one tonne of ore containing 1% of WO3, today used to measure WO3 quantities in 10 kg units. One metric tonne unit (mtu) of tungsten (VI) contains 7.93 kilograms of tungsten.|Walter L Pohl, ''Economic Geology: Principles and Practices'', English edition, 2011, p 183.}}

In the case of [[uranium]], ''MTU'' is sometimes used in the sense of ''metric ton of uranium'' (1,000 kg).<ref>[http://www-pub.iaea.org/MTCD/publications/PDF/rwmp-3/REFERENCE.pdf Reference.Pdf]. (PDF) . Retrieved on 2011-07-10.</ref><ref>"[http://www.hanford.gov/rl/uploadfiles/ea/ea1319/ea1319.html Glossary] {{Webarchive|url=https://web.archive.org/web/20100314163903/http://www.hanford.gov/rl/uploadfiles/ea/ea1319/ea1319.html |date=2010-03-14 }}". (June 2000). ''Disposition of Surplus Hanford Site Uranium, Hanford Site, Richland, Washington''. US Department of Energy.</ref><ref>"[http://www.y12.doe.gov/library/acronyms/letter.php?index=M Acronyms] {{Webarchive|url=https://web.archive.org/web/20130312082236/http://www.y12.doe.gov/library/acronyms/letter.php?index=M |date=2013-03-12 }}". Y-12 National Security Complex.</ref><ref>[https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0544/r4/ NRC Collection of Abbreviations (NUREG-0544, Rev. 4), United States Nuclear Regulatory Commission]. Nrc.gov (2011-03-13). Retrieved on 2011-07-10.</ref>

===Use of mass as proxy for energy===
{{Main article|TNT equivalent}}
The ''tonne of [[trinitrotoluene]] (TNT)'' is used as a proxy for energy, usually of explosions (TNT is a common [[high explosive]]). Prefixes are used: kiloton(ne), megaton(ne), gigaton(ne), especially for expressing [[nuclear weapon yield]], based on a [[Fuel value|specific combustion energy]] of TNT of about 4.2 [[megajoule|MJ]]/[[kilogram|kg]] (or one [[calorie|thermochemical calorie]] per [[milligram]]). Hence, 1 t TNT = {{abbr|approx.|approximately}} 4.2 [[Gigajoule|GJ]], 1 [[kiloton|kt]] TNT = approx. 4.2 [[Terajoule|TJ]], 1 Mt TNT = approx. 4.2 [[Petajoule|PJ]].

The SI unit of energy is the [[joule]]. One tonne of TNT is approximately equivalent to 4.2 gigajoules.

In the [[petroleum industry]] the [[tonne of oil equivalent]] (toe) is a [[units of energy|unit of energy]]: the amount of energy released by burning one tonne of [[crude oil]], approximately 42 GJ. There are several slightly different definitions. This is ten times as much as a tonne of TNT because atmospheric oxygen is used.

===Unit of force===
Like the [[gram]] and the kilogram, the tonne gave rise to a (now obsolete) force unit of the same name, the tonne-force, equivalent to about 9.8 [[Newton_(unit)#Kilonewtons|kilonewtons]]. The unit is also often called simply "tonne" or "metric ton" without identifying it as a unit of force. In contrast to the tonne as a mass unit, the tonne-force is not accepted for use with SI.

==See also==
* [[Metre–tonne–second system of units]]
* [[Orders of magnitude (mass)]]
* [[Ton]]
** [[Tonnage]]
** [[Ton (volume)]]

== Notes and references ==
{{Reflist}}

== External links ==
*NIST Special Publication 811, [https://web.archive.org/web/20100216211152/http://physics.nist.gov/Pubs/SP811/ ''Guide for the Use of the International System of Units (SI)'']

{{SI units}}

{{authority control}}

[[Category:Non-SI metric units]]
[[Category:Units of mass]]

Tonne - Revision history

Ajay Kumar: Created a new article