Tonne

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tonne
Illustration of One Tonne 2018.07.06.png
One tonne is equal to 1000 kilograms or 1 megagram
General information
Unit system Non-SI unit accepted for use with SI
Unit ofMass
Symbolt
In SI base units:1 t = 1000 kg = 1 Mg

The tonne ( /tʌn/ ( Loudspeaker.svg listen ) or /tɒn/ ; symbol: t) is a non-SI metric unit of mass equal to 1,000  kilograms. [1] It is commonly referred to as a metric ton in the United States. [2] It is equivalent to approximately 2,204.6 pounds, [3] 1.102 short tons (US) or approximately 0.984 long tons (UK). The official SI unit is the megagram (symbol: Mg), a less common way to express the same mass.

Contents

The tonne is derived from the mass of one cubic metre of pure water; at 4 °C one thousand litres of pure water has an absolute mass of one tonne. [4]

Symbol and abbreviations

The BIPM symbol for the tonne is 't', adopted at the same time as the unit in 1879. [5] 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). [6] It is a symbol, not an abbreviation, and should not be followed by a period. Use of majuscule and minuscule letter case is significant, and use of other letter combinations is not permitted and would lead to ambiguity. For example, 'T', 'MT', 'mT', 'Mt', 'mt' are the SI symbols for the tesla, megatesla, millitesla, megatonne (one teragram), and millitonne (one kilogram) respectively. If describing TNT equivalent units of energy, one megatonne of TNT is equivalent to approximately 4.184 petajoules.

Origin and spelling

In French and English, tonne is the correct spelling. It is usually pronounced the same as ton ( /tʌn/ ), but the final "e" can also be pronounced, i.e. "tunnie" ( /ˈtʌnɪ/ ). [7] In Australia, it is also pronounced /tɒn/ . [8] In the United States, metric ton is the name for this unit used and recommended by NIST; [6] an unqualified mention of a ton almost invariably refers to a short ton of 2,000 pounds (907 kg), and tonne is rarely used in speech or writing. Both terms are acceptable in Canadian usage.

Before metrication in the UK the unit used for most purposes was the Imperial ton of 2,240  pounds avoirdupois or 20 hundredweight (usually referred to as the long ton in the US), equivalent to approximately 1,016 kg, differing by about 1.6% from the tonne. The UK Weights and Measures Act 1985 explicitly excluded from use for trade certain imperial units, including the ton, unless the item being sold or the weighing equipment being used was weighed or certified prior to 1 December 1980, and even then only if the buyer was made aware that the weight of the item was measured in imperial units. [9] [ full citation needed ] [10] [11]

Ton and tonne are both derived from a 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 tunna, German and French tonne) to designate a large cask, or tun. [12] A full tun, standing about a metre high, could easily weigh a tonne. An English tun (an old wine cask volume measurement equivalent to approximately 954 litres) of wine has a relative mass of approximately 954  kg if full of pure water, a little less for wine.

The spelling tonne pre-dates the introduction of the SI in 1960; it has been used with this meaning in France since 1842, [13] 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-speaking countries. [14] [15] [16] [17] In the United States, the unit was originally referred to using the French words millier or tonneau, [18] but these terms are now obsolete. [2] The Imperial and US customary units comparable to the tonne are both spelled ton in English, though they differ in mass.

Conversions

One tonne is equivalent to:

Derived units

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 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 spelt either as ton or tonne with the relevant prefix attached. [21]

TonnesGramsEquivalents*
MultipleNameSymbolMultipleNameSymbolTonnes (t)Kilograms (kg)Grams (g)US/short tons (ST)Imperial/long tons (LT)
100tonnet106megagramMg1 t1,000 kg1 million g1.1023 ST0.98421 LT
103kilotonnektǂ109gigagramGg1,000 t1 million kg1 billion g1,102.3 ST984.21 LT
106 megatonne Mt1012teragramTg1 million t1 billion kg1 trillion g1.1023 million ST984,210 LT
109gigatonneGt1015petagramPg1 billion t1 trillion kg1 quadrillion g1.1023 billion ST984.21 million LT
1012teratonneTt1018exagramEg1 trillion t1 quadrillion kg1 quintillion g1.1023 trillion ST984.21 billion LT
1015petatonnePt1021zettagramZg1 quadrillion t1 quintillion kg1 sextillion g1.1023 quadrillion ST984.21 trillion LT
1018exatonneEt1024yottagramYg1 quintillion t1 sextillion kg1 septillion g1.1023 quintillion ST984.21 quadrillion LT

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

Alternative usage

A metric ton unit (mtu) can mean 10 kg (approximately 22 lns) within metal (e.g. tungsten, manganese) trading, particularly within the US. It traditionally referred to a metric ton of ore containing 1% (i.e. 10 kg) of metal. [22] [23] The following excerpt from a mining geology textbook describes its usage in the particular case of tungsten:

"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.)

Tungsten is also known as wolfram and has the atomic symbol W.

In the case of uranium, the acronym MTU is sometimes considered to be metric ton of uranium, meaning 1,000 kg. [24] [25] [26] [27]

A gigatonne is a unit of mass often used by the coal mining industry to assess and define the extent of a coal reserve.

Use of mass as proxy for energy

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 specific combustion energy of TNT of about 4.2  MJ/kg (or one thermochemical calorie per milligram). Hence, 1 t TNT = approx. 4.2  GJ, 1 kt TNT = approx. 4.2  TJ, 1 Mt TNT = approx. 4.2  PJ.

The SI unit of energy is the joule. Assuming that a TNT explosion releases 1,000 small (thermochemical) calories per gram (approx. 4.2  kJ/g), one tonne of TNT is approx. equivalent to 4.2 gigajoules.

In the petroleum industry the tonne of oil equivalent (toe) is a unit of energy: the amount of energy released by burning one tonne of crude oil, approx, 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 kilonewtons: a unit 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 or metric ton-force is not acceptable for use with SI, partly because it is not an exact multiple of the SI unit of force, the newton.

See also

Notes and references

  1. 1 2 "The International System of Units (SI), 9th edition" (PDF). 2019. p. 145. Retrieved December 31, 2019.
  2. 1 2 "Metric System of Measurement: Interpretation of the International System of Units for the United States" (PDF). Federal Register . 63 (144): 40338. July 28, 1998. 63 FR 40333. Archived from the original (PDF) on October 15, 2011.
  3. United States National Bureau of Standards (1959-06-25). "Notices "Refinement of values for the yard and the pound"" (PDF). Retrieved 2006-08-12.
  4. To within 0.003%.
  5. Table 6 Archived 2009-10-01 at the Wayback Machine . BIPM. Retrieved on 2011-07-10.
  6. 1 2 Metric System of Measurement: Interpretation of the International System of Units for the United States Archived 2008-04-09 at the Wayback Machine (PDF). See corrections in the Errata section of Archived 2008-04-18 at the Wayback Machine .
  7. The Oxford English dictionary 2nd ed. lists both /tʌn/ and /ˈtʌnɪ/
  8. Macquarie Dictionary (fifth ed.). Sydney: Macquarie Dictionary Publishers Pty Ltd. 2009.
  9. A Dictionary of Weights, Measures, and Units, edited by Donald Fenna, Oxford University Press
  10. "Weights and Measures Act 1985". Section 8(1), Act No. 72 of 30 October 1985 . Retrieved 11 Apr 2016.
  11. "Weights and Measures Act 1985". Schedule 11(13–14), Act No. 72 of 30 October 1985 . Retrieved 11 Apr 2016.
  12. Harper, Douglas. "tonne". Online Etymology Dictionary .
  13. "Recherche d'un mot". atilf.atilf.fr.
  14. "Guidance Note on the use of Metric Units of Measurement by the Public Sector" (PDF). National Measurement Office. 2007. Archived from the original (PDF) on 2011-02-07. Retrieved 2010-02-13. "Tonne" is listed under "The Principal Metric Units of Measurement" on p. 7.
  15. "National Measurement Regulations 1999 |". Australian Government. 1999. Retrieved 2010-02-13. "Tonne" is listed under Schedule 1, Part 3 as a non-SI unit of measurement used with SI units of measurement.
  16. "Appendix 4: Units of Measurement and Conversion Factors". MAF (Ministry of Agriculture and Forestry (New Zealand)). Retrieved 2010-02-13.
  17. "Canada Gazette". Government of Canada. 1998–2007. Retrieved 2010-02-13. 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...
  18. Act of July 28, 1866, codified in 15 U.S.C.   § 205
  19. Barbrow, L.E.; Judson, L.V. (1976). Weights and measures standards of the United States – A brief history. Archived from the original on 2008-05-11.
  20. 1 2 National Institute of Standards and Technology. Butcher, Tina; Crown, Linda; Harshman, Rick; Williams, Juana, eds. (October 2013). "Appendix C – General Tables of Units of Measurement" (PDF). Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices. NIST Handbook. 44 (2014 ed.). Washington, D.C.: U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology. p. C-13. ISSN   0271-4027. OCLC   58927093 . Retrieved 10 December 2013.
  21. 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.
  22. "Platt's Metals Guide to Specifications – Conversion Tables". 8 September 2008. Archived from the original on 8 September 2008.CS1 maint: BOT: original-url status unknown (link)
  23. How Many? A Dictionary of Units of Measurement. Unc.edu. Retrieved on 2011-07-10.
  24. Reference.Pdf. (PDF) . Retrieved on 2011-07-10.
  25. "Glossary". (June 2000). Disposition of Surplus Hanford Site Uranium, Hanford Site, Richland, Washington. US Department of Energy.
  26. "Acronyms". Y-12 National Security Complex.
  27. NRC Collection of Abbreviations (NUREG-0544, Rev. 4), United States Nuclear Regulatory Commission. Nrc.gov (2011-03-13). Retrieved on 2011-07-10.

Related Research Articles

The joule is a derived unit of energy in the International System of Units. It is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of the force's motion through a distance of one metre. It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).

Kilogram SI unit of mass

The kilogram is the base unit of mass in the metric system, formally the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering, and commerce worldwide, and is often simply called a kilo in everyday speech.

Litre unit of volume accepted for use with the SI

The litre or liter is a non-SI unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre. A cubic decimetre occupies a volume of 10 cm × 10 cm × 10 cm and is thus equal to one-thousandth of a cubic metre.

The pound or pound-mass is a unit of mass used in the imperial, United States customary and other systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly 0.45359237 kilograms, and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol is lbm, #, and or ″̶.

International System of Units Modern form of the metric system

The International System of Units is the modern form of the metric system. It is the only system of measurement with an official status in nearly every country in the world. It comprises a coherent system of units of measurement starting with seven base units, which are the second, metre, kilogram, ampere, kelvin, mole, and candela. The system allows for an unlimited number of additional units, called derived units, which can always be represented as products of powers of the base units. Twenty-two derived units have been provided with special names and symbols. The seven base units and the 22 derived units with special names and symbols may be used in combination to express other derived units, which are adopted to facilitate measurement of diverse quantities. The SI system also provides twenty prefixes to the unit names and unit symbols that may be used when specifying power-of-ten multiples and sub-multiples of SI units. The SI is intended to be an evolving system; units and prefixes are created and unit definitions are modified through international agreement as the technology of measurement progresses and the precision of measurements improves.

A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit. While all metric prefixes in common use today are decadic, historically there have been a number of binary metric prefixes as well. Each prefix has a unique symbol that is prepended to the unit symbol. The prefix kilo-, for example, may be added to gram to indicate multiplication by one thousand: one kilogram is equal to one thousand grams. The prefix milli-, likewise, may be added to metre to indicate division by one thousand; one millimetre is equal to one thousandth of a metre.

The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of mass. Its original use as a measurement of volume has continued in the capacity of cargo ships and in terms such as the freight ton. Recent specialised uses include the ton as a measure of energy and for truck classification. It is also a colloquial term.

United States customary units are a system of measurements commonly used in the United States. The United States customary system developed from English units which were in use in the British Empire before the U.S. became an independent country. However, the United Kingdom's system of measures was overhauled in 1824 to create the imperial system, changing the definitions of some units. Therefore, while many U.S. units are essentially similar to their imperial counterparts, there are significant differences between the systems.

Metric system Metre-based systems of measurement

A metric system is a system of measurement that succeeded the decimalised system based on the metre introduced in France in the 1790s. The historical development of these systems culminated in the definition of the International System of Units (SI), under the oversight of an international standards body.

The pound of force or pound-force is a unit of force used in some systems of measurement including English Engineering units and the Foot–pound–second system. Pound-force should not be confused with foot-pound, a unit of energy, or pound-foot, a unit of torque, that may be written as "lbf⋅ft"; nor should these be confused with pound-mass, often simply called pound, which is a unit of mass.

Orders of magnitude (mass) Orders of magnitude (mass)

To help compare different orders of magnitude, the following lists describe various mass levels between 10−59 kg and 1052 kg.

The quintal or centner is a historical unit of mass in many countries which is usually defined as 100 base units, such as pounds or kilograms. It is a traditional unit of weight in France, Portugal, and Spain and their former colonies. It is commonly used for grain prices in wholesale markets in India, where 1 quintal = 100 kg.

Long ton, also known as the imperial ton or displacement ton, is the name for the unit called the "ton" in the avoirdupois system of weights or Imperial system of measurements. It was standardised in the thirteenth century. It is used in the United Kingdom and several other British Commonwealth of Nations countries alongside the mass-based metric tonne defined in 1799, as well as in the United States for bulk commodities.

The kilogram-force, or kilopond, is a gravitational metric unit of force. It is equal to the magnitude of the force exerted on one kilogram of mass in a 9.80665 m/s2 gravitational field. Therefore, one kilogram-force is by definition equal to 9.80665 N. Similarly, a gram-force is 9.80665 mN, and a milligram-force is 9.80665 μN.

The short ton is a mass measurement unit equal to 2,000 pounds-mass. Its usage is confined to the United States, where it is known as simply a common ton.

A system of measurement is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Systems of measurement in use include the International System of Units (SI), the modern form of the metric system, the imperial system, and United States customary units

The foot–pound–second system or FPS system is a system of units built on three fundamental units: the foot for length, the (avoirdupois) pound for either mass or force, and the second for time.

The units of transportation measurement describes the unit of measurement used to measure the quantity and traffic of transportation used in transportation statistics, planning, and their related fields.

Introduction to the metric system

The metric system was developed during the French Revolution to replace the various measures previously used in France. The metre is the unit of length in the metric system and was originally based on the dimensions of the earth, as far as it could be measured at the time. The litre, is the unit of volume and was defined as one thousandth of a cubic metre. The metric unit of mass is the kilogram and it was defined as the mass of one litre of water. The metric system was, in the words of French philosopher Marquis de Condorcet, "for all people for all time".

Imperial and US customary measurement systems English (pre 1824), Imperial (post 1824) and US Customary (post 1776) units of measure

The Imperial and US customary measurement systems are both derived from an earlier English system of measurement which in turn can be traced back to Ancient Roman units of measurement, and Carolingian and Saxon units of measure.