Editing Gram

{{Short description|Metric unit of mass}}
{{About|the unit of mass||Gram (disambiguation)|and|Grams (disambiguation)}}
{{Redirect|Gramme}}
{{Use dmy dates |date=July 2020}}
{{Infobox unit
| name          = gram
| image         = [[File:One-yen coin mass.jpg|300px]]
| caption       = The mass of this Japanese [[one yen coin]] is 1.00 gram. A [[weight scale]] such as this can give an accurate reading of mass for many objects (see [[Weight vs. mass]]).
| standard      = [[SI]]
| quantity      = [[Mass]]
| symbol        = g
| namedafter    = 
| units1        = [[SI base unit]]s
| inunits1      = 10<sup>−3</sup> [[kilogram]]s
| units2        = [[CGS unit]]s
| inunits2      = 1 gram
| units3        = [[Imperial units]]<br/>[[United States customary units|U.S. customary]]
| inunits3      = {{convert|1.000000|g|oz|disp=out|lk=out|abbr=off}}
| units4        = [[Atomic mass unit]]s
| inunits4      = {{val|6.02214076|e=23|u=[[Dalton (unit) | Da]]}}
}}
The '''gram''' (originally '''gramme''';<ref>{{cite web |url = http://www.statutelaw.gov.uk/content.aspx?activeTextDocId=2191980 |title = Weights and Measures Act 1985 (c. 72) |work = The UK Statute Law Database |publisher = Office of Public Sector Information |quote = §92. |access-date = 2011-01-26 |url-status = live |archive-url = https://web.archive.org/web/20080912105635/http://www.statutelaw.gov.uk/content.aspx?activeTextDocId=2191980 |archive-date = 2008-09-12 }}</ref> [[SI]] unit symbol '''g''') is a [[Physical unit|unit]] of [[mass]] in the [[International System of Units]] (SI) equal to one thousandth of a [[kilogram]].

Originally defined in 1795 as "the absolute [[weight]] of a [[volume]] of pure [[water]] equal to [[Cube (algebra)|the cube]] of the hundredth part of a [[metre]] [1 [[Cubic centimetre|cm<sup>3</sup>]]&#93;, and at [[Melting point of water|the temperature]] of [[Melting point|melting]] [[ice]]",<ref>{{cite web |url=http://smdsi.quartier-rural.org/histoire/18germ_3.htm |title=Décret relatif aux poids et aux mesures |language=fr |archive-url=https://web.archive.org/web/20130225163152/http://smdsi.quartier-rural.org/histoire/18germ_3.htm |archive-date=2013-02-25 |year=1795 }}</ref> the defining temperature (≈0&nbsp;°C) was later changed to 4&nbsp;°C, the temperature of maximum density of water.

By the late 19th century, there was an effort to make the [[Base unit (measurement)|base unit]] the [[kilogram]] and the gram a derived unit. In 1960, the new [[International System of Units]] defined a ''gram'' as one one-thousandth of a kilogram (i.e., one gram is {{val|1e-3|u=kg}}). The kilogram, [[2019 revision of the SI|as of 2019]], is defined by the [[International Bureau of Weights and Measures]] from the fixed numerical value of the [[Planck constant]] ({{mvar|h}}).<ref name="draft-resolution-A">
{{citation
 |title=Draft Resolution A "On the revision of the International System of units (SI)" to be submitted to the CGPM at its 26th meeting (2018)
 |url=https://www.bipm.org/utils/en/pdf/CGPM/Draft-Resolution-A-EN.pdf
 |access-date=17 May 2020
 |archive-date=29 April 2018
 |archive-url=https://web.archive.org/web/20180429025229/https://www.bipm.org/utils/en/pdf/CGPM/Draft-Resolution-A-EN.pdf
 |url-status=dead
}}</ref><ref>[http://www.bipm.org/en/committees/cipm/meeting/105.html Decision CIPM/105-13 (October 2016)] {{Webarchive|url=https://web.archive.org/web/20170824095943/http://www.bipm.org/en/committees/cipm/meeting/105.html |date=24 August 2017 }}.  The day is the 144th anniversary of the [[Metre Convention]].</ref>

== Official SI symbol ==
The only unit symbol for gram that is recognised by the [[International System of Units]] (SI) is "g" following the numeric value with a space, as in "640&nbsp;g" to stand for "640 grams" in the English language. The SI disallows use of abbreviations such as "gr" (which is the symbol for [[Grain (unit)|grains]]),<ref name="NIST">National Institute of Standards and Technology (October 2011). Butcher, Tina; Cook, Steve; Crown, Linda et al. eds. [https://www.nist.gov/pml/wmd/pubs/upload/AppC-12-hb44-final.pdf "Appendix C – General Tables of Units of Measurement"] {{webarchive|url=https://web.archive.org/web/20160617040949/http://www.nist.gov/pml/wmd/pubs/upload/AppC-12-hb44-final.pdf |date=2016-06-17 }} (PDF). [https://www.nist.gov/pml/wmd/pubs/h44-12.cfm ''Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices''] {{webarchive|url=https://web.archive.org/web/20160823052024/http://www.nist.gov/pml/wmd/pubs/h44-12.cfm |date=2016-08-23 }}. NIST Handbook. '''44''' (2012 ed.). Washington, D.C.: U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology. [[International Standard Serial Number|ISSN]] [http://www.worldcat.org/issn/0271-4027 0271-4027] {{Webarchive|url=https://web.archive.org/web/20221225104227/https://www.worldcat.org/search?q=n2:0271-4027 |date=25 December 2022 }}. [[Online Computer Library Center|OCLC]] {{OCLC|58927093}}. Retrieved 30 June 2012.</ref>{{rp|C-19}} "gm" ("g⋅m" is the SI symbol for gram-[[metre]]) or "Gm" (the SI symbol for [[Giga-|giga]]metre).

== History ==
The word ''gramme'' was adopted by the French [[National Convention]] in its 1795 decree revising the metric system as replacing the ''gravet'' (introduced in 1793 simultaneously with a base measure called [[Grave (unit)|''grave'']], of which ''gravet'' was a subdivision). Its definition remained that of the weight of a cubic centimetre of water.<ref>
{{cite web
 |url         = http://mjp.univ-perp.fr/france/1793mesures.htm
 |title       = Décret relatif aux poids et aux mesures du 18 germinal an 3 (7 avril 1795)
 |language    = fr
 |trans-title = Decree of 18 Germinal, year III (April 7, 1795) regarding weights and measures
 |work        = Grandes lois de la République
 |publisher   = Digithèque de matériaux juridiques et politiques, Université de Perpignan
 |access-date  = November 3, 2011
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20130510150614/http://mjp.univ-perp.fr/france/1793mesures.htm
 |archive-date = May 10, 2013
}}
</ref><ref>Convention nationale, décret du 1er août 1793, ed. Duvergier, ''Collection complète des lois, décrets, ordonnances, règlemens avis du Conseil d'état, publiée sur les éditions officielles du Louvre'', vol. 6 (2nd ed. 1834), [https://books.google.com/books?id=0mYZAAAAYAAJ&pg=PA70 p. 70] {{webarchive|url=https://web.archive.org/web/20150402120318/https://books.google.ch/books?id=0mYZAAAAYAAJ&pg=PA70 |date=2015-04-02 }}.
The ''metre'' (''mètre'') on which this definition depends was itself defined as the ten-millionth part of a quarter of Earth's [[Meridian (geography)|meridian]], given in [[Units of measurement in France before the French Revolution|traditional units]] as 3 ''[[foot (unit)|pieds]]'',  11.44 ''lignes'' (a ''ligne'' being the 12th part of an ''pouce'' (inch), or the 144th part of a ''pied''.</ref>

French ''gramme'' was taken from the [[Late Latin]] term ''{{lang|la|gramma}}''. This word—ultimately from Greek {{lang|grc|γράμμα}} (''grámma''), "letter"—had adopted a specialised meaning in [[Late Antiquity]] of "one twenty-fourth part of an ounce" (two [[oboli]]),<ref>Charlton T. Lewis, Charles Short, ''A Latin Dictionary'' [https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dgramma2 s.v. "gramma"] {{webarchive|url=https://web.archive.org/web/20150717095000/http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0059:entry=gramma2 |date=2015-07-17 }}, 1879</ref> corresponding to about 1.14 modern grams. This use of the term is found in the ''carmen de ponderibus et mensuris'' ("poem about weights and measures") composed around 400 AD.{{efn|The date and authorship of this Late Latin didactic poem are both uncertain; it was attributed to [[Priscian]] but is now attributed to Rem(m)ius Favinus/Flav(in)us.<ref>{{cite book|last1=Knorr|first1=Wilbur R.|editor1-last=Hornblower|editor1-first=Simon|editor2-last=Spawforth|editor2-first=Antony|title=The Oxford Classical Dictionary.|date=1996|publisher=Oxford University Press|location=Oxford|isbn=019866172X|page=[https://archive.org/details/isbn_9780198661726/page/292 292]|edition=3rd|chapter=Carmen de ponderibus et mensuris|url-access=registration|url=https://archive.org/details/isbn_9780198661726/page/292}}</ref> The poem's title is reflected in the French phrase ''poids et mesures'' ("weights and mesures") in the title of the 1795 National Convention decree, ''Décret relatif aux poids et aux mesures'' that introduced the gram, and indirectly in the name of the [[General Conference on Weights and Measures]] responsible for the modern definition of the metric units.}}
There is also evidence that the Greek {{lang|grc|γράμμα}} was used in the same sense at around the same time, in the 4th century, and survived in this sense into [[Medieval Greek]],<ref>Henry George Liddell. Robert Scott. ''[[A Greek-English Lexicon]]'' (revised and augmented edition, Oxford, 1940)   [https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=gra/mma s.v. γράμμα] {{webarchive|url=https://web.archive.org/web/20150717095023/http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dgra%2Fmma |date=2015-07-17 }}, citing the 10th-century work ''[[Geoponica]]'' and a 4th-century papyrus edited in L. Mitteis, ''Griechische Urkunden der Papyrussammlung zu Leipzig'', vol. i (1906), 62 ii 27.</ref> while the Latin term died out in [[Medieval Latin]] and was recovered in [[Renaissance]] scholarship.{{efn|In the Renaissance, the ''carmen de ponderibus et mensuris'' was received as a work of the 1st-century grammarian [[Remmius Palaemon]] edited in 1528 by Johann Setzer of [[Hagenau]], together with works by [[Celsius]], [[Priscian]] and Johannes Caesarius; ''Aurelij Cornelij Celsi, De re medica, libri octo eruditissimi. Q. Sereni Samonici Praecepta medica, uersibus hexametris. Q. Rhemnij Fannij Palaemonis, De ponderibus [et] mensuris, liber rarus [et] utilissimus''}}

The gram was the base unit of mass in the 19th-century [[centimetre–gram–second system of units]] (CGS). The CGS system coexisted with the [[MKS system of units|metre–kilogram–second system of units]] (MKS), first proposed in 1901, during much of the 20th century, but the gram was displaced by the [[kilogram]] as the base unit for mass when the MKS system was chosen for the [[SI base units]] in 1960.

== Uses ==
[[File:Amphetamine.jpg|thumb|One gram of [[amphetamine]]s (the unit often used for street retail)]]
The gram is the most widely used unit of measurement for non-liquid ingredients in cooking and grocery shopping worldwide.<ref>{{cite book |author=Pat Chapman |title=India Food and Cooking: The Ultimate Book on Indian Cuisine |date=2007 |publisher=New Holland Publishers (UK) Ltd |location=London |isbn=978-1845376192 |page=64 |url=https://books.google.com/books?id=orHWFRMKf4EC&pg=PA64 |access-date=2014-11-20 |quote=Most of the world uses the metric system to weigh and measure. This book puts metric first, followed by imperial because the US uses it (with slight modifications which need not concern us). }}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{cite book |author=Gisslen, Wayne |title=Professional Cooking, College Version |publisher=Wiley |location=New York |year=2010 |page=107 |isbn=978-0-470-19752-3 |access-date=2011-04-20 |url=https://books.google.com/books?id=N5el9CYbEP0C&pg=PA107 |quote=The system of measurement used in the United States is complicated. Even when people have used the system all their lives, they still sometimes have trouble remembering things like how many fluid ounces are in a quart or how many feet are in a mile. ... The United States is the only major country that uses almost exclusively the complex system of measurement we have just described.}}</ref> Liquid ingredients are often measured by [[volume]] rather than mass.

Many standards and legal requirements for [[nutrition label]]s on food products require relative contents to be stated per 100&nbsp;g of the product, such that the resulting figure can also be read as a percentage.

{{anchor|Eleventh-gram}}

== Conversion factors ==
[[File:Wellcome Foundation Object Wellcome L0044963.jpg|thumb|A container of [[GSK_plc#Burroughs_Wellcome|Wellcome]]-brand cocaine, containing 1 avoirdupois [[ounce]] or 28.3 grams (note the non-standard abbreviation ''gm.'').]]
* 1 gram (g) ≈ {{convert|1.000000|g|gr|disp=out|abbr=off|lk=on}} (gr)
* 1 grain (gr) ≈ {{convert|1.000000|gr|g|disp=out|abbr=off}}
* 1 [[Avoirdupois|avoirdupois ounce]] (oz) ≈ {{convert|1.000000|oz|g|disp=out|abbr=off}}
* 1 [[troy ounce]] (ozt) = 31.1034768 g (exact, by definition)
* 100 grams (g) ≈ {{convert|100.0000|g|oz|disp=out|abbr=off}} (oz)
* 1 carat (ct) = 0.2 grams
* 1 gamma (γ) = 10<sup>−6</sup> grams<ref>5th SI Brochure (1985), p. 78</ref><ref>{{cite journal|title=NIST Special Publication 811 – NIST Guide to the SI, Chapter 5: Units Outside the SI|journal=NIST |date=28 January 2016 |url=https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-5-units-outside-si|access-date=2022-12-10|archive-date=12 August 2016|archive-url=https://web.archive.org/web/20160812121900/http://nist.gov/pml/pubs/sp811/sec05.cfm|url-status=live}}</ref>
* 1 undecimogramme = 1 "eleventh-gram" = 10<sup>−11</sup> grams in the historical quadrant–eleventh-gram–second system ([[QES]] system) a.k.a. hebdometre–undecimogramme–second system (HUS system) <ref>{{cite web|url=http://ethw.org/System_of_Measurement_Units|title=System of Measurement Units – Engineering and Technology History Wiki|website=ethw.org|date=24 April 2012 |access-date=29 April 2018|url-status=live|archive-url=https://web.archive.org/web/20180429231359/http://ethw.org/System_of_Measurement_Units|archive-date=29 April 2018}}</ref>
* 500 grams (g) = 1 jin in the [[Chinese units of measurement]].

== Comparisons ==
* 1 gram is roughly equal to the mass of 1 small paper clip or pen cap.
* The Japanese [[1 yen coin]] has a mass of 1 gram,<ref name="Mint">{{cite web|url=http://www.mint.go.jp/eng/kids/circulating_c.html |title=Circulating Coin Designs |publisher=Japan Mint |access-date=7 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20090918202540/http://www.mint.go.jp/eng/kids/circulating_c.html |archive-date=18 September 2009 }}</ref> lighter than the [[Penny (British decimal coin)|British penny]] (3.56&nbsp;g), the [[Penny (United States coin)|United States penny]] (2.5&nbsp;g), the [[1 cent Euro coins|Euro cent]] (2.30&nbsp;g), and the [[Coins of Australia|Australian 5 cent coin]] (2.80&nbsp;g).

== See also ==
* [[Conversion of units]]
* [[Duella]]
* [[Gold gram]]
* [[Orders of magnitude (mass)]]

== Notes ==
{{notelist}}

== References ==
{{reflist}}

{{CGS units}}
{{Authority control}}

[[Category:Units of mass]]
[[Category:Centimetre–gram–second system of units]]