Gram | |
---|---|

The mass of this pen cap is about 1 gram | |

General information | |

Unit system | UCUM base unit and CGS unit |

Unit of | Mass |

Symbol | g |

Conversions | |

1 g in ... | ... is equal to ... |

SI base units | 10^{−3} kilograms |

CGS units | 1 gram |

Imperial units U.S. customary | 0.0353 ounces |

The **gram** (alternative spelling: **gramme**;^{ [1] } SI unit symbol: **g**) is a metric system unit of mass.

- Official SI symbol
- History
- Uses
- Conversion factors
- Comparisons
- See also
- Notes
- References
- External links

Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre [1 cm^{3} ], and at the temperature of melting ice"^{ [2] } (later at 4 °C, the temperature of maximum density of water). However, in a reversal of reference and defined units, a gram is now defined as one thousandth of the SI base unit, the kilogram, or 1×10^{−3} kg, which itself is defined by the International Bureau of Weights and Measures, not in terms of grams, but by taking the fixed numerical value of the Planck constant h to be 6.62607015×10^{−34} kg⋅m^{2}⋅s^{−1}.^{ [3] }^{ [4] }

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 g" to stand for "640 grams" in the English language. The SI does not support the use of abbreviations such as "gr" (which is the symbol for grains),^{ [5] }^{:C-19} "gm" ("g⋅m" is the SI symbol for gram-metre) or "Gm" (the SI symbol for gigametre).

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. Its definition remained that of the weight (*poids*) of a cubic centimetre of water.^{ [6] }^{ [7] }

French *gramme* was taken from the Late Latin term * gramma*. This word—ultimately from Greek γράμμα (

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

The gram is today the most widely used unit of measurement for non-liquid ingredients in cooking and grocery shopping worldwide.^{ [11] }^{ [12] }

Most standards and legal requirements for nutrition labels on food products require relative contents to be stated per 100 g of the product, such that the resulting figure can also be read as a percentage by weight.

- 1 gram (g) = 15.4323583529 grains (gr)
- 1 grain (gr) = 0.06479891 grams (g)
- 1 avoirdupois ounce (oz) = 28.349523125 grams (g)
- 1 troy ounce (ozt) = 31.1034768 grams (g)
- 100 grams (g) = 3.527396195 ounces
- 1 gram (g) = 5 carats (ct)
- 1 gram (g) = 8.98755179×10
^{13}joules (J) (by mass–energy equivalence) - 1 undecimogramme = 1 "eleventh-gram" = 10
^{−11}grams in the historic quadrant–eleventh-gram–second system (QES system) a.k.a. hebdometre–undecimogramme–second system (HUS system) (HUS system)^{ [13] } - 500 grams (g) = 1 Jin in the Chinese units of measurement.

- 1 gram is roughly equal to 1 small paper clip or pen cap.
- The Japanese 1 yen coin has a mass of one gram,
^{ [14] }lighter than the British penny (3.56 g), the United States cent (2.5 g), the Euro cent (2.30 g), and the 5 cent Australian coins (2.80 g).

- ↑ 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.
^{ [9] }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. - ↑ 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*

**Conversion of units** is the conversion between different units of measurement for the same quantity, typically through multiplicative **conversion factors**.

The **kilogram** is the base unit of mass in the International System of Units (SI), the current metric system, 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.

The **litre** or **liter** is a metric unit of volume. It is equal to 1 cubic decimetre (dm^{3}), 1000 cubic centimetres (cm^{3}) or 0.001 cubic metre (m^{3}). 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 **Metre Convention**, also known as the **Treaty of the Metre**, is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations. The treaty created the International Bureau of Weights and Measures (BIPM), an intergovernmental organization under the authority of the General Conference on Weights and Measures (CGPM) and the supervision of the International Committee for Weights and Measures (CIPM), that coordinates international metrology and the development of the metric system.

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 **lb _{m}**,

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.

The **Avogadro constant** (*N*_{A} or *L*) is the proportionality factor that relates the number of constituent particles (usually molecules, atoms or ions) in a sample with the amount of substance in that sample. Its SI unit is the reciprocal mole, and it is defined as *N*_{A} = 6.02214076×10^{23} mol^{−1}. It is named after the Italian scientist Amedeo Avogadro.Although this is called Avogadro's constant (or number), he is not the chemist who determined its value. Stanislao Cannizzarro explained this number four years after Avogadro's death while at the Karlsruhe Congress in 1860.

**Metrology** is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France, when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the Bureau International des Poids et Mesures (BIPM) was established by the Metre Convention. This has evolved into the International System of Units (SI) as a result of a resolution at the 11th Conference Generale des Poids et Mesures (CGPM) in 1960.

**Troy weight** is a system of units of mass that originated in 15th-century England, and is primarily used in the precious metals industry. The Troy weights are the grain, the pennyweight, the troy ounce, and the troy pound. The troy grain is equal to the grain-unit of the avoirdupois system, the troy ounce is heavier than the avoirdupois ounce, yet the troy pound is lighter than the avoirdupois pound.

* Centi-* is a unit prefix in the metric system denoting a factor of one hundredth. Proposed in 1793 and adopted in 1795, the prefix comes from the Latin

* Milli-* is a unit prefix in the metric system denoting a factor of one thousandth (10

* Deci-* is a decimal unit prefix in the metric system denoting a factor of one tenth. Proposed in 1793 and adopted in 1795, the prefix comes from the Latin

**Quintus Remmius Palaemon** or **Quintus Rhemnius Fannius Palaemon** was a Roman grammarian and a native of Vicentia. He lived during the reigns of Emperors Tiberius and Claudius.

**Mesures usuelles** were a French system of measurement introduced by Napoleon I in 1812 to act as compromise between the metric system and traditional measurements. The system was restricted to use in the retail industry and continued in use until 1840, when the laws of measurement from the 1795 and 1799 were reinstituted.

France has a unique history of units of measurement due to the radical decision to invent and adopt the metric system after the French Revolution.

The **grave** is the unit of mass used in the first metric system which was implemented in France in 1793. In 1795, the grave was renamed as the kilogram.

The **hectare** is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm^{2}), or 10,000 m^{2}, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about 0.405 hectare and one hectare contains about 2.47 acres.

The **history of the metric system** began during the Age of Enlightenment with measures of length and weight derived from nature, along with their decimal multiples and fractions. The system became the standard of France and Europe within half a century. Other dimensions with unity ratios were added, and the system went on to be adopted across the world.

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".

The following outline is provided as an overview of and topical guide to the **metric system** – various loosely related systems of measurement that trace their origin to the decimal system of measurement introduced in France during the French Revolution.

- ↑ "Weights and Measures Act 1985 (c. 72)".
*The UK Statute Law Database*. Office of Public Sector Information. Archived from the original on 12 September 2008. Retrieved 26 January 2011.§92.

- ↑ "Décret relatif aux poids et aux mesures" (in French). 1795. Archived from the original on 25 February 2013.
- ↑
*Draft Resolution A "On the revision of the International System of units (SI)" to be submitted to the CGPM at its 26th meeting (2018)*(PDF) - ↑ Decision CIPM/105-13 (October 2016). The day is the 144th anniversary of the Metre Convention.
- ↑ National Institute of Standards and Technology (October 2011). Butcher, Tina; Cook, Steve; Crown, Linda et al. eds. "Appendix C – General Tables of Units of Measurement" Archived 2016-06-17 at the Wayback Machine (PDF).
*Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices*Archived 2016-08-23 at the Wayback Machine . NIST Handbook.**44**(2012 ed.). Washington, D.C.: U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology. ISSN 0271-4027. OCLC OCLC 58927093. Retrieved 30 June 2012. - ↑ "Décret relatif aux poids et aux mesures du 18 germinal an 3 (7 avril 1795)" [Decree of 18 Germinal, year III (April 7, 1795) regarding weights and measures].
*Grandes lois de la République*(in French). Digithèque de matériaux juridiques et politiques, Université de Perpignan. Archived from the original on 10 May 2013. Retrieved 3 November 2011. - ↑ 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), p. 70 Archived 2015-04-02 at the Wayback Machine . The*metre*(*mètre*) on which this definition depends was itself defined as the ten-millionth part of a quarter of Earth's meridian, given in traditional units as 3*pieds*, 11.44*lignes*(a*ligne*being the 12th part of an*pouce*(inch), or the 144th part of a*pied*. - ↑ Charlton T. Lewis, Charles Short,
*A Latin Dictionary*s.v. "gramma" Archived 2015-07-17 at the Wayback Machine , 1879 - ↑ Knorr, Wilbur R. (1996). "Carmen de ponderibus et mensuris". In Hornblower, Simon; Spawforth, Antony (eds.).
*The Oxford Classical Dictionary*(3rd ed.). Oxford: Oxford University Press. p. 292. ISBN 019866172X. - ↑ Henry George Liddell. Robert Scott.
*A Greek-English Lexicon*(revised and augmented edition, Oxford, 1940) s.v. γράμμα Archived 2015-07-17 at the Wayback Machine , 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. - ↑ Pat Chapman (2007).
*India Food and Cooking: The Ultimate Book on Indian Cuisine*. London: New Holland Publishers (UK) Ltd. p. 64. ISBN 978-1845376192 . Retrieved 20 November 2014.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).

- ↑ Gisslen, Wayne (2010).
*Professional Cooking, College Version*. New York: Wiley. p. 107. ISBN 0-470-19752-8 . Retrieved 20 April 2011.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.

- ↑ "System of Measurement Units - Engineering and Technology History Wiki".
*ethw.org*. Archived from the original on 29 April 2018. Retrieved 29 April 2018. - ↑ "Circulating Coin Designs". Japan Mint. Archived from the original on 18 September 2009. Retrieved 7 March 2010.

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