Gram
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| Unit system: | SI derived unit |
| Quantity: | Mass |
| Symbol: | g |
| Dimension: | M |
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| 1 g in... | is equal to... |
| SI base units | 10-3 kilograms |
| CGS units | 1 gram |
| U.S. customary | 0.0353 ounces |
The gram (alternative British English spelling: gramme;[1] SI unit symbol: g) (Greek/Latin root grámma) is a metric system unit of mass.
Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre, and at the temperature of melting ice"[2] (later 4 °C), a gram is now defined as one one-thousandth of the SI base unit, the kilogram, or 1×10−3 kg, which itself is defined as being equal to the mass of a physical prototype preserved by the International Bureau of Weights and Measures.
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[edit] Symbol and abbreviations
The International System of Units (SI) unit symbol for the gram is "g" following the numeric value with a space, as in "640 g". While some authors use ad-hoc abbreviations, this creates confusion. For example, the use of abbreviations such as "gm", "Gm", or "GM" for grams could potentially lead to serious errors in health-care settings where accidentally transposing "gm" to "mg" (milligrams) could result in a 1,000 times dosage error. It is therefore important to use "g" as specified in the SI standard to avoid confusion or misunderstanding.
[edit] History
It was the base unit of mass in the original French metric system and the later centimetre-gram-second (CGS) system of units. The word originates from Late Latin gramma – a small weight.
[edit] Uses
The gram is today the most widely used unit of measurement for non-liquid ingredients in cooking and grocery shopping worldwide. For food products that are typically sold in quantities far less than 1 kg, the unit price is normally given per 100 g.
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.
[edit] Conversion factors
- 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)
- 1 gram (g) = 8.98755179×1013 joules (J) (by mass–energy equivalence)
[edit] Comparisons
- 1 gram is roughly equal to 1 small paper clip or pen cap.
- The Japanese 1 yen coin has a mass of one gram.[3] (lighter than the British penny (3.56 g), the United States cent (2.5 g) or the "Euro-cent" (2.30 g)).
[edit] See also
[edit] References
- ^ "Weights and Measures Act 1985 (c. 72)". The UK Statute Law Database. Office of Public Sector Information. Retrieved 2011-01-26. "§92."
- ^ Décret relatif aux poids et aux mesures, 1795
- ^ "Circulating Coin Designs". Japan Mint. Retrieved 7 March 2010.
