Litre
litre | |
---|---|
litron | |
Conversions | |
1 L in ... | ... is equal to ... |
SI base unit | 10−3 m3 |
U.S. customary | ≈ 0.264 gallon |
The litre (
The original French
One litre of liquid water has a mass of almost exactly one kilogram, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice (0 °C).[4] Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact.[5]
Definition
A litre is a cubic
From 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density (+3.98 °C)[
A litre is equal in volume to the millistere, an obsolete non-SI metric unit formerly customarily used for dry measure.
Explanation
Litres are most commonly used for items (such as fluids and solids that can be poured) which are measured by the capacity or size of their container, whereas cubic metres (and derived units) are most commonly used for items measured either by their dimensions or their displacements. The litre is often also used in some calculated measurements, such as density (kg/L), allowing an easy comparison with the density of water.
One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at about 4 °C. It follows, therefore, that 1000th of a litre, known as one millilitre (1 mL), of water has a mass of about 1 g; 1000 litres of water has a mass of about 1000 kg (1 tonne or megagram). This relationship holds because the gram was originally defined as the mass of 1 mL of water; however, this definition was abandoned in 1799 because the density of water changes with temperature and, very slightly, with pressure.
It is now known that the density of water also depends on the isotopic ratios of the oxygen and hydrogen atoms in a particular sample. Modern measurements of Vienna Standard Mean Ocean Water, which is pure distilled water with an isotopic composition representative of the average of the world's oceans, show that it has a density of 0.999975±0.000001 kg/L at its point of maximum density (3.984 °C) under one standard atmosphere (101.325 kPa) of pressure.[6]
SI prefixes applied to the litre
The litre, though not an official SI unit, may be used with
l
and the digit 1
may be confused.[8]Multiple | Name | Symbols | Equivalent volume | ||
---|---|---|---|---|---|
10−30 L | quectolitre | ql | qL | 103 pm3 | thousand cubic picometres |
10−27 L | rontolitre | rl | rL | 106 pm3 | million cubic picometres |
10−24 L | yoctolitre | yl | yL | nm3 | cubic nanometre |
10−21 L | zeptolitre | zl | zL | 103 nm3 | thousand cubic nanometres |
10−18 L | attolitre | al | aL | 106 nm3 | million cubic nanometres |
10−15 L | femtolitre | fl | fL | μm3 | cubic micrometre |
10−12 L | picolitre | pl | pL | 103 μm3 | thousand cubic micrometres |
10−9 L | nanolitre | nl | nL | 106 μm3 | million cubic micrometres |
10−6 L | microlitre | μl | μL | mm3 | cubic millimetre |
10−3 L | millilitre | ml | mL | cm3 | cubic centimetre |
10−2 L | centilitre | cl | cL | 101 cm3 | ten cubic centimetres |
10−1 L | decilitre | dl | dL | 102 cm3 | hundred cubic centimetres |
100 L | litre | l | L | dm3 | cubic decimetre |
101 L | decalitre | dal | daL | 101 dm3 | ten cubic decimetres |
102 L | hectolitre | hl | hL | 102 dm3 | hundred cubic decimetres |
103 L | kilolitre | kl | kL | m3 | cubic metre |
106 L | megalitre | Ml | ML | dam3 | cubic decametre, 1 million litres |
109 L | gigalitre | Gl | GL | hm3 | cubic hectometre |
1012 L | teralitre | Tl | TL | km3 | cubic kilometre |
1015 L | petalitre | Pl | PL | 103 km3 | thousand cubic kilometres |
1018 L | exalitre | El | EL | 106 km3 | million cubic kilometres |
1021 L | zettalitre | Zl | ZL | Mm3 | cubic megametre |
1024 L | yottalitre | Yl | YL | 103 Mm3 | thousand cubic megametres |
1027 L | ronnalitre | Rl | RL | 106 Mm3 | million cubic megametres |
1030 L | quettalitre | Ql | QL | Gm3 | cubic gigametre |
Non-metric conversions
Approx. value of 1 litre in non-metric units | Non-metric unit | Equivalent in litres | ||
---|---|---|---|---|
≈ 0.87987699 | 1 imperial quart | ≡ 1.1365225 L | ||
≈ 1.056688 | 1 US quart | ≡ 0.946352946 L | ||
≈ 1.75975399 | 1 imperial pint | ≡ 0.56826125 L | ||
≈ 2.11337641 | 1 US pint | ≡ 0.473176473 L | ||
≈ 0.21996925 | 1 imperial gallon | ≡ 4.54609 L | ||
≈ 0.2641720523 | 1 US gallon | ≡ 3.785411784 L | ||
≈ 0.0353146667 | 1 cubic foot | ≡ 28.316846592 L | ||
≈ 61.023744 | 1 cubic inch | ≡ 0.016387064 L | ||
≈ 35.19508 | 1 imperial fluid ounce | ≡ 28.4130625 mL | ||
≈ 33.814023 | 1 US fluid ounce | ≡ 29.5735295625 mL |
See also
Rough conversions
One litre is slightly larger than a
A cubic foot has an exact volume of 28.316846592 litres.
Symbol
Originally, the only symbol for the litre was l (lowercase letter L), following the
Script l
Prior to 1979, the symbol ℓ came into common use in some countries;[citation needed] for example, it was recommended by South African Bureau of Standards publication M33 and Canada in the 1970s. This symbol can still be encountered occasionally in some English-speaking and European countries like Germany, and its use is ubiquitous in Japan and South Korea.
Fonts covering the CJK characters usually include not only the script small ℓ but also four precomposed characters: ㎕, ㎖, ㎗, and ㎘ for the microlitre, millilitre, decilitre and kilolitre to allow correct rendering for vertically written scripts. These have Unicode equivalents for compatibility, which are not recommended for use with new documents:[12]
- U+2113 ℓ SCRIPT SMALL L
- U+3395 ㎕ SQUARE MU L
- U+3396 ㎖ SQUARE ML
- U+3397 ㎗ SQUARE DL
- U+3398 ㎘ SQUARE KL
History
The first name of the litre was "cadil"; standards are shown at the
The litre was introduced in France in 1795 as one of the new "republican units of measurement" and defined as one cubic decimetre.[14] One litre of liquid water has a mass of almost exactly one kilogram, due to the gram being defined in 1795 as one cubic centimetre of water at the temperature of melting ice.[4] The original decimetre length was 44.344 lignes, which was revised in 1798 to 44.3296 lignes. This made the original litre 1.000974 of today's cubic decimetre. It was against this litre that the kilogram was constructed.
In 1879, the
In 1901, at the 3rd
In 1964, at the 12th CGPM conference, the original definition was reverted to, and thus the litre was once again defined in exact relation to the metre, as another name for the cubic decimetre, that is, exactly 1 dm3.[5]
In 1979, at the 16th CGPM conference, the alternative symbol L (uppercase letter L) was adopted. It also expressed a preference that in the future only one of these two symbols should be retained, but in 1990 said it was still too early to do so.[11]
Everyday usage
In spoken English, the symbol "mL" (for millilitre) can be pronounced as "mil". This can potentially cause confusion with some other measurement words such as:
- "mm" for millimetre, a unit of length equal to one-thousandth of a metre
- "mil" for thousandth of an inch
- "mil", a Scandinavian unit of length equal to 10 kilometres
- "mil", unit of angular measurement
The abbreviation "cc" (for
The microlitre (μL) has been known in the past as the lambda (λ), but this usage is now discouraged.[15] In the medical field the microlitre is sometimes abbreviated as mcL on test results.[16]
In the
In countries where the metric system was adopted as the official measuring system after the
For larger volumes, kilolitres, megalitres, and gigalitres, have been used by the
See also
- Acre-foot
- Claude Émile Jean-Baptiste Litre
- Integrated nanolitre system
Notes
- Bureau International des Poids et Mesures (BIPM) publication Le Système International d' Unités (SI) (BIPM, 2006). In the NIST publication, the spellings "meter", "liter" and "deka" are used rather than "metre", "litre" and "deca" as in the original BIPM English text (Taylor and Thompson, 2008a, p. iii). The Director of the NIST officially recognized this publication, together with Taylor and Thompson (2008b), as the "legal interpretation" of the SI for the United States (Turner, 2008).
References
- ^ ISBN 92-822-2213-6, archived(PDF) from the original on 4 June 2021, retrieved 16 December 2021.
- ^ Collins English Dictionary.[full citation needed]
- ^ a b Bureau International des Poids et Mesures, 2006, p. 124. ("Days" and "hours" are examples of other non-SI units that SI accepts.)
- ^ a b "Décret relatif aux poids et aux mesures du 18 germinal an 3 (7 avril 1795)" [Weights and measures decree dated 18 Germinal, Year 3 (7 April 1795)] (in French). Association Métrodiff. 7 April 1795. Archived from the original on 17 August 2016. Retrieved 8 December 2012.
Gramme, le poids absolu d'un volume d'eau pure égal au cube de la centième partie du mètre, et à la température de la glace fondante.
English translation: "Gramme: the absolute weight of a volume of pure water equal to the cube of the hundredth part of the metre, at the temperature of melting ice." - ^ a b "NIST, 2000". Ts.nist.gov. Archived from the original on 10 December 2011. Retrieved 26 April 2012.
- ^ Isotopic composition and temperature per London South Bank University's "List of physicochemical data concerning water", density and uncertainty per NIST Standard Reference Database Number 69 (Retrieved: 2010-04-05).
- ^ Kenneth Butcher, Linda Crown, Elizabeth J. Gentry (2006), The International System of Units (SI) – Conversion Factors for General Use. Archived 27 May 2010 at the Wayback Machine, NIST Special Publication 1038.
- ^ A. Thompson; B. N. Taylor (4 March 2020) [First published 2 July 2009]. "Table 6. Non-SI units accepted for use with the SI by the CIPM and this Guide". NIST. National Institute of Standards and Technology. Retrieved 30 March 2020. See footnote (b).
- ^ "The International System of Units (SI)" (PDF). 2006. p. 124. Archived from the original (PDF) on 14 August 2017. Retrieved 20 February 2021.
- NIST.
- ^ a b "Bureau International des Poids et Mesures, 2006" (PDF). Retrieved 26 April 2012.
- ^ Unicode Consortium (2019). "The Unicode Standard 12.0 – CJK Compatibility ❰ Range: 3300—33FF ❱" (PDF). Unicode.org. Retrieved 24 May 2019.
- Musée des arts et métiers. Archived from the original(PDF) on 9 November 2013. Retrieved 5 August 2013.
Comment s'est appelé cet étalon de mesure avant de s'appeler le litre ? - Le Cadil [What was the name of this measurement before called being called a litre? - a Cadil].
- ^ "Décret relatif aux poids et aux mesures du 18 germinal an 3 (7 avril 1795)" [Weights and measures decree dated 18 Germinal, Year 3 (7 April 1795)] (in French). Association Métrodiff. 7 April 1795. Archived from the original on 17 August 2016. Retrieved 8 December 2012.
Litre, la mesure de capacité, tant pour les liquides que pour les matières sèches, dont la contenance sera celle du cube de la dixièrne partie du mètre.
English translation: "Litre: unit of capacity for both liquids and solids which will be equivalent to a cube of [with sides] one tenth of a metre." - ISBN 9780323292061.
- ^ "Units of Measurement". Mayo Medical Laboratories. Retrieved 23 June 2017.
- ^ "Blood Lead Levels Chart". Retrieved 21 November 2021.
- ^ "Diabetes Blood Sugar Level Chart" (PDF). Retrieved 21 November 2021.
- ^ Water volumes - how much water?, Northern Territory Government
Bibliography
- Bureau International des Poids et Mesures (2006). "The International System of Units (SI)" (PDF). Retrieved 18 August 2008.
- Bureau International des Poids et Mesures. (2006). "The International System of Units (SI)" (on-line browser):
- Table 6 (Non-SI units accepted for use with the International System). Retrieved 2008-08-24
- National Institute of Standards and Technology (11 November 2000). "Appendix C: General tables of units of measurement". NIST Handbook 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices. National Institute of Standards and Technology. Archived from the original on 10 December 2011. Retrieved 9 October 2006.
- National Institute of Standards and Technology. (December 2003). The NIST Reference on Constants, Units, and Uncertainty: International System of Units (SI) (web site):
- Note on SI units. Retrieved 2008-08-24.
- Recommending uppercase letter L. Retrieved 2008-08-24.
- Taylor, B.N. and Thompson, A. (Eds.). (2008a). The International System of Units (SI) Archived 3 June 2016 at the Wayback Machine. United States version of the English text of the eighth edition (2006) of the International Bureau of Weights and Measures publication Le Système International d' Unités (SI) (Special Publication 330). Gaithersburg, MD: National Institute of Standards and Technology. Retrieved 2008-08-18.
- Taylor, B.N. and Thompson, A. (2008b). Guide for the Use of the International System of Units (Special Publication 811). Gaithersburg, MD: National Institute of Standards and Technology. Retrieved 2008-08-23.
- Turner, J. (Deputy Director of the National Institute of Standards and Technology). (16 May 2008)."Interpretation of the International System of Units (the Metric System of Measurement) for the United States". Federal Register Vol. 73, No. 96, p. 28432-3.
- UK National Physical Laboratory. Non-SI Units