There are two international standard symbols for the litre: L and l. However, some authorities advise against some of them for example, in the United States, NIST advocates using the millilitre or litre instead of the centilitre. Other units may be found in the table below, where the more often used terms are in bold. It is a commonly used measure, especially in medicine, cooking and automotive engineering. The most commonly used derived unit is the millilitre, defined as one-thousandth of a litre, and also often referred to by the SI derived unit name "cubic centimetre". The litre, though not an official SI unit, may be used with SI prefixes. 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 0.999 975 ☐.000 001 kg/L at its point of maximum density (3.984 ☌) under one standard atmosphere (101.325 kPa) of 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. 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 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). One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at about 4 ☌. The litre is often also used in some calculated measurements, such as density (kg/L), allowing an easy comparison with the density of water. 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. CGPM defines the litre and its acceptable symbols.Ī litre is equal in volume to the millistere, an obsolete non-SI metric unit formerly customarily used for dry measure. Although the litre is not an SI unit, it is accepted by the CGPM (the standards body that defines the SI) for use with the SI. In 1964, the definition relating the litre to mass was superseded by the current one. Additionally, the mass–volume relationship of water (as with any fluid) depends on temperature, pressure, purity and isotopic uniformity. It was subsequently discovered that the cylinder was around 28 parts per million too large and thus, during this time, a litre was about 1.000 028 dm 3. The kilogram was in turn specified as the mass of the International Prototype of the Kilogram (a specific platinum/iridium cylinder) and was intended to be of the same mass as the 1 litre of water referred to above. a cubic metre, which is the SI unit for volume) is exactly 1000 L.įrom 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density (+3.98 ☌) and standard pressure. Definition Some SI units of volume to scale and approximate corresponding mass of waterĪ litre is a cubic decimetre, which is the volume of a cube 10 centimetres × 10 centimetres × 10 centimetres (1 L ≡ 1 dm 3 ≡ 1000 cm 3). Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact. 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 ☌). The spelling "liter" is predominantly used in American English. The spelling used by the International Bureau of Weights and Measures is "litre", a spelling which is shared by most English-speaking countries. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI, although not an SI unit-the SI unit of volume is the cubic metre (m 3). The word litre is derived from an older French unit, the litron, whose name came from Byzantine Greek-where it was a unit of weight, not volume -via Late Medieval Latin, and which equalled approximately 0.831 litres. The original French metric system used the litre as a base unit. A cubic decimetre (or litre) occupies a volume of 10 cm × 10 cm × 10 cm (see figure) and is thus equal to one-thousandth of a cubic metre. It is equal to 1 cubic decimetre (dm 3), 1000 cubic centimetres (cm 3) or 0.001 cubic metres (m 3). The litre ( Commonwealth English spelling) or liter ( American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. One-litre beer mugs ( German: Maßkrüge) at the 2006 Oktoberfest in Germany One litre is equal to the volume of a cubic decimetre.
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