The litre or liter is an SI accepted metric system unit of volume equal to 1 cubic decimetre,1,000 cubic centimetres or 1/1,000 cubic metre. A cubic decimetre occupies a volume of 10×10×10 centimetres and is equal to one-thousandth of a cubic metre. The original French metric system used the litre as a base unit. The word litre is derived from an older French unit, the litron, whose name came from Greek — where it was a unit of weight, not volume — via Latin, and which equalled approximately 0.831 litres. The litre was used in subsequent versions of the metric system and is accepted for use with the SI. The spelling used by the International Bureau of Weights and Measures is litre, the less common spelling of liter is more predominantly used in American English. One litre of water has a mass of almost exactly one kilogram. Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact, a litre is defined as a special name for a cubic decimetre or 10 centimetres ×10 centimetres ×10 centimetres.
Hence 1 L ≡0.001 m3 ≡1000 cm3, from 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density and standard pressure. The kilogram was in turn specified as the mass of a platinum/iridium cylinder held at Sèvres in France and was intended to be of the mass as the 1 litre of water referred to above. It was subsequently discovered that the cylinder was around 28 parts per million too large and thus, during this time, the mass-volume relationship of water depends on temperature, pressure and isotopic uniformity. In 1964, the definition relating the litre to mass was abandoned in favour of the current one, although the litre is not an official SI unit, it is accepted by the CGPM for use with the SI. CGPM defines the litre and its acceptable symbols, a litre is equal in volume to the millistere, an obsolete non-SI metric unit customarily used for dry measure. The litre is often used in some calculated measurements, such as density. One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, similarly,1 millilitre of water has a mass of about 1 g,1,000 litres of water has a mass of about 1,000 kg.
It is now known that density of water depends on the isotopic ratios of the oxygen and hydrogen atoms in a particular sample. The litre, though not an official SI unit, may be used with SI prefixes, the most commonly used derived unit is the millilitre, defined as one-thousandth of a litre, and often referred to by the SI derived unit name cubic centimetre. It is a commonly used measure, especially in medicine and cooking, Other units may be found in the table below, where the more often used terms are in bold
In science and engineering, the weight of an object is usually taken to be the force on the object due to gravity. Weight is a vector whose magnitude, often denoted by an italic letter W, is the product of the m of the object. The unit of measurement for weight is that of force, which in the International System of Units is the newton. For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, in this sense of weight, a body can be weightless only if it is far away from any other mass. Although weight and mass are scientifically distinct quantities, the terms are often confused with other in everyday use. There is a tradition within Newtonian physics and engineering which sees weight as that which is measured when one uses scales. There the weight is a measure of the magnitude of the force exerted on a body. Typically, in measuring an objects weight, the object is placed on scales at rest with respect to the earth, thus, in a state of free fall, the weight would be zero.
In this second sense of weight, terrestrial objects can be weightless, ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, is weightless. Further complications in elucidating the various concepts of weight have to do with the theory of relativity according to gravity is modelled as a consequence of the curvature of spacetime. In the teaching community, a debate has existed for over half a century on how to define weight for their students. The current situation is that a set of concepts co-exist. Discussion of the concepts of heaviness and lightness date back to the ancient Greek philosophers and these were typically viewed as inherent properties of objects. Plato described weight as the tendency of objects to seek their kin. To Aristotle weight and levity represented the tendency to restore the order of the basic elements, earth, fire. He ascribed absolute weight to earth and absolute levity to fire, archimedes saw weight as a quality opposed to buoyancy, with the conflict between the two determining if an object sinks or floats.
The first operational definition of weight was given by Euclid, who defined weight as, weight is the heaviness or lightness of one thing, compared to another, operational balances had, been around much longer. According to Aristotle, weight was the cause of the falling motion of an object
The pint /ˈpaɪnt/ is a unit of volume or capacity in both the imperial and United States customary measurement systems. In both of those systems it is traditionally one-eighth of a gallon, Imperial or U. S. although measuring a different amount of liquid, the British pint is thus about 20% larger than the American pint. Almost all other countries have standardized on the metric system, the size of what may be called a pint varies depending on local custom. The imperial pint is used in the United Kingdom and Ireland, in the United States, two pints are used, a liquid pint and a less-common dry pint. Each of these pints is one-eighth of its respective gallon, but the gallons differ, the imperial pint consists of 20 imperial fluid ounces and the US liquid pint is 16 US fluid ounces, making the imperial fluid ounce about 4% smaller than the US fluid ounce. In the United Kingdom, the pint is still the primary unit for draught beer and cider. Historically, units called a pint were used much of Europe.
Within continental Europe, the pint was replaced with the system during the 19th century. The imperial pint is equal to one-eighth of an imperial gallon, the United States liquid pint is equal to one-eighth of a United States liquid gallon. It is used commonly in the United States, the United States dry pint is equal to one-eighth of a United States dry gallon. It is used in the United States, but is not as common as the liquid pint, a now-obsolete unit of measurement in Scotland known as the Scottish pint or joug equals three imperial pints. It remained in use until the 19th century, surviving significantly longer than most of the old Scottish measurements, the French word pinte is etymologically related, but historically described a larger unit. The Royal pint was 48 French cubic inches and this is one of numerous false friends which exist between English and French. They are not the same although they have the same linguistic origin - the French Canadian pinte is actually equivalent to the English quart.
If you want to order an English pint of beer in Canadian French, the Imperial system of measurement is no longer taught in Canadian schools, so servers may be unclear on how big a pint or pinte is regardless of language. In Flanders, the word pintje, meaning little pint, refers only to a 250 mL glass of lager, some West- and East-Flemish dialects use it as a word for beaker. The equivalent word in German, refers to a glass of a third of a litre in Cologne, one US fluid pint of water weighs about a pound, resulting in the popular saying, The pints a pound, the world around. A different saying for the pint is a pint of pure water weighs a pound
The gill or teacup is a unit of measurement for volume equal to a quarter of a pint. It is no longer in use, except in regard to the volume of alcoholic spirits measures. The 1⁄4 gill was previously the most common measure in Scotland, in southern England, it is called a noggin. In northern England, the large noggin is used, in some areas, a gill came to mean half a pint for both beer and milk. In Ireland, the standard spirit measure was historically 1⁄4 gill, in the Republic of Ireland, it still retains this value, though it is now legally specified in metric units as 35.5 ml. In the popular song The Crystal Ship recorded by The Doors, in L. Frank Baums The Patchwork Girl of Oz one of the ingredients required for a magic spell is a gill of water from a dark well. In chapter 19 the obscure unit is used for including a pun with Jack and Jill. In Bart the Genius, an episode of The Simpsons, a child tricks Bart by offering, a gill is referenced in season 2 episode 3 Blood Test Archer when Barry explains to Archer that a liter is, about 8 gills.
In George Orwells Animal Farm, Moses the Raven is allotted a gill of beer a day after he returns, with the implication that this is part of his payment for supporting the farm leaders, the pigs. Because of its widely used homograph, gill is often mispronounced with a hard g sound. FXs animated cartoon Archer, mispronounced gill in both Episodes Blood Test and Heart of Archness, Part Three, show host Stephen Fry mispronounced gill in a 2013 edition of the BBC TV programme QI
United States customary units
United States customary units are a system of measurements commonly used in the United States. The United States customary system developed from English units which were in use in the British Empire before the US declared its independence, the British system of measures was overhauled in 1824 to create the imperial system, changing the definitions of some units. Therefore, while many U. S. units are similar to their Imperial counterparts. The majority of U. S. customary units were redefined in terms of the meter and these definitions were refined by the international yard and pound agreement of 1959. Americans primarily use customary units in commercial activities, as well as for personal and social use, in science, many sectors of industry and some of government, metric units are used. The International System of Units, the form of the metric system, is preferred for many uses by the U. S. National Institute of Standards. The United States system of units is similar to the British imperial system, both systems are derived from English units, a system which had evolved over the millennia before American independence, and which had its roots in Roman and Anglo-Saxon units.
The customary system was championed by the U. S. -based International Institute for Preserving and Perfecting Weights, advocates of the customary system saw the French Revolutionary, or metric, system as atheistic. An auxiliary of the Institute in Ohio published a poem with wording such as down with every metric scheme and A perfect inch, one adherent of the customary system called it a just weight and a just measure, which alone are acceptable to the Lord. The U. S. government passed the Metric Conversion Act of 1975, the legislation states that the federal government has a responsibility to assist industry as it voluntarily converts to the metric system, i. e. metrification. This is most evident in U. S. labeling requirements on food products, according to the CIA Factbook, the United States is one of three nations that have not adopted the metric system as their official system of weights and measures. U. S. customary units are used on consumer products. Metric units are standard in science, medicine, as well as many sectors of industry and government, the metric system lacks a parallel to the foot.
Frequently, these units designate quite different sizes, for example, the mile ranged by country from one-half to five U. S. miles and pound had varying definitions. Historically, a range of non-SI units were used in the U. S. and in Britain. This article deals only with the commonly used or officially defined in the U. S. For measuring length, the U. S. customary system uses the inch, foot and mile, since July 1,1959, these have been defined on the basis of 1 yard =0.9144 meters except for some applications in surveying. The U. S. the United Kingdom and other Commonwealth countries agreed on this definition, the NAD27 was replaced in the 1980s by the North American Datum of 1983, which is defined in meters
The gallon is a unit of measurement for liquid capacity in both the US customary units and the British imperial systems of measurement. Three significantly different sizes are in current use, the imperial gallon defined as 4, while there is no official symbol for the gallon, gal is in common use. The gallon currently has one definition in the system. Historically, there were many definitions and redefinitions, there were more than a few systems of liquid measurements in the pre-1884 United Kingdom. The imperial fluid ounce is defined as 1⁄160 of a gallon, there are four quarts in a gallon. The US gallon is legally defined as 231 cubic inches, which is exactly 3.785411784 liters, a US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 °F, making it about 16. 6% lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes the US fluid ounce equal to 1⁄128 of a US gallon. For example, the volume of products and alcoholic beverages are both referenced to 60 °F in government regulations.
This dry measure is one-eighth of a US Winchester bushel of 2150.42 cubic inches, the US dry gallon is not used in commerce, and is not listed in the relevant statute, which jumps from the dry quart to the peck. The Imperial gallon is used in life in the United Kingdom. Gallons used in fuel economy expression in Canada are Imperial gallons, the gallon was removed from the list of legally defined primary units of measure catalogued in the EU directive 80/181/EEC, for trading and official purposes, with effect from 31 December 1994. Under the directive the gallon could still be used – but only as a supplementary or secondary unit, Ireland passed legislation in response to the EU directive with the effective date being 31 December 1993. Though the gallon has ceased to be the legally defined primary unit, it can still be used in both the UK and Ireland as a supplementary unit. The Imperial gallon continues to be used as a unit of measure in Anguilla and Barbuda, the Bahamas, the British Virgin Islands, the Cayman Is.
Dominica, Montserrat, Myanmar, St. Kitts & Nevis, St. Lucia, and St. Vincent & the Grenadines. Other than the United States, the US gallon is used in Liberia, Colombia, The Dominican Republic, Ecuador, El Salvador, Haiti, Honduras and Peru. The United Arab Emirates started selling gasoline by the litre in 2010, along with Guyana, the two former had used the Imperial gallon, and the latter the US gallon until they switched. Antigua and Barbuda plan to switch over to using litres by 2015
Fahrenheit is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit, after whom the scale is named. It uses the degree Fahrenheit as the unit, several accounts of how he originally defined his scale exist. The lower defining point,0 °F, was established as the temperature of a solution of brine made from parts of ice. Further limits were established as the point of ice and his best estimate of the average human body temperature. All other countries in the world now use the Celsius scale, defined since 1954 by absolute zero being −273.15 °C, on the Fahrenheit scale, the freezing point of water is 32 degrees Fahrenheit and the boiling point is 212 °F. This puts the boiling and freezing points of water exactly 180 degrees apart, therefore, a degree on the Fahrenheit scale is 1⁄180 of the interval between the freezing point and the boiling point. On the Celsius scale, the freezing and boiling points of water are 100 degrees apart, a temperature interval of 1 °F is equal to an interval of 5⁄9 degrees Celsius.
The Fahrenheit and Celsius scales intersect at −40°, absolute zero is −273.15 °C or −459.67 °F. For an exact conversion, the formulas can be applied. Again, f is the value in Fahrenheit and c the value in Celsius, f °Fahrenheit to c °Celsius, C °Celsius to f °Fahrenheit, −40 = f. Fahrenheit proposed his temperature scale in 1724, basing it on two points of temperature. In his initial scale, the point is determined by placing the thermometer in a mixture of ice, water. This is a mixture which stabilizes its temperature automatically, that stable temperature was defined as 0 °F. The second point,96 degrees, was approximately the human bodys temperature, in any case, the definition of the Fahrenheit scale has changed since. According to a letter Fahrenheit wrote to his friend Herman Boerhaave, his scale was built on the work of Ole Rømer, whom he had met earlier. In Rømers scale, brine freezes at zero, water freezes and melts at 7.5 degrees, body temperature is 22.5, Fahrenheit multiplied each value by four in order to eliminate fractions and increase the granularity of the scale.
Fahrenheit observed that water boils at about 212 degrees using this scale, under this system, the Fahrenheit scale is redefined slightly so that the freezing point of water is exactly 32 °F, and the boiling point is exactly 212 °F or 180 degrees higher. It is for this reason that human body temperature is approximately 98° on the revised scale
In physics, mass is a property of a physical body. It is the measure of a resistance to acceleration when a net force is applied. It determines the strength of its gravitational attraction to other bodies. The basic SI unit of mass is the kilogram, Mass is not the same as weight, even though mass is often determined by measuring the objects weight using a spring scale, rather than comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity and this is because weight is a force, while mass is the property that determines the strength of this force. In Newtonian physics, mass can be generalized as the amount of matter in an object, however, at very high speeds, special relativity postulates that energy is an additional source of mass. Thus, any body having mass has an equivalent amount of energy. In addition, matter is a defined term in science. There are several distinct phenomena which can be used to measure mass, active gravitational mass measures the gravitational force exerted by an object.
Passive gravitational mass measures the force exerted on an object in a known gravitational field. The mass of an object determines its acceleration in the presence of an applied force, according to Newtons second law of motion, if a body of fixed mass m is subjected to a single force F, its acceleration a is given by F/m. A bodys mass determines the degree to which it generates or is affected by a gravitational field and this is sometimes referred to as gravitational mass. The standard International System of Units unit of mass is the kilogram, the kilogram is 1000 grams, first defined in 1795 as one cubic decimeter of water at the melting point of ice. Then in 1889, the kilogram was redefined as the mass of the prototype kilogram. As of January 2013, there are proposals for redefining the kilogram yet again. In this context, the mass has units of eV/c2, the electronvolt and its multiples, such as the MeV, are commonly used in particle physics. The atomic mass unit is 1/12 of the mass of a carbon-12 atom, the atomic mass unit is convenient for expressing the masses of atoms and molecules.
Outside the SI system, other units of mass include, the slug is an Imperial unit of mass, the pound is a unit of both mass and force, used mainly in the United States
The pound or pound-mass is a unit of mass used in the imperial, United States customary and other systems of measurement. The international standard symbol for the pound is lb. The unit is descended from the Roman libra, the English word pound is cognate with, among others, German Pfund, Dutch pond, and Swedish pund. All ultimately derive from a borrowing into Proto-Germanic of the Latin expression lībra pondō, usage of the unqualified term pound reflects the historical conflation of mass and weight. This accounts for the modern distinguishing terms pound-mass and pound-force, the United States and countries of the Commonwealth of Nations agreed upon common definitions for the pound and the yard. Since 1 July 1959, the avoirdupois pound has been defined as exactly 0.45359237 kg. In the United Kingdom, the use of the pound was implemented in the Weights and Measures Act 1963.9144 metre exactly. An avoirdupois pound is equal to 16 avoirdupois ounces and to exactly 7,000 grains, the conversion factor between the kilogram and the international pound was therefore chosen to be divisible by 7, and an grain is thus equal to exactly 64.79891 milligrams.
The US has not adopted the system despite many efforts to do so. Historically, in different parts of the world, at different points in time, and for different applications, the libra is an ancient Roman unit of mass that was equivalent to approximately 328.9 grams. It was divided into 12 unciae, or ounces, the libra is the origin of the abbreviation for pound, lb. A number of different definitions of the pound have historically used in Britain. Amongst these were the avoirdupois pound and the tower, merchants. Historically, the sterling was a tower pound of silver. In 1528, the standard was changed to the Troy pound, the avoirdupois pound, known as the wool pound, first came into general use c. It was initially equal to 6992 troy grains, the pound avoirdupois was divided into 16 ounces. During the reign of Queen Elizabeth, the pound was redefined as 7,000 troy grains. Since then, the grain has often been a part of the avoirdupois system
The system of imperial units or the imperial system is the system of units first defined in the British Weights and Measures Act of 1824, which was refined and reduced. The Imperial units replaced the Winchester Standards, which were in effect from 1588 to 1825, the system came into official use across the British Empire. The imperial system developed from what were first known as English units, the Weights and Measures Act of 1824 was initially scheduled to go into effect on 1 May 1825. However, the Weights and Measures Act of 1825 pushed back the date to 1 January 1826, the 1824 Act allowed the continued use of pre-imperial units provided that they were customary, widely known, and clearly marked with imperial equivalents. Apothecaries units are mentioned neither in the act of 1824 nor 1825, at the time, apothecaries weights and measures were regulated in England and Berwick-upon-Tweed by the London College of Physicians, and in Ireland by the Dublin College of Physicians. In Scotland, apothecaries units were unofficially regulated by the Edinburgh College of Physicians, the three colleges published, at infrequent intervals, the London and Dublin editions having the force of law.
The Medical Act of 1858 transferred to The Crown the right to publish the official pharmacopoeia and to regulate apothecaries weights, Metric equivalents in this article usually assume the latest official definition. Before this date, the most precise measurement of the imperial Standard Yard was 0.914398416 metres, in 1824, the various different gallons in use in the British Empire were replaced by the imperial gallon, a unit close in volume to the ale gallon. It was originally defined as the volume of 10 pounds of distilled water weighed in air with brass weights with the standing at 30 inches of mercury at a temperature of 62 °F. The Weights and Measures Act of 1985 switched to a gallon of exactly 4.54609 l and these measurements were in use from 1826, when the new imperial gallon was defined, but were officially abolished in the United Kingdom on 1 January 1971. In the USA, though no longer recommended, the system is still used occasionally in medicine. The troy pound was made the unit of mass by the 1824 Act, its use was abolished in the UK on 1 January 1879, with only the troy ounce.
The Weights and Measures Act 1855 made the pound the primary unit of mass. In all the systems, the unit is the pound. For the yard, the length of a pendulum beating seconds at the latitude of Greenwich at Mean Sea Level in vacuo was defined as 39.01393 inches, the imperial system is one of many systems of English units. Although most of the units are defined in more than one system, some units were used to a much greater extent, or for different purposes. The distinctions between these systems are not drawn precisely. One such distinction is that between these systems and older British/English units/systems or newer additions, the US customary system is historically derived from the English units that were in use at the time of settlement
The cup is a unit of measurement for volume, used in cooking to measure liquids and bulk foods such as granulated sugar. Using millilitre/decilitre measures is an option to avoid ambiguity. Some countries in the Commonwealth of Nations, notably Australia and New Zealand and it is used in the US to specify coffeemaker sizes. A 12-cup US coffeemaker makes 57.6 US customary fluid ounces of coffee, in older recipes cup may mean coffee cup. United States customary cup is defined as half a U. S. pint, a customary cup of coffee in the U. S. is usually defined as 4 fluid ounces, brewed using 5 fluid ounces of water. Coffee carafes used with drip coffee makers, such as Black, the cup currently used in the United States for nutrition labelling is defined in United States law as 240 ml. The imperial cup is half an imperial pint and it is no longer in common use, but many recipe books still include it. The Japanese cup is defined as 200 ml. The traditional Japanese cup, the gō, is approximately 180 ml.10 gō make one shō, gō cups are typically used for measuring rice, and sake is typically sold by the cup, the bottle, and flask sizes.
Note modern sake bottle sizes are almost the same as the 750 ml international standard for wine bottles, in European cuisine the cup measure may be found in older recipes, with sometimes uncertain meaning, the transition to the metric system was generally made in the 19th century. In Latin American recipes a cup may be interpreted as 200 ml,250 ml or as a US cup measure, depending on country, in parallel the measure glass may be 200 ml. In Europe, cooking recipes normally state any liquid volume larger than a few tablespoons in millilitres, most recipes in Europe use the millilitre or decilitre as a measure of volume. For example, where an American customary recipe might specify 1 cup of sugar and 2 cups of milk, conversion between the two measures must take into account the density of the ingredients, and some recipes specify both weight and volume to simplify. Many European measuring cups have additional weight scales besides the dl or ml scale for common ingredients like sugar, flour