The metric system is an internationally recognised decimalised system of measurement. It is in widespread use, where it is adopted, it is the only or most common system of weights and measures, it is now known as the International System of Units. It is used to measure everyday things such as the mass of a sack of flour, the height of a person, the speed of a car, the volume of fuel in its tank, it is used in science and trade. In its modern form, it consists of a set of base units including metre for length, kilogram for mass, second for time and ampere for electrical current, a few others, which together with their derived units, can measure any physical quantity. Metric system may refer to other systems of related base and derived units defined before the middle of the 20th century, some of which are still in limited use today; the metric system was designed to have properties that make it easy to use and applicable, including units based on the natural world, decimal ratios, prefixes for multiples and sub-multiples, a structure of base and derived units.
It is a coherent system, which means that its units do not introduce conversion factors not present in equations relating quantities. It has a property called rationalisation that eliminates certain constants of proportionality in equations of physics; the units of the metric system taken from observable features of nature, are now defined by phenomena such as the microwave frequency of a caesium atomic clock which measures seconds. One unit, the kilogram, remains defined in terms of a man-made artefact, but scientists voted to change the definition to one based on Planck's constant via a Kibble balance; the new definition is expected to be formally propagated on 20 May 2019. While there are numerous named derived units of the metric system, such as watt and lumen, other common quantities such as velocity and acceleration do not have their own unit, but are defined in terms of existing base and derived units such as metres per second for velocity. Though other or widespread systems of weights and measures continue to exist, such as the British imperial system and the US customary system of weights and measures, in those systems most or all of the units are now defined in terms of the metric system, such as the US foot, now a defined decimal fraction of a metre.
The metric system is extensible, new base and derived units are defined as needed in fields such as radiology and chemistry. The most recent derived unit, the katal, for catalytic activity, was added in 1999. Recent changes are directed toward defining base units in terms of invariant constants of physics to provide more precise realisations of units for advances in science and industry; the modern metric system consists of four electromechanical base units representing seven fundamental dimensions of measure: length, time, thermodynamic temperature, luminous intensity, quantity of substance. The units are: the metre for length kilogram for mass second for time ampere for electromagnetism kelvin for temperature candela for luminous intensity mole for quantityTogether they are sufficient for measuring any known quantity, without reference to further quantities or phenomena; the metre, ampere and mole are all defined in terms of other base units. For example, the speed of light is defined as 299,792,458 metres per second, the metre is derived from that constant and the definition of a second.
As a result, in dimensional analysis, they remain wholly separate concepts. There are 22 derived units with special names in the metric system, these are defined in terms of the base units or other named derived units. Eight of these units are electromagnetic quantities: volt, a unit of electrical potential ohm, a unit of electrical resistance tesla, a unit of magnetic flux density weber, a unit of magnetic flux farad, a unit of electrical capacitance henry, a unit of electrical inductance siemens, a unit of electrical conductance coulomb, a unit of electrical chargeFour of these units are mechanical quantities: watt, a unit of mechanical or electrical power newton, a unit of mechanical force joule, a unit of mechanical, electrical or thermodynamic energy pascal, a unit of pressureFive units represent measures of electromagnetic radiation and radioactivity: becquerel, a unit of radioactive decay sievert, a unit of absorbed ionising radiation gray, a unit of ionising radiation lux, a unit of luminous flux lumen, a unit of luminous intensityTwo units are measures of circular arcs and spherical surfaces: radian, a unit of circular arc steradian, a unit of spherical surface areaThree units are miscellaneous: degree Celsius, a unit of thermodynamic temperature katal, a unit of catalytic activity hertz, a unit of cycles per second Although SI, as published by the CGPM, should, in theory, meet all the requirements of commerce and technology, certain customary units of measure have acquired established positions within the world community.
In order that such units are used around the world, the CGPM catalogued such units in Tables 6 to 9 of the SI brochure. These categories are: Non-SI units accepted for use with the International System of Units; this list includes the hour and minute, the angular measures, the historic metric units, the litre and hectare Non-SI units whose values in SI units must be obtained experimentally. This list includes various units of measure used in atomic and nuclear physics and in astronomy such as the dalton, the electron mass, the electron volt, the astronomical unit
The gram is a metric system unit of mass. Defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre, at the temperature of melting ice". 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 now defined by the International Bureau of Weights and Measures, not in terms of grams, but by "the amount of electricity needed to counteract its force" The only unit symbol for gram, recognised by the International System of Units 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", "gm" or "Gm". 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 of a cubic centimetre of water. French gramme was taken from the Late Latin term gramma.
This word—ultimately from Greek γράμμα, "letter"—had adopted a specialised meaning in Late Antiquity of "one twenty-fourth part of an ounce", corresponding to about 1.14 modern grams. This use of the term is found in the carmen de ponderibus et mensuris composed around 400 AD. There is evidence that the Greek γράμμα was used in the same sense at around the same time, in the 4th century, survived in this sense into Medieval Greek, while the Latin term did not remain current in Medieval Latin and was recovered in Renaissance scholarship; the gram was the fundamental unit of mass in the 19th-century centimetre–gram–second system of units. 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 used unit of measurement for non-liquid ingredients in cooking and grocery shopping worldwide.
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 be read as a percentage by weight. 1 gram = 15.4323583529 grains 1 grain = 0.06479891 grams 1 avoirdupois ounce = 28.349523125 grams 1 troy ounce = 31.1034768 grams 100 grams = 3.527396195 ounces 1 gram = 5 carats 1 gram = 8.98755179×1013 joules 1 undecimogramme = 1 "eleventh-gram" = 10−11 grams in the historic quadrant–eleventh-gram–second system a.k.a. hebdometre–undecimogramme–second system 500 grams = 1 Jin in the Chinese units of measurement. 1 gram is equal to 1 small paper clip or pen cap. The Japanese 1 yen coin has a mass of one gram, lighter than the British penny, the United States cent, the Euro cent, the 5 cent Australian coins. Conversion of units Duella Gold gram Orders of magnitude Gram at Encyclopædia Britannica
A measuring cup or measuring jug is a kitchen utensil used to measure the volume of liquid or bulk solid cooking ingredients such as flour and sugar for volumes from about 50 mL upwards. Measuring cups are used to measure washing powder, liquid detergents and bleach for clothes washing; the cup will have a scale marked in cups and fractions of a cup, with fluid measure and weight of a selection of dry foodstuffs. Measuring cups may be made of glass, or metal. Transparent cups can be read from an external scale. Measuring cups have capacities from 250 mL to 1000 mL, though larger sizes are available for commercial use, they have scale markings at different heights: the substance being measured is added to the cup until it reaches the wanted level. Dry measure cups without a scale are sometimes used, in sets of 1/4, 1/3, 1/2, 1 cup; the units may be milliliters or fractions of a liter, or the cup with its fractions and fluid ounces. Dry measure cups are distinguished from liquid measure cups in that they are meant to be filled to the top so that excess may be scraped off and shallow for easy cleaning.
Liquid measure cups tend to be microwave safe for heating and clear to more judge the meniscus. Sometimes multiples of teaspoons and tablespoons are included. There may be scales for the approximate weight for particular substances, such as flour and sugar. Many dry ingredients, such as granulated sugar, are not compressible, so volume measures are consistent. Others, notably flour, are more variable. For example, 1 cup of all-purpose flour sifted into a cup and leveled weighs about 100 grams, whereas 1 cup of all-purpose flour scooped from its container and leveled weighs about 140 grams. Using a measuring cup to measure bulk foods which can be compressed to a variable degree such as chopped vegetables or shredded cheese leads to large measurement uncertainties, it is easier to chop down the units for a better measure. Cup Kitchen scale Spoon scale WBUR story on a measuring cup design which keep a perfect ratio of surface area to volume, for consistent accuracy
A dessert spoon is a spoon designed for eating dessert and sometimes used for soup or cereals. Similar in size to a soup spoon but with an oval rather than round bowl, it has a capacity around twice that of a teaspoon. By extension the term'dessert spoon' is used as a cooking measure of volume of 10ml of 0.4 fl oz. The use of dessert spoons around the world varies greatly. In most traditional table settings, the dessert spoon is placed above the plate or bowl, separated from the rest of the cutlery, or it may be brought in with the dessert; as a unit of culinary measure, a level dessertspoon equals 2 teaspoons. In the United States this is 0.4 of a fluid ounce. In the UK it is 10 ml; as a unit of Apothecary measure, the dessert-spoon was an unofficial but used unit of fluid measure equal to two fluid drams, or 1⁄4 fluid ounce. In the United States and pre-1824 England, the fluid ounce was 1⁄128 of a Queen Anne wine gallon thus making the dessert-spoon 7.39 ml. The post-1824 imperial Apothecaries' dessert-spoon was 1⁄4 fluid ounce, but the ounce in question was 1⁄160 of an imperial gallon, defined as 277.274 cubic inches, but adjusted to 277.419433 cubic inches, in either case yielding a dessert-spoon of 7.10 ml.
In both the British and American variants of the Apothecaries' system, two tea-spoons make a dessert-spoon, while two dessert-spoons make a table-spoon. In pharmaceutical Latin, the Apothecaries' dessert-spoon is known as cochleare medium, abbreviated as cochl. Med. or less coch. med. as opposed to the tea-spoon and table-spoon. Cooking weights and measures Teaspoon Tablespoon Silver place settings, from Butler's Guild
The ge is a traditional Chinese unit of volume equal to 1/10 sheng. Its Korean equivalent is the hob or hop and its Japanese equivalent is the gō; the ge is a traditional Chinese unit of volume equal to 1⁄10 sheng. Its exact value has varied over time with the size of the sheng. In 1915, the Beiyang Government set the ge as equivalent to 103.54688 milliliters. The Nationalist Government's 1929 Weights and Measures Act, effective 1 January 1930, set it equal to the deciliter; the People's Republic of China confirmed that value in 1959, although it made the official Chinese name of the deciliter the fēnshēng and exempted TCM pharmacists from punishment for noncompliance with the new measure when traditional amounts were required for preparing medicine. The hob or hop is a traditional Korean unit based on the ge, equal to 1⁄10 doe or toe, its exact value has varied over time with the size of the doe. During its occupation, Korea's native measures were standardized to their Japanese equivalents; the present-day hob is 2401/13310 litres, the same as the Japanese gō.
Its use for commercial purposes has been criminalized in South Korea, although it continues to be used in the North. The gō or cup is a traditional Japanese unit based on the ge, equal to 10 shaku or 1⁄10 shō, it was equated with 2401/13310 liters in 1891. The gō is the traditional amount used for a cup of sake in Japanese cuisine. Although the gō is no longer used as an official unit, 1-gō measuring cups or their 180 mL metric equivalents are included with Japanese rice cookers. In dining, a 1-gō serving is sometimes equated with 150 g of Japanese short-grain rice, it appears as a serving size for fugu and other fish. Since sake bottles are either 720 or 750 mL, they can be reckoned as holding about four cups; the gō is used as a unit equal to 1⁄10 tsubo. This is equal to 0.3306 m². In Japanese mountaineering terms, Go is a about 1/10 time rate in climbing journey, it is sometime called "station" in English. Japanese cup, a separate modern unit of 200 mL
Tasse à café
A tasse à café is a cup of white porcelain and of around 120 ml, in which coffee is served. It is sometimes used to serve small portions of rich drinks, such as hot chocolate The word originates from Arabic ṭās طاس, from the Persian ṭās طاس, meaning cup or bowl. A half-sized cup is called a demi-tasse "half-cup"
The pint 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; the British imperial pint is about 20% larger than the American pint because the two systems are defined differently. All other countries have standardized on the metric system, so 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 and to a limited extent in Commonwealth nations. In the United States, two pints are used: a less-common dry pint; each of these pints is one-eighth of its respective gallon. This difference dates back to 1824, when the British Weights and Measures Act standardised various liquid measures throughout the British Empire, while the United States continued to use the earlier English measure; 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.
All of the other former British colonies, such as Canada, South Africa and New Zealand, converted to the metric system in the 1960s and 1970s. In the United Kingdom, the imperial pint is still the primary unit for draught beer and cider, as it is for milk sold in returnable bottles and some cartons. In the UK, legislation mandates that draught beer and cider may be sold by the imperial pint in perpetuity, in public houses can only be sold in a third of a pint, two-thirds of a pint or multiples of half a pint, which must be served in stamped measured glasses or from government-stamped meters. Since the majority of countries in the world no longer use American or British imperial units, most are non-English speaking, a "pint of beer" served in a tavern outside the United Kingdom and the United States may be measured by other standards. In Commonwealth countries it may be a British imperial pint of 568 ml, in countries serving large numbers of American tourists it might be a US liquid pint of 473 ml, in many metric counties it is a half-litre of 500 ml, or in some places it is another measure reflecting national and local laws and customs.
Units called a pint were used across much of Europe, with values varying between countries from less than half a litre to over one litre. Within continental Europe, these pints were replaced with liquid measures based on the metric system during the 19th century; the term is still in limited use in parts of France, where "une pinte" means an imperial quart, 2 imperial pints, whereas a pint is "une chopine"—and Central Europe, notably some areas of Germany and Switzerland, where "ein Schoppen" is colloquially used for half a litre. In Spanish holiday resorts frequented by British tourists,'pint' is taken to mean a beer glass. Half-pint and pint mugs may therefore be referred to as pinta pinta grande. Pint comes from the Old French word pinte and ultimately from Vulgar Latin pincta meaning "painted", for marks painted on the side of a container to show capacity; the imperial pint is equal to one-eighth of an imperial gallon. In the United States, the liquid pint is defined as one-eighth of a liquid gallon of 231 cubic inches.
In the United States, the dry pint is one-eighth of a dry gallon. The United States dry pint is equal to one-eighth of a United States dry gallon, it 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 longer than most of the old Scottish measurements. This is one of numerous false friends which exist between French, they are not the same unit. The French word pinte is etymologically related, but described a larger unit; the Royal pint was 48 French cubic inches. But regional pints varied in size depending on locality and on commodity varying from 0.95 L to over 2 L. In Canada, the Weights and Measures Act, which has the laws in English and French printed side-by-side, defines a pint in English as 1/8 of a gallon, but defines a pinte in French as 1/4 of a gallon. Thus, if you speak English and order "a pint of beer", servers are required to serve you 568 ml of beer, but if you speak French and order "une pinte de bière", they are required to serve an Imperial quart, 1136 ml—twice as much.
To order an Imperial pint when speaking French in Canada, one must instead order une chopine de bière. 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 and the Rhineland. In South Australia, ordering "a pint of beer" results in 425 ml being served. Customers must request "an Imperial pint of beer" to get 570 ml. Australians from other states contest the size of their beers in Adelaide. One US fluid pint of water weighs about a pound, resulting in the popular saying, "A pint's a pound, the world around." However, a US pint of water weighs 1.04375 pounds and the statement does not hold the world around because the impe