List of unusual units of measurement explained

An unusual unit of measurement is a unit of measurement that does not form part of a coherent system of measurement, especially because its exact quantity may not be well known or because it may be an inconvenient multiple or fraction of a base unit.

Many of the unusual units of measurements listed here are colloquial measurements, units devised to compare a measurement to common and familiar objects.

Length

Centimorgan

In genetics, a centimorgan (abbreviated cM) or map unit (m.u.) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01. It is often used to infer distance along a chromosome. One centimorgan corresponds to about 1 million base pairs in humans on average.

Horizontal pitch

Horizontal pitch (HP) is a unit of length defined by the Eurocard printed circuit board standard used to measure the horizontal width of rack mounted electronic equipment, similar to the rack unit (U) used to measure vertical heights of rack mounted equipment. One HP is 0.2 inches (1/5") or NaNinches wide.

Hammer unit

Valve's Source game engine uses the Hammer unit as its base unit of length. This unit refers to Source's official map creation software, Hammer.[1] The exact definition varies from game to game, but a Hammer unit is usually defined as a sixteenth of a foot (16 Hammer units = 1 foot). This means that 1 Hammer unit is equal to exactly NaNfeet or NaNfeet (3/4").

Rack unit

See main article: Rack unit. One rack unit (U) is 1.75inches and is used to measure rack-mountable audiovisual, computing and industrial equipment. Rack units are typically denoted without a space between the number of units and the 'U'. Thus, a 4U server enclosure (case) is 7inches high, or more practically, built to occupy a vertical space seven inches high, with sufficient clearance to allow movement of adjacent hardware.

Hand

See main article: Hand (unit). The hand is a non-SI unit of length equal to exactly 4inches. It is normally used to measure the height of horses in some English-speaking countries, including Australia,[2] Canada, Ireland, the United Kingdom, and the United States. It is customary when measuring in hands to use a point to indicate inches (quarter-hands) and not tenths of a hand. For example, 15.1 hands normally means 15 hands, 1 inch (5 ft 1 in), rather than hands.[3]

Light-nanosecond

The light-nanosecond is defined as exactly 29.9792458 cm. It was popularized in information technology as a unit of distance by Grace Hopper as the distance which a photon could travel in one billionth of a second (roughly 30 cm or one foot): "The speed of light is one foot per nanosecond."[4] [5]

Metric feet

A metric foot, defined as 300mm), has been used occasionally in the UK but has never been an official unit.[6]

A Chinese foot is around one third of a metre, with the exact definition depending on jurisdiction.

Horse

See main article: Horse length. Horses are used to measure distances in horse racing – a horse length (shortened to merely a length when the context makes it obvious) equals roughly 8feet. Shorter distances are measured in fractions of a horse length; also common are measurements of a full or fraction of a head, a neck, or a nose.[7]

Boat length

In rowing races such as the Oxford and Cambridge Boat Race, the margin of victory and of defeat is expressed in fractions and multiples of boat lengths. The length of a rowing eight is about 62feet. A shorter distance is the canvas, which is the length of the covered part of the boat between the bow and the bow oarsman. The Racing Rules of Sailing also makes heavy use of boat lengths.

Football field (length)

A football field is often used as a comparative measurement of length when talking about distances that may be hard to comprehend when stated in terms of standard units.

An American football field is usually understood to be 100yd long, though it is technically 120yd when including the two 10adj=onNaNadj=on long end zones. The field is 160feet wide.[8]

An association football pitch may vary within limits of 90- in length and 45- in width. The recommended field size is 105x for major competitions such as the FIFA World Cup, UEFA European Championship and UEFA Champions League.

A Canadian football field is 65yd wide and 150yd long, including two 20adj=onNaNadj=on long end zones.

Block

In most US cities, a city block is between NaNand. In Manhattan, the measurement "block" usually refers to a north–south block, which is NaNmiles. Sometimes people living in places (like Manhattan) with a regularly spaced street grid will speak of long blocks and short blocks. Within a typical large North American city, it is often only possible to travel along east–west and north–south streets, so travel distance between two points is often given in the number of blocks east–west plus the number north–south (known to mathematicians as the Manhattan Metric).[9]

Earth radius

The globally-average radius of Earth, generally given as 6,371 kilometres (3,959 miles), is often employed as a unit of measure to intuitively compare objects of planetary size.

Lunar distance

Lunar distance (LD), the distance from the centre of Earth to the centre of the Moon, is a unit of measure in astronomy. The lunar distance is approximately, or 1.28 light-seconds; this is roughly 30 times Earth's diameter. A little less than 400 lunar distances make up an astronomical unit.

Siriometer

The siriometer is an obsolete astronomical measure equal to one million astronomical units, i.e., one million times the average distance between the Sun and Earth.[10] This distance is equal to about 15.8 light-years, 149.6 Pm, or 4.8 parsecs, and is about twice the distance from Earth to the star Sirius.[11]

Cubit

The cubit is, among others, a unit used in the Bible for measuring the size of Noah's Ark and of the Ark of the Covenant. Cubits of various lengths were used in Antiquity by various peoples, not only the Hebrews. One cubit is originally the length from someone's elbow to the tip of their middle finger; it usually translates to approximately half a metre ±10%, with an ancient Roman cubit being as long as 120 cm.

One cubit was equal to 6–7 palms, one palm being the width of a hand not including the thumb.

Vee

In groff/troff and specifically in the included traditional manuscript macro set ms, the vee (v) is a unit of vertical distance often—but not always—corresponding to the height of an ordinary line of text.[12]

Area

Barn

See main article: Barn (unit). One barn is 10−28 square metres, about the cross-sectional area of a uranium nucleus. The name probably derives from early neutron-deflection experiments, when the uranium nucleus was described, and the phrases "big as a barn" and "hit a barn door" were used. Barn are typically used for cross sections in nuclear and particle physics. Additional units include the microbarn (or "outhouse")[13] and the yoctobarn (or "shed").[14] [15]

Kuang

A Kuang is a traditional Chinese unit of area used in sampling, equal to 0.11 square metres or one square Chinese foot.[16]

Brass or square

One brass is exactly 100ft2 area (used in measurement of work done or to be done, such as plastering, painting, etc.). The same word is used, however, for 100ft3 of estimated or supplied loose material, such as sand, gravel, rubble, etc. This unit is prevalent in the construction industry in India.[17] [18]

The same area is called a square in the construction industry in North America,[19] and was historically used in Australia by real estate agents. A roof's area may be calculated in square feet, then converted to squares.

Cow's grass

In Ireland, before the 19th century, a "cow's grass" was a measurement used by farmers to indicate the size of their fields. A cow's grass was equal to the amount of land that could produce enough grass to support a cow.[20] [21]

Football field (area)

A football pitch, or field, can be used as a man-in-the-street unit of area.[22] [23] The standard FIFA football pitch for international matches is 105m (344feet) long by 68m (223feet) wide (7140abbr=onNaNabbr=on); FIFA allows for a variance of up to 5abbr=onNaNabbr=on in length in either direction and 7abbr=onNaNabbr=on more or 4abbr=onNaNabbr=on less in width (and larger departures if the pitch is not used for international competition), which generally results in the association football pitch generally only being used for order of magnitude comparisons.[24]

An American football field, including both end zones, is 360by, or 57600square feet (0.535ha). A Canadian football field is 65yd wide and 110yd long with end zones adding a combined 40yd to the length, making it 87750square feet or 0.8215ha.

An Australian rules football field may be approximately 150m (490feet) (or more) long goal to goal and 135m (443feet) (or more) wide, although the field's elliptical nature reduces its area to a certain extent. A 150by football field has an area of approximately 15900m2, twice the area of a Canadian football field and three times that of an American football field.

Morgen

See main article: Morgen. A morgen ("morning" in Dutch and German) was approximately the amount of land tillable by one man behind an ox in the morning hours of a day. This was an official unit of measurement in South Africa until the 1970s, and was defined in November 2007 by the South African Law Society as having a conversion factor of 1 morgen = .[25] This unit of measure was also used in the Dutch colonial province of New Netherland (later New York and parts of New England).[26] [27]

Countries, regions, and cities

The area of a familiar country, state or city is often used as a unit of measure, especially in journalism.

Wales

Equal to 20,779 km2 (8,023 sq mi), the country of Wales is used in phrases such as "an area the size of Wales"[28] or "twice the area of Wales".[29] [30] England is 6.275 times the size of Wales, and Scotland is roughly four times the size of Wales. Ireland is four times as large as Wales, and France is about twenty-five times larger.

The British comedy show The Eleven O'Clock Show parodied the use of this measurement, by introducing a news article about an earthquake in Wales, stating that an area the size of Wales was affected. The Radio 4 programme More or Less introduced the idea of "kilowales" – an area 1,000 times the size of Wales. The Register introduced the nanowales (20.78 m2).[31]

The measurement has been adopted by rainforest conservation charity Size of Wales, aiming to conserve an area of rainforest equating to the area of Wales. On 1 March 2013, the charity announced that they had succeeded[32] in conserving an area of rainforest the size of Wales and will continue to operate to sustain and increase the protected area.[33]

United States

In the United States, the area of the smallest state, Rhode Island (1545disp=orNaNdisp=or); the largest of the contiguous 48 states, Texas (268601disp=orNaNdisp=or); and less commonly Alaska (656425disp=orNaNdisp=or), the largest of all 50 states, are used in a similar fashion. For example, Antarctica's Larsen B ice shelf was approximately the size of Rhode Island until it broke up in 2002. Other areas may be described like this, too, like in the 1979 movie The China Syndrome when radiation is expected to contaminate "an area the size of Pennsylvania". The island of Manhattan (22.83disp=orNaNdisp=or) is a common reference.

The US Central Intelligence Agency uses Washington, D.C. (61.4disp=orNaNdisp=or) as a comparison for city-sized objects.[34]

Other countries

In the Netherlands, its smallest province, Utrecht (1386abbr=onNaNabbr=on), is often used as a comparison for regions in general.

The country of Belgium (30528disp=orNaNdisp=or) has also often been used when comparing areas, to the point where it has been regarded as a meme[35] and where there is a website dedicated to notable areas which have been compared to that of Belgium.

The Isle of Wight (380km2), an island off the south coast of mainland England, is commonly used to define smaller areas. It has sometimes been used in attempts to examine whether a certain amount of a given object or group would fit in a space its size; in 2018, it was estimated that approximately 2.6 billion people could fit on the Isle of Wight, at a population density of six people per square metre.[36] In Hong Kong, the 19-hectare Victoria Park is used to define smaller areas.

In Denmark, the outlying island of Bornholm (588km2) is often used to describe the size of an area.

In Germany, the state of Saarland (2569.69disp=orNaNdisp=or) is often used to define areas.[37]

In Brazil, it is common to compare relatively small areas to the state of Sergipe (21910.4disp=orNaNdisp=or), the smallest in the country. Smaller areas are sometimes compared to the cities of São Paulo (1521.11disp=orNaNdisp=or) or Rio de Janeiro (1221disp=orNaNdisp=or).

Volume

Metric ounce

A metric ounce is an approximation of the imperial ounce, US dry ounce, or US fluid ounce. These three customary units vary. However, the metric ounce is usually taken as 25 or 30 ml when volume is being measured, or grams when mass is being measured.

The US Food and Drug Administration (FDA) defines the "food labeling ounce" as 30 ml, slightly larger than the 29.6 ml fluid ounce.[38]

Several Dutch units of measurement have been replaced with informal metric equivalents, including the ons or ounce. It originally meant of a pound, or a little over 30 grams depending on which definition of the pound was used, but was redefined as 100 grams when the country metricated.[39]

Shot

See main article: Shot glass. The shot is a liquid volume measure that varies from country to country and state to state depending on legislation. It is routinely used for measuring strong liquor or spirits when the amount served and consumed is smaller than the more common measures of alcoholic "drink" and "pint". There is a legally defined maximum size of a serving in some jurisdictions. The size of a "single" shot is 20ml60ml. The smaller "pony" shot is 20ml30ml. According to Encyclopædia Britannica Almanac 2009, a pony is 0.75 fluid ounces of liquor.[40] According to Wolfram Alpha, one pony is 1 U.S. fluid ounce.[41] "Double" shots (surprisingly not always the size of two single shots, even in the same place) are 40ml100ml. In the UK, spirits are sold in shots of either 25 ml (approximating the old fluid ounce) or 35 ml.[42]

Board foot or super foot

See main article: Board foot. A board foot is a United States and Canadian unit of approximate volume, used for lumber. It is equivalent to (144disp=or0disp=or). It is also found in the unit of density pounds per board foot. In Australia and New Zealand the terms super foot or superficial foot were formerly used for this unit. The exact volume of wood specified is variable and depends on the type of lumber. For planed lumber the dimensions used to calculate board feet are nominal dimensions, which are larger than the actual size of the planed boards. See Dimensional lumber for more information on this.

Hoppus foot

A system of measure for timber in the round (standing or felled), now largely superseded by the metric system except in measuring hardwoods in certain countries. Its purpose is to estimate the value of sawn timber in a log, by measuring the unsawn log and allowing for wastage in the mill. Following the so-called "quarter-girth formula" (the square of one quarter of the circumference in inches multiplied by of the length in feet), the notional log is four feet in circumference, one inch of which yields the hoppus board foot, 1 foot yields the hoppus foot, and 50 feet yields a hoppus ton. This translates to a hoppus foot being equal to 1.273ft3. The hoppus board foot, when milled, yields about one board foot. The volume yielded by the quarter-girth formula is 78.54% of cubic measure (i.e. 1 ft3 = 0.7854 h ft; 1 h ft = 1.273 ft3).[43]

Cubic ton

See main article: Cubic ton. A cubic ton is an antiquated measure of volume, varying based on the commodity from about 16to. It is now only used for lumber, for which one cubic ton is equivalent to 40ft3.

Cord and rick

See main article: Cord (unit). The cord is a unit of measure of dry volume used in Canada and the United States to measure firewood and pulpwood. A cord is the amount of wood that, when "ranked and well stowed" (arranged so pieces are aligned, parallel, touching and compact), occupies a volume of 128cuft.[44] This corresponds to a well-stacked woodpile, 4 feet deep by 4 feet high by 8 feet wide, or any other arrangement of linear measurements that yields the same volume. A more unusual measurement for firewood is the "rick" or face cord. It is stacked 16inches deep with the other measurements kept the same as a cord, making it of a cord; however, regional variations mean that its precise definition is non-standardized.[45]

Twenty-foot equivalent unit

See main article: Twenty-foot equivalent unit. The twenty-foot equivalent unit is the volume of the smallest standard shipping container. It is equivalent to 1360cuft. Larger intermodal containers are commonly described in multiples of TEU, as are container ship capacities.

Acre-foot

See main article: Acre-foot. An acre-foot is a unit of volume commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water[46] and river flows. It is defined by the volume of one acre of surface area to a depth of one foot. 435600NaN0.

Casual units

Many well-known objects are regularly used as casual units of volume. They include:

Double-decker bus: The approximate volume of a double-decker bus, abbreviated to DDB, has been used informally to describe the size of hole created by a major sewer collapse. For example, a report might refer to "a 4 DDB hole".[47]
Olympic-size swimming pool: For larger volumes of liquid, one measure commonly used in the media in many countries is the Olympic-size swimming pool.[48] A 50m×25mm (160feet×82feetm) Olympic swimming pool, built to the FR3 minimum depth of 2m (07feet) would hold 2500m2. The US National Institute of Standards and Technology (NIST) defines the Olympic swimming pool as 1 million litres, which is the approximate volume of the smaller FR2 pool.[49]
Royal Albert Hall: The Royal Albert Hall, a large concert hall, is sometimes used as a unit of volume in the UK, for example when referring to volumes of rubbish placed in landfill.[50] It is famously used in the line "Now they know how many holes it takes to fill the Albert Hall." in The Beatles song "A Day in the Life".[51] The volume of the auditorium is between 3 and 3.5 million cubic feet (between 85,000 and 99,000 cubic metres).[52]
Melbourne Cricket Ground: A common measure of volume in Australia, and in the state of Victoria in particular, is the Melbourne Cricket Ground, the largest stadium in Australia and 13th largest in the world.[53] The volume of the Melbourne Cricket Ground is 1,574,000 cubic metres, or about 630 Olympic swimming pools.[54] Its seating capacity (100,000) is also used as a unit measure of the number of people.
A unit of volume used in Australia for water. One Sydney Harbour is the amount of water in Sydney Harbour: approximately 562 gigalitres (562,000,000 cubic metres, or 0.562 of a cubic kilometre); or in terms of the more unusual measures above, about 357 Melbourne Cricket Grounds, 238,000 Olympic Swimming pools, or 476,000 acre-feet.[55] [56] [57]
The Grand Canyon: With a volume measure approximately 4 orders of magnitude greater than Sydney Harbour, the volume of the Grand Canyon may be used to visualize even larger things, like the magma chamber underneath Yellowstone[58] and other things.[59] [60] According to the National Park Service, the volume of the Grand Canyon is 4.17e12m3[61] which is 4.17e12m3 (4.17e12m3).

Flow rate

Miner's inch

See main article: Miner's inch. The volume of water which flows in one unit of time through an orifice of one square inch area. The size of the unit varies from one place to another.

Mass

Electronvolt mass

It is common in particle physics to use eV/c2 as a unit of mass. Here, eV (electronvolt) is a unit of energy (the kinetic energy of an electron accelerated over one volt,  joules), and c is the speed of light in vacuum. Energy and mass are related through E = mc2. This definition is useful for a linear particle accelerator when accelerating electrons.

In many systems of natural units, so the c is dropped and eV itself becomes a unit of mass.

Bag of cement and bag mix

The mass of an old bag of cement was one hundredweight (112lb). The amount of material that an aircraft could carry into the air is often visualised as the number of bags of cement that it could lift. In the concrete and petroleum industry, however, a bag of cement is defined as because it has an apparent volume close to 1cuft.[62] When ready-mix concrete is specified, a "bag mix" unit is used as if the batching company mixes 5 literal bags of cement per cubic yard (or cubic metre) when a "5 bag mix" is ordered.

Grave

In 1793, the French term "grave" (from "gravity") was suggested as the base unit of mass for the metric system. In 1795, however, the name "kilogramme" was adopted instead.

Jupiter

When reporting on the masses of extrasolar planets, astronomers often discuss them in terms of multiples of Jupiter's mass (= 1.9  kg).[63] For example, "Astronomers recently discovered a planet outside our Solar System with a mass of approximately 3 Jupiters." Furthermore, the mass of Jupiter is nearly equal to one thousandth of the mass of the Sun.

Sun

Solar mass (=) is also often used in astronomy when talking about masses of stars or galaxies; for example, Alpha Centauri A has the mass of 1.1 suns, and the Milky Way has a mass of approximately .

Solar mass also has a special use when estimating orbital periods and distances of 2 bodies using Kepler's laws: a3 = MtotalT2, where a is length of semi-major axis in AU, T is orbital period in years and Mtotal is the combined mass of objects in . In case of planet orbiting a star, Mtotal can be approximated to mean the mass of the central object. More specifically in the case of Sun and Earth the numbers reduce to Mtotal ~ 1, a ~ 1 and T ~ 1.

Time

Light-distance

George Gamow discussed measurements of time such as the "light-mile" and "light-foot", the time taken for light to travel the specified unit distance, defined by "reversing the procedure" used in defining a light-year.[64] A light-foot is roughly one nanosecond.[65]

Shake

In nuclear engineering and astrophysics contexts, the shake is sometimes used as a conveniently short period of time. 1 shake is defined as 10 nanoseconds.[66]

Jiffy

In computing, the jiffy is the duration of one tick of the system timer interrupt. Typically, this time is 0.01 seconds, though in some earlier systems (such as the Commodore 8-bit machines) the jiffy was defined as of a second, roughly equal to the vertical refresh period (i.e. the field rate) on NTSC video hardware (and the period of AC electric power in North America).

Microfortnight

One unit derived from the FFF system of units is the microfortnight, one millionth of the fundamental time unit of FFF, which equals 1.2096 seconds. This is a fairly representative example of "hacker humor",[67] and is occasionally used in operating systems; for example, the OpenVMS TIMEPROMPTWAIT parameter is measured in microfortnights.[68]

Sidereal day

The sidereal day is based on the Earth's rotation rate relative to fixed stars, rather than the Sun. A sidereal day is approximately 23 hours, 56 minutes, 4.0905 SI seconds.

Decimal time systems

See main article: Decimal time. The measurement of time is unique in SI in that while the second is the base unit, and measurements of time smaller than a second use prefixed units smaller than a second (e.g. microsecond, nanosecond, etc.), measurements larger than a second instead use traditional divisions, including the sexagesimal-based minute and hour as well as the less regular day and year units.

SI allows for the use of larger prefixed units based on the second, a system known as metric time, but this is seldom used, since the number of seconds in a day (86,400 or, in rare cases, 86,401) negate one of the metric system's primary advantages: easy conversion by multiplying or dividing by powers of ten.

There have been numerous proposals and usage of decimal time, most of which were based on the day as the base unit, such that the number of units between any two events that happen at the same time of day would be equal to the number of days between them multiplied by some integer power of ten. In dynastic China, the was a unit that represented of a day (it has since been redefined to of a day, or 15 minutes). In France, a decimal time system in place from 1793 to 1805 divided the day into 10 hours, each divided into 100 minutes, in turn each divided into 100 seconds; the French Republican Calendar further extended this by assembling days into ten-day "weeks".

Ordinal dates and Julian days, the latter of which has seen use in astronomy as it is not subject to leap year complications, allow for the expression of a decimal portion of the day.[69] In the mid-1960s, to defeat the advantage of the recently introduced computers for the then popular rally racing in the Midwest, competition lag times in a few events were given in centids ( day, 864 seconds, 14.4 minutes), millids ( day, 86.4 seconds), and centims ( minute, 0.6 seconds) the latter two looking and sounding a bit like the related units of minutes and seconds. Decimal time proposals are frequently used in fiction, often in futuristic works.

In addition to decimal time, there also exist binary clocks and hexadecimal time.

The Swatch Internet Time system is based on Decimal time.

Many mechanical stopwatches are of the 'decimal minute' type. These split one minute into 100 units of 0.6s each. This makes addition and subtraction of times easier than using regular seconds.

Sol

See main article: Sol (day on Mars). The United States-based NASA, when conducting missions to the planet Mars, has typically used a time of day system calibrated to the mean solar day on that planet (known as a "sol"), training those involved on those missions to acclimate to that length of day, which is 88,775 SI seconds, or 2,375 seconds (about 39 minutes) longer than the mean solar day on Earth. NASA's Martian timekeeping system (instead of breaking down the sol into 25×53×67 or 25×67×53 SI second divisions) slows down clocks so that the 24-hour day is stretched to the length of that on Mars; Martian hours, minutes and seconds are thus 2.75% longer than their SI-compatible counterparts.[70] [71]

The Darian calendar is an arrangement of sols into a Martian year. It maintains a seven-sol week (retaining Sunday through Saturday naming customs), with four weeks to a month and 24 months to a Martian year, which contains 668 or 669 sols depending on leap years. The last Saturday of every six months is skipped over in the Darian calendar.

Dog year

There are two diametrically opposed definitions of the dog year, primarily used to approximate the equivalent age of dogs and other animals with similar life spans. Both are based upon a popular myth regarding the aging of dogs that states that a dog ages seven years in the time it takes a human to age one year.

In fact, the aging of a dog varies by breed (larger breeds tend to have shorter lifespans than small and medium-sized breeds); dogs also develop faster and have longer adulthoods relative to their total life span than humans. Most dogs are sexually mature by 1 year old, which corresponds to perhaps 13 years old in humans. Giant dog breeds and bulldogs tend to have the strongest linear correspondence to human aging, with longer adolescences and shorter overall lifespans; such breeds typically age about nine times as fast as humans throughout their lives.[74]

Galactic year

See main article: Galactic year. The galactic year, GY, is the time it takes the solar system to revolve once around the galactic core, approximately 250 million years (megaannum or "Ma"). It is a convenient unit for long-term measurements. For example, oceans appeared on Earth after 4 GY, life is detectable at 5 GY, and multicellular organisms first appeared at 15 GY. The age of the Earth is estimated at 20 GY.[75] This use of GY is not to be confused with Gyr for gigayear or Gy for Gray (unit).

KerMetric time

KerMetric time is a concept that divides the day into 100 equal parts called kermits. Each kermit is equivalent to 14.4 minutes. More precise time can be counted by dividing by 1000 or even 10000. The name kermit came from a combination of the surname of Dr. Larkin Kerwin, president of the National Research Council in 1983, with the word "metric". The original working model of KerMetric time as conceived by W. Thayer of NRC was assembled by the designated Clock Construction Team of John Phillips, Ron Hawkins, Les Moore, and Willie Thayer in 1983.[76]

Moment

See also: atom (unit). A moment was a medieval unit of time. The movement of a shadow on a sundial covered 40 moments in a solar hour. An hour in this case meant one twelfth of the period between sunrise and sunset. The length of a solar hour depended on the length of the day, which in turn varied with the season, so the length of a moment in modern seconds was not fixed, but on average, a moment corresponded to 90 seconds.

Thirds, fourths

The term "minute" usually means of an hour, coming from "a minute division of an hour". The term "second" comes from "the second minute division of an hour", as it is of a minute, or of of an hour. While usually sub-second units are represented with SI prefixes on the second (e.g. milliseconds), this system can be extrapolated further, such that a "Third" would mean of a second (16.7 milliseconds), and a "Fourth" would mean of a third (278 microseconds), etc. These units are occasionally used in astronomy to denote angles.[77]

Angular measure

Furman

The Furman is a unit of angular measure equal to of a circle, or just under 20 arcseconds. It is named for Alan T. Furman, the American mathematician who adapted the CORDIC algorithm for 16-bit fixed-point arithmetic sometime around 1980.[78] 16 bits give a resolution of 216 = 65,536 distinct angles.

Binary degree, binary radian, brad

A related unit of angular measure equal to of a circle, represented by 8 bits, has found some use in machinery control where fine precision is not required, most notably crankshaft and camshaft position in internal combustion engine controllers, and in video game programming. There is no consensus as to its name, but it has been called the 8-Bit Furman, the Small Furman, the Furboy and more recently, the miFurman, (milli-binary-Furman). These units are convenient because they form cycles: for the 8-bit unit, the value overflows from 255 to 0 when a full circle has been traversed, so binary addition and subtraction work as expected. Measures are often made using a Gray code, which is trivially converted into more conventional notation. Its value is equivalent to Tau/256 radians, or about 0.0245436926 radians.

Grade (also grad, gradian, gon)

See main article: Grad (angle). Coordinates were measured in grades on official French terrestrial ordnance charts from the French revolution well into the 20th century. 1 grade (or in modern symbology, 1 gon) = 0.9° or 0.01 right angle. One advantage of this measure is that the distance between latitude lines 0.01 gon apart at the equator is almost exactly 1 kilometre. It would be exactly 1 km if the original definition of 1 metre = quarter-meridian had been adhered to. One disadvantage is that common angles like 30° and 60° are expressed by fractional values (and respectively) so this "decimal" unit failed to displace the "sexagesimal" units equilateral-vertex – degree – minute – second invented by Babylonian astronomers.

Mils, strecks

Mils and strecks are small units of angle used by various military organizations for range estimation and translating map coordinates used for directing artillery fire.[79] The exact size varies between different organizations: there are 6400 NATO mils per turn (1 NATO mil = 0.982 mrad), or 6000 Warsaw pact mils per turn (1 Warsaw pact mil = 1.047 mrad). In the Swedish military, there are 6300 strecks per turn (1 streck = 0.997 mrad).

MERU (Milli Earth Rate Unit)

The MERU, or Milli Earth Rate Unit, is an angular velocity equal to 1/1000 of Earth's rotation rate. It was introduced by MIT's Instrumentation Laboratories (now Draper Labs) to measure the performance of inertial navigation systems.[80] One MERU = [81] or about 0.2625 milliradians/hour.

Energy

Gasoline gallon equivalent

See main article: Gasoline gallon equivalent. In 2011, the United States Environmental Protection Agency introduced the gallon gasoline equivalent as a unit of energy because their research showed most U.S. citizens do not understand the standard units. The gallon gasoline equivalent is defined as 33.7 kWh,[82] or about 1.213 joules.

Efficiency / fuel economy can be given as miles per gallon gasoline equivalent.

Tons of TNT equivalent

See main article: TNT equivalent. The energy of various amounts of the explosive TNT (kiloton, megaton, gigaton) is often used as a unit of explosion energy, and sometimes of asteroid impacts and violent explosive volcanic eruptions. One ton of TNT produces 4.184 joules, or (by arbitrary definition) exactly  thermochemical calories (approximately 3.964 BTU). This definition is only loosely based on the actual physical properties of TNT.

Hiroshima bomb and Halifax explosion

The energy released by the Hiroshima bomb explosion (about 15 kt TNT equivalent, or 6 J) is often used by geologists as a unit when describing the energy of earthquakes, volcanic eruptions, and asteroid impacts.

Prior to the detonation of the Hiroshima bomb, the size of the Halifax Explosion (about 3 kt TNT equivalent, or 1.26 J), was the standard for this type of relative measurement. Each explosion had been the largest known artificial detonation to date.[83]

Quad

A quad is a unit of energy equal to  BTUs, or approximately 1.055 J (slightly over one exajoule). It is suitably large to quantify energy usage by nations or by the planet as whole using everyday numbers. For example, in 2004, US energy consumption was about 100 Q/year, while demand worldwide was about 400 Q/year.[84]

Foe

A foe is a unit of energy equal to  joules (≈9.478 BTU) that was coined by physicist Gerry Brown of Stony Brook University. To measure the staggeringly immense amount of energy produced by a supernova, specialists occasionally use the "foe", an acronym derived from the phrase [ten to the power of] fifty-one ergs, or  ergs. This unit of measure is convenient because a supernova typically releases about one foe of observable energy in a very short period of time (which can be measured in seconds).

Other metric-compatible scales

Power: Ton of refrigeration

See main article: Ton of refrigeration. The rate at which heat is removed by melting 1ST of ice in 24 hours is called a ton of refrigeration, or even a ton of cooling. This unit of refrigeration capacity came from the days when large blocks of ice were used for cooling, and is still used to describe the heat-removal capabilities of refrigerators and chillers today. One ton of refrigeration is exactly equal to 12,000 BTU/h, or 3.517 kW.

Luminous flux: watt equivalent

With the phaseout of the incandescent lamp in the United States and European Union in the early 21st century, manufacturers and sellers of more energy-efficient lamps have compared the visible light output of their lamps to commonly used incandescent lamp sizes with the watt equivalent or watt incandescent replacement (usually with a lowercase w as a unit symbol, as opposed to capital W for the actual wattage). 1 watt incandescent replacement corresponds to 15 lumens. Thus, a 72-watt halogen lamp, a 23-watt compact fluorescent lamp and a 14-watt light-emitting diode lamp, all of which emit 1500 lumens of visible light, are all marketed as "100 watt incandescent replacement" (100w).

Flow: Amazon River

The volume of discharge of the Amazon River sometimes used to describe large volumes of water flow such as ocean currents. The unit is equivalent to 216,000 m3/s.[85]

Flow: Sverdrup

One Sverdrup (Sv) is equal to 1,000,000 cubic metres per second (264,000,000 USgal/s). It is used almost exclusively in oceanography to measure the volumetric rate of transport of ocean currents.

Energy intensity

The langley (symbol Ly) is used to measure solar radiation or insolation. It is equal to one thermochemical calorie per square centimetre (4.184 J/m2 or ≈3.684 BTU/sq ft) and was named after Samuel Pierpont Langley. Its symbol should not be confused with that for the light-year, ly.

Kinematic viscosity

One of the few CGS units to see wider use, one stokes (symbol S or St) is a unit of kinematic viscosity, defined as 1 cm2/s, i.e., 10−4 m2/s (≈1.08×10−3 sq ft/s).

Angular velocity

MERU (Milli Earth Rate Unit), an angular velocity equal to of Earth's rotation rate: 1 MERU = 0.015 degrees/hour ≈ 0.072921 microradian/second. Sometimes used to measure the angular drift rate of an inertial navigation system.[86]

Electromagnetic flux

In radio astronomy, the unit of electromagnetic flux is the jansky (symbol Jy), equivalent to 10−26 watts per square metre per hertz (= 10−26 kg/s2 in base units, about 8.8×10−31 BTU/ft2). It is named after the pioneering radio astronomer Karl Jansky. The brightest natural radio sources have flux densities of the order of one to one hundred jansky.

Metre of water equivalent

See main article: Meter water equivalent. A material-dependent unit used in nuclear and particle physics and engineering to measure the thickness of shielding, for example around a nuclear reactor, particle accelerator, or radiation or particle detector. 1 mwe of a material is the thickness of that material that provides the equivalent shielding of one metre (≈39.4 in) of water.

This unit is commonly used in underground science to express the extent to which the overburden (usually rock) shields an underground space or laboratory from cosmic rays. The actual thickness of overburden through which cosmic rays must traverse to reach the underground space varies as a function of direction due to the shape of the overburden, which may be a mountain, or a flat plain, or something more complex like a cliff side. To express the depth of an underground space in mwe (or kmwe for deep sites) as a single number, the convention is to use the depth beneath a flat overburden at sea level that gives the same overall cosmic ray muon flux in the underground location.

Strontium unit: radiation dose

The strontium unit, formerly known as the Sunshine Unit (symbol S.U.), is a unit of biological contamination by radioactive substances (specifically strontium-90). It is equal to one picocurie of Sr-90 per gram of body calcium. Since about 2% of the human body mass is calcium, and Sr-90 has a half-life of 28.78 years, releasing 6.697+2.282 MeV per disintegration, this works out to about 1.065 grays per second. The permissible body burden was established at 1,000 S.U.

Banana equivalent dose

Bananas, like most organic material, naturally contain a certain amount of radioactive isotopes—even in the absence of any artificial pollution or contamination. The banana equivalent dose, defined as the additional dose a person will absorb from eating one banana, expresses the severity of exposure to radiation, such as resulting from nuclear weapons or medical procedures, in terms that would make sense to most people. This is approximately 78 nanosieverts – in informal publications one often sees this estimate rounded up to 0.1 μSv.

Flight-time equivalent dose

Natural background radiation typically increases with altitude above the earth's surface. Utilizing this phenomenon, dose resulting from radiological exposures can be expressed in units of flight-time. Flight-time equivalent dose is defined as the time spent in an aircraft at cruising altitude required to receive a radiological dose approximately equivalent to a radiological exposure such as a medical x-ray. One hour of flight-time is approximately equivalent to a dose of 0.004 millisieverts.

Molar mass of cellulose

In the pulp and paper industry, molar mass is traditionally measured with a method where the intrinsic viscosity (dL/g) of the pulp sample is measured in cupriethylenediamine (Cuen). The intrinsic viscosity [η] is related to the weight-average molar mass (in daltons) by the Mark-Houwink equation: [η] = 0.070 Mw0.70.[87] However, it is typical to cite [η] values directly in dL/g, as the "viscosity" of the cellulose, confusingly as it is not a viscosity.

Iodine, bromine and kappa number

In measuring unsaturation in fatty acids, the traditional method is the iodine number. Iodine adds stoichiometrically to double bonds, so their amount is reported in grams of iodine spent per 100 grams of oil. The standard unit is a dimensionless stoichiometry ratio of moles double bonds to moles fatty acid. A similar quantity, bromine number, is used in gasoline analysis.

In pulp and paper industry, a similar kappa number is used to measure how much bleaching a pulp requires. Potassium permanganate is added to react with the unsaturated compounds (lignin and uronic acids) in the pulp and back-titrated. Originally with chlorine bleaching the required quantity of chlorine could be then calculated, although modern methods use multiple stages. Since the oxidizable compounds are not exclusively lignin and the partially pulped lignin does not have a single stoichiometry, the relation between the kappa number and the precise amount of lignin is inexact.

Temperature: Gas Mark

Gas Mark is a temperature scale, predominantly found on British ovens, that scales linearly with temperature above 135 °C (Gas Mark 1) and scales with the log of Celsius below 135 °C.

Demography and epidemiology

Demography and quantitative epidemiology are statistical fields that deal with counts or proportions of people, or rates of change in these. Counts and proportions are technically dimensionless, and so have no units of measurement, although identifiers such as "people", "births", "infections" and the like are used for clarity. Rates of change are counts per unit of time and strictly have inverse time dimensions (per unit of time). In demography and epidemiology expressions such as "deaths per year" are used to clarify what is being measured.

Prevalence, a common measure in epidemiology is strictly a type of denominator data, a dimensionless ratio or proportion. Prevalence may be expressed as a fraction, a percentage or as the number of cases per 1,000, 10,000, or 100,000 in the population of interest.

Micromort

See main article: Micromort. A micromort is a unit of risk measuring a one-in-a-million probability of death (from micro- and mortality). Micromorts can be used to measure riskiness of various day-to-day activities. A microprobability is a one-in-a million chance of some event; thus a micromort is the microprobability of death. For example, smoking 1.4 cigarettes increases one's death risk by one micromort, as does traveling 230miles by car.

Numbers of people: Stadium capacities

The large numbers of people involved in demography are often difficult to comprehend. A useful visualisation tool is the audience capacity of large sports stadiums (often about 100,000). Often the capacity of the largest stadium in a region serves as a unit for a large number of people. For example, Uruguay's Estadio Centenario is often used in Uruguay,[88] [89] while in parts of the United States, Michigan Stadium is used in this manner.[90] In Australia, the capacity of the Melbourne Cricket Ground (about 100,000) is often cited in this manner. Hence the Melbourne Cricket Ground serves as both a measure of people and a unit of volume.[91] [92] [93]

Computer and information science

The growth of computing has necessitated the creation of many new units, several of which are based on unusual foundations.

Data volume

Volume or capacity of data is often compared to works of literature or large collections of writing. Popular units include the Bible, the Encyclopædia Britannica, phone books, the complete works of Shakespeare, and the Library of Congress.

When the Compact Disc began to be used as a data storage device as the CD-ROM, journalists often described the disc capacity (650 megabytes) by using the number of Christian Bibles that can be stored. The King James Version of the Bible in uncompressed plain 8-bit text contains about 4.5 million characters,[94] so a CD-ROM can store about 150 Bibles.

The print version of the Encyclopædia Britannica is another common data volume metric. It contains approximately 300 million characters,[95] so two copies would fit onto a CD-ROM and still have 50 megabytes (or about 11 bibles) left over.

The term Library of Congress is often used. It refers to the US Library of Congress. Information researchers have estimated that the entire print collections of the Library of Congress represent roughly 10 terabytes of uncompressed textual data.[96]

Nibble

A measure of quantity of data or information, the "nibble" (sometimes spelled "nybble" or "nybl") is normally equal to 4 bits, or one half of the common 8-bit byte. The nibble is used to describe the amount of memory used to store a digit of a number stored in binary-coded decimal format, or to represent a single hexadecimal digit. Less commonly, 'nibble' may be used for any contiguous portion of a byte of specified length, e.g. "6-bit nibble"; this usage is most likely to be encountered in connection with a hardware architecture in which the word length is not a multiple of 8, such as older 36-bit minicomputers.

FLOPS

See main article: FLOPS. In computing, FLOPS (FLoating point Operations Per Second) is a measure of a computer's computing power. It is also common to see measurements of kilo, mega, giga, and teraFLOPS.

It is also used to compare the performance of computers in practice.[97]

BogoMips

See main article: BogoMips. A measure to determine the CPU speed. It was invented by Linus Torvalds and is nowadays present on every Linux operating system. However, it is not a meaningful measure to assess the actual CPU performance.

KLOC

A computer programming expression, the K-LOC or KLOC, pronounced kay-lok, standing for "kilo-lines of code", i.e., thousand lines of code. The unit was used, especially by IBM managers,[98] to express the amount of work required to develop a piece of software. Given that estimates of 20 lines of functional code per day per programmer were often used, it is apparent that 1 K-LOC could take one programmer as long as 50 working days, or 10 working weeks. This measure is no longer in widespread use because different computer languages require different numbers of lines to achieve the same result (occasionally the measure "assembly equivalent lines of code" is used, with appropriate conversion factors from the language actually used to assembly language).

Error rates in programming are also measured in "Errors per K-LOC", which is called the defect density. NASA's SATC is one of the few organizations to claim zero defects in a large (>500K-LOC) project, for the space shuttle software.

An alternative measurement was defined by Pegasus Mail author David Harris: the "WaP" is equivalent to 71,500 lines of program code, because that number of lines is the length of one edition of Leo Tolstoy's War and Peace.[99]

Ticks

The "tick" is the amount of time between timer interrupts generated by the timer circuit of a CPU. The amount of time is processor-dependent.[100] [101]

Other

Centipawn

Chess software frequently uses centipawns internally or externally as a unit measuring how strong each player's situation position is, and hence also by how much one player is beating the other, and how strong a possible move is.[102] 100 centipawns = the value of 1 pawn – more specifically, something like the average value of the pawns at the start of the game, as the actual value of pawns depends on their position. Loss of a pawn will therefore typically lose that player 100 centipawns. The centipawn is often used for comparing possible moves, as in a given position, chess software will often rate the better of two moves within a few centipawns of each other.

Garn

The garn is NASA's unit of measure for symptoms resulting from space adaptation syndrome, the response of the human body to weightlessness in space, named after US Senator Jake Garn, who became exceptionally spacesick during an orbital flight in 1985. If an astronaut is completely incapacitated by space adaptation syndrome, he or she is under the effect of one garn of symptoms.[103]

Mother Cow Index

Formerly used in real estate transactions in the American Southwest, it was the number of pregnant cows an acre of a given plot of land could support. It acted as a proxy for the agricultural quality, natural resource availability, and arability of a parcel of land.[104]

Nines

See main article: Nine (purity). Numbers very close to, but below one are often expressed in "nines" (N – not to be confused with the unit newton), that is in the number of nines following the decimal separator in writing the number in question. For example, "three nines" or "3N" indicates 0.999 or 99.9%, "four nines five" or "4N5" is the expression for the number 0.99995 or 99.995%.[105] [106] [107]

Typical areas of usage are:

Pain

See also: Pain scale, Dolorimeter, Pain and Nociception. The dol (from the Latin word for pain, dolor) is a unit of measurement for pain. James D. Hardy, Herbert G. Wolff, and Helen Goodell of Cornell University proposed the unit based on their studies of pain during the 1940s and 1950s. They defined one dol to equal a just-noticeable difference in pain. The unit never came into widespread use and other methods are now used to assess the level of pain experienced by patients.

The Schmidt sting pain index and Starr sting pain index are pain scales rating the relative pain caused by different hymenoptera stings. Schmidt has refined his pain index (with a 1–4 scale) with extensive anecdotal experience, culminating in a paper published in 1990 which classifies the stings of 78 species and 41 genera of Hymenoptera. The Starr sting pain scale uses the same 1–4 scale.

Pepper heat

ASTA pungency unit

The ASTA (American Spice Trade Association) pungency unit is based on a scientific method of measuring chili pepper "heat". The technique utilizes high-performance liquid chromatography to identify and measure the concentrations of the various compounds that produce a heat sensation. Scoville units are roughly the size of pungency units while measuring capsaicin, so a rough conversion is to multiply pungency by 15 to obtain Scoville heat units.[108]

Scoville heat unit

The Scoville scale is a measure of the hotness of a chili pepper. It is the degree of dilution in sugar water of a specific chili pepper extract when a panel of 5 tasters can no longer detect its "heat".[109] Pure capsaicin (the chemical responsible for the "heat") has 16 million Scoville heat units.

Potrzebie

The widely-read MAD Magazine made extensive use, as a running gag, of the Potrzebie system of units, which included units of length, mass etc.

Proof: alcohol concentration

See main article: Alcohol proof. Up to the 20th century, alcoholic spirits were assessed in the UK by mixing with gunpowder and testing the mixture to see whether it would still burn; spirit that just passed the test was said to be at 100° proof. The UK now uses percentage alcohol by volume (ABV) at 20C, where spirit at 100° proof is approximately 57.15% ABV. In the US, "proof number" is defined as twice the ABV at 60F.[110]

Savart

The savart is an 18th-century unit for measuring the frequency ratio of two sounds. It is equal to of a decade (not to be confused with the time period equal to 10 years). The cent is preferred for musical use.

Telecommunications traffic volume

See main article: Erlang (unit). The erlang, named after A. K. Erlang, as a dimensionless unit is used in telephony as a statistical measure of the offered intensity of telecommunications traffic on a group of resources. Traffic of one erlang refers to a single resource being in continuous use, or two channels being at fifty percent use, and so on, pro rata. Much telecommunications management and forecasting software uses this.

X-ray intensity

See main article: Crab (unit). The crab is defined as the intensity of X-rays emitted from the Crab Nebula at a given photon energy up to 30 kiloelectronvolts. The Crab Nebula is often used for calibration of X-ray telescopes. For measuring the X-ray intensity of a less energetic source, the milliCrab (mCrab) may be used.

One crab is approximately 24 pW/m2.

See also

External links

Bibliography

Notes and References

  1. Web site: Distance - Valve Developer Community . 29 November 2020 . Maps, architecture and prop models use a scale of 1 foot = 16 units..
  2. Web site: Equestrian Federation of Australia National Measuring Scheme Effective from 1 January 2002 and amended in March 2002 . https://web.archive.org/web/20060826125716/http://www.equestrian.org.au/site/equestrian/national/downloads/content/attachments/rules/02%20Mch-Nat%20Measuring%20Rules.pdf . 26 August 2006 . . March 2002 . www.equestrian.org.au/ . Equestrian Federation of Australia . 27 February 2014.
  3. Web site: The "Hand" Measurement for Horses. Ministry of Agriculture, Food and Rural Affairs, Ontario, Canada. 30 June 2011 . https://web.archive.org/web/20110822161506/http://www.omafra.gov.on.ca/english/livestock/horses/facts/info_hands.htm. 22 August 2011.
  4. Web site: Rear Admiral Grace Murray Hopper. 4 May 2006 . US Navy.
  5. Web site: Nanoseconds Associated with Grace Hopper. National Museum of American History.
  6. Web site: BBC TV Centre . History of Television Studios in London . Measurements are in metric feet (30cm)....
  7. Web site: Horse Racing Spread Betting – Get Started . Spreadex . 10 August 2019.
  8. Web site: 2015 NFL Rulebook . https://web.archive.org/web/20150824155322/http://operations.nfl.com/the-rules/2015-nfl-rulebook . 24 August 2015 . NFL Football Operations.
  9. Web site: Manhattan distance. xlinux.nist.gov.
  10. Book: Charlier. C. V. L.. Carl Charlier. Lectures on Stellar Statistics. 1921. 1921lss..book.....C.
  11. Beech. Martin. The reluctant parsec and the overlooked light-year. The Observatory. 128. 489. 2008. 2008Obs...128..489B.
  12. Web site: The GNU Troff Manual .
  13. Web site: An Exceptional Nuclear Glossary . Nuclearglossary.com . 25 November 2006 . 8 April 2011 . 27 June 2016 . https://web.archive.org/web/20160627084654/http://www.nuclearglossary.com/abcs/nuclearglossary_O.html#outhouse .
  14. Web site: Russ Rowlett . 1 September 2004 . Units: S . How Many? A Dictionary of Units of Measurement . . 14 December 2009.
  15. Book: Green, Jonathon. Dictionary of Jargon. 14 December 2009. December 1987. Routledge Kegan & Paul. 978-0-7100-9919-8. 487.
  16. Moore . Julia L . Liang . Liang . Remais . Justin V . Cautioning the use of degree-day models for climate change projections in the presence of parametric uncertainty. . Ecological Applications . December 2012 . 22 . 1051–0761 . 2237–2247 . 10.1890/12-0127.1 . 23387122 . 3816756 . 2012EcoAp..22.2237M .
  17. Web site: Chart. gardentia.net. 1 May 2018.
  18. News: Mumbai builders hit sand trap. Sanjay. Jog. 12 February 2010. 1 May 2018. Business Standard. Business Standard India.
  19. Web site: Units of Measurements. https://web.archive.org/web/20031018185707/http://www.p1m.com/um.htm. 18 October 2003. 18 October 2003. 1 May 2018.
  20. Book: Kelly, John. The Graves are Walking: The Great Famine and Saga of the Irish People. 15. Henry Holt & Co.. 2012.
  21. Book: Foster, Thomas Campbell. Letters on the Condition of the People of Ireland. 1846. Chapman and Hall. en. The land is not let by the acre, but by what is termed a "cow's grass" — so many "cows' grass" to a farm. A "cow's grass" is a measure of land; usually it means as much mountain grazing-land as will keep a cow during the summer, and as much arable-land as will keep the cow-house in fodder during the winter.. 104.
  22. News: Nigerian crash airline grounded. 30 October 2006. news.bbc.co.uk.
  23. News: Grass fire strikes the Malverns. 25 July 2006. news.bbc.co.uk.
  24. Web site: Goal-line technology put on ice . fifa.com . 8 March 2008 . https://web.archive.org/web/20101223112215/http://www.fifa.com/aboutfifa/federation/bodies/media/newsid%3D707751.html . 23 December 2010 . 10 August 2019.
  25. Web site: Instructions for the Conversions of Areas to Metric. Law Society of South Africa. November 2007. 27 December 2013. 20 March 2018. https://web.archive.org/web/20180320105433/https://www.lawsoc.co.za/webs/surveyorgeneral/2007_11_area_conversion.doc.
  26. Book: O'Callaghan, Edmund Bailey . Laws and Ordinances of New Netherland, 1638–1674. 1868. Weed, Parsons, printers. Albany, NY. 335.
  27. Web site: RootsWeb.com Home Page. www.rootsweb.ancestry.com. 1 May 2018. https://web.archive.org/web/20180501133050/http://www.rootsweb.ancestry.com/~nycoloni/nnlandex.html,. 1 May 2018.
  28. News: Why is Wales used as a unit of measurement? . BBC News . 22 January 2019. 22 January 2019 . Frampton . Ben .
  29. News: Expat joins Falklands council. 24 December 2005. news.bbc.co.uk.
  30. News: Diary: The Amazon rainforest. 19 July 2006. news.bbc.co.uk.
  31. Web site: Haines. Lester. So, what's the velocity of a sheep in a vacuum?. https://web.archive.org/web/20131114110120/https://www.theregister.co.uk/2007/08/24/vulture_central_standards/?page=2. 14 November 2013. The Register. 24 August 2007. 25 August 2015.
  32. Web site: What next for Size of Wales?. Size of Wales. 31 May 2014.
  33. News: Vaughn. Adam. Welsh charity saves an area of rainforest the size of Wales. 31 May 2014. Guardian. 1 March 2013.
  34. Web site: Area - comparative - The World Factbook . 2024-03-14 . www.cia.gov.
  35. News: Chris . Edwards . Quizzical: this month, Chris Edwards tackles temperature extremes, the size of Belgium, categorising nations' development status, the hydrogen bombs dropped on Japan and the number of people who speak Scottish Gaelic . . August 2005 . 20 May 2009 . https://web.archive.org/web/20110413081725/http://findarticles.com/p/articles/mi_hb3120/is_8_77/ai_n29198390/ . 13 April 2011 .
  36. Web site: White . Jamie . Would The World's Population Fit on the Isle of Wight? . . 8 March 2018 .
  37. News: Größenordnungen: Das Saarland – das Vergleichsmaß vieler Dinge – DIE WELT. Marco Krefting. 18 February 2010. DIE WELT.
  38. Web site: Food and Drugs: FDA Food Labeling . 1 April 2004 . . 27 August 2012 . https://web.archive.org/web/20120204081321/http://edocket.access.gpo.gov/cfr_2004/aprqtr/21cfr101.9.htm . 4 February 2012 .
    For Nutrition facts labeling "a teaspoon means 5 milliliters (ml), a tablespoon means 15 ml, a cup means 240 ml, 1 fl oz means 30 ml, and 1 oz in weight means 28 g".
  39. Web site: Practical information. Holland Expat Center.
  40. Book: Encyclopaedia Britannica Almanac 2009. 2009. Encyclopædia Britannica. 978-1-59339-839-2. 160. Encyclopædia Britannica Inc. Staff . 22 April 2013.
  41. Web site: what is one pony . Wolfram Alpha . 19 June 2014 . 19 June 2014.
  42. Web site: Weights and measures: the law. GOV.UK.
  43. Book: Husch, Bertram . Thomas W. Beers . John A. Kershaw . Forest Mensuration . John Wiley and Sons . 2003 . 978-0-471-01850-6.
  44. Web site: British Columbia Ministry of Forests and Range. Glossary of Forestry Terms in British Columbia. 4 September 2008.
  45. Web site: Units: R. Rowlett. Russ. 25 April 2002. How Many? A Dictionary of Units of Measurement. 10 August 2019.
  46. Web site: NM OSE Glossary. https://web.archive.org/web/20051114202301/http://www.ose.state.nm.us/water_info_glossary.html. 14 November 2005. 15 March 2014.
  47. Book: Sewers: Repair and Renovation. Butterworth-Heinemann . Geoffrey F Read . Ian Vickridge . 24 December 1996. 29 June 2016. 978-0-08-054112-9.
  48. Paul Hudson: 3rd anniversary of June 2007 floods, showing a storm water storage tank "half the size of an Olympic swimming pool"
  49. Web site: SI Units – Volume. Isabel. Chavez. 1 August 2011. nist.gov. 1 May 2018.
  50. p "Landfill tax 'costing homes £30'", BBC News website
  51. Web site: A Day in the Life – An Indepth Analysis – The Origins of the Song . 18 September 2010 . https://web.archive.org/web/20080419020720/http://www.applecorp.com/aditl/origins.htm . 19 April 2008.
  52. Book: Atwood, Robert . 2006. Bears Can't Run Downhill, and 200 Dubious Pub Facts Explained. Ebury Press. 124. 978-0-09-191255-0.
  53. Web site: Trouble brewing at the bottom of the bay . The Age . 4 September 2014. 6 December 2003 .
  54. Web site: How big is the MCG? Surveyors find exact measurements of Melbourne Cricket Ground. Australian Broadcasting Corporation. Margaret Paul. 20 August 2015. 20 August 2015.
  55. Web site: The secret harbour uncovered. https://web.archive.org/web/20160116134156/http://www.smh.com.au/news/National/The-secret-harbour-uncovered/2004/12/10/1102625541209.html. 16 January 2016. 11 December 2004.
  56. Web site: When dam size matters . Australian Bureau of Meteorology . 4 September 2014.
  57. Web site: NSW Irrigators' Council (NSWIC). Useful Water Comparisons. 4 September 2014. 4 March 2016. https://web.archive.org/web/20160304091232/http://www.nswic.org.au/pdf/fact_sheets/USEFUL%20WATER%20COMPARISONS.pdf. dead.
  58. News: Scientists find missing link in Yellowstone plumbing: This giant volcano is very much alive. Joel Achenbach. 23 April 2015. Washington Post.
  59. How Many Things Are There?. https://ghostarchive.org/varchive/youtube/20211117/C6eOcd06kdk. 17 November 2021 . live. 28 April 2014. YouTube.
  60. Web site: Human Cube – eesmyal. 24 April 2015. 18 April 2015. https://web.archive.org/web/20150418141341/http://eesmyal.com/2012/02/human-cube/. dead.
  61. Web site: Park Statistics - Grand Canyon National Park (U.S. National Park Service). www.nps.gov.
  62. Web site: Frequently Asked Questions, unit weights. Portland Cement Association. 2011. 15 February 2011.
  63. News: Out There: A Strange Zoo of Other Worlds . Space.com . 14 February 2010.
  64. Book: George Gamow. One Two Three ... Infinity: Facts and Speculations of Science. New York. Viking. 1947. 77. One Two Three ... Infinity.
  65. [N. David Mermin]
  66. Web site: The Pathogenesis and Therapy of Combined Radiation Injury . https://web.archive.org/web/20070106134035/http://www.afrri.usuhs.mil/www/outreach/pdf/CR06_1.pdf . 6 January 2007 . Defense Threat Reduction Agency . 12 November 2006 .
  67. Web site: microfortnight. catb.org.
  68. Web site: OpenVMS Frequently Asked Questions (FAQ), Part 3/11 . 4.1.1.1.4 EXE$GL_TODR . 11 April 2005 . 10 March 2009.
  69. See, for instance, the current Mean Julian Day, precise to 6 decimal place, from the United States Naval Observatory.
  70. Web site: Watchmaker With Time to Lose . JPL Mars Exploration Rovers . 2014 . 22 January 2015.
  71. Web site: After Finding Mars Was Habitable, Curiosity Keeps Roving . Nola Taylor . Redd . space.com . 18 March 2013 . 22 January 2015.
  72. https://web.archive.org/web/20110612143355/http://today.msnbc.msn.com/id/43339983/ns/today-today_pets_and_animals Multimillionaire pooch dies at age 12 (84 in dog years)
  73. Web site: Dog-Food-Corner.com . https://web.archive.org/web/20131214005631/http://www.dog-food-corner.com/dog-years-human-years-age.htm . 14 December 2013.
  74. Web site: Sexual Maturity — Spay and Neuter. https://web.archive.org/web/20090610035254/http://www.pets911.com/hosted/buffalo/puppy/article.php?num=11045. 10 June 2009. Buffalo.com. 22 October 2008.
  75. Web site: Geologic Time Galactic . vendian.org . 19 December 2006.
  76. Web site: KerMetric Time Display Calculator. www.csgnetwork.com.
  77. Herschel . William . 186209747 . 1785 . Catalogue of Double Stars . . 75 . 40–126 . 106749 . 10.1098/rstl.1785.0006 .
  78. Furman . Alan T. . The Cordic Algorithm for Fixed-Point Polar Geometry . FORTH Dimensions . 4 . 14–15 . 16 January 2009 .
  79. Book: Collins Concise Dictionary of the English Language. 1982. Collins . 978-0-00-433091-4. William T. Macleod.
  80. Book: Brown, Russel H. Inertial Instrument System for Aerial Surveying. U.S. Geological Survey Professional Paper. 1390. 1987. U.S. Government Printing Office. 14.
  81. Web site: USEFUL CONSTANTS. Hpiers.obspm.fr. 22 September 2018.
  82. Web site: Environmental Protection Agency Fuel Economy Label – Final Report . https://web.archive.org/web/20110213112025/http://www.epa.gov/fueleconomy/label/420r10909.pdf . 13 February 2011 . US Environmental Protection Agency. September 2010. 20 February 2011.
  83. Book: Time: Disasters that Shook the World. Time Home Entertainment. New York City. 2012. 56. 978-1-60320-247-3.
  84. Basic Choices and Constraints on Long-Term Energy Supplies. July 2004 . Physics Today. 57. 7. 47–52. 10.1063/1.1784302. Weisz. Paul B.. 2004PhT....57g..47W. free.
  85. Web site: Amazon River – Facts, History, Animals, & Map . Encyclopedia Britannica . 10 August 2019. .
  86. Fundamentals of High Accuracy Inertial Navigation, Averil B. Chatfield, [American Institute of Aeronautics and Astronautics], 1997, p.32
  87. 10.1016/j.chroma.2013.01.038. 23398992. A re-investigation of the Mark–Houwink–Sakurada parameters for cellulose in Cuen: A study based on size-exclusion chromatography combined with multi-angle light scattering and viscometry. Journal of Chromatography A. 1281. 32–37. 2013. Kes. Mürşide. Christensen. Bjørn E..
  88. Web site: Ahora la borrachera es "previa" a la fiesta . elpais.com.uy . 15 October 2009 . https://web.archive.org/web/20091015002051/http://www.elpais.com.uy/091011/pciuda-447246/ciudades/ahora-la-borrachera-es-previa-a-la-fiesta . 15 October 2009 . es . 10 August 2019.
  89. Web site: The unemployed would fill three and a half Centennial Stadiums (Spanish) . LARED21 . 7 November 2002 . es . 10 August 2019.
  90. Web site: 2017-03-14 . By 2018, Enough Americans Will Lose Health Insurance To Fill Michigan Stadium 130 Times . 2024-03-14 . HuffPost . en.
  91. Web site: Diabetes Australia. Diabetes – The Facts. 4 September 2014. 13 October 2014. https://web.archive.org/web/20141013221559/http://www.diabetesaustralia.com.au/PageFiles/1615/the%20facts%20DA%20FINAL%202011.pdf. dead.
  92. Web site: NSW Department of Education and Communities. What the experts say about cyberbullying. 4 September 2014. 4 September 2014. https://web.archive.org/web/20140904132206/http://www.schoolatoz.nsw.edu.au/technology/cyberbullying/what-the-experts-say. dead.
  93. Web site: The Age. Trouble brewing at the bottom of the bay. 4 September 2014.
  94. Book: The Bible, Old and New Testaments, King James Version – Project Gutenberg. 7 December 2011.
  95. News: 44 Million Words Strong, Britannica to Join Internet. John Markoff. 7 December 2011. 8 February 1994. The New York Times.
  96. Web site: How Much Information?. Peter Lyman. Hal R. Varian. 29 November 2011. 18 October 2000. 16 August 2011. https://web.archive.org/web/20110816181442/http://www2.sims.berkeley.edu/research/projects/how-much-info/how-much-info.pdf#page=110. dead.
  97. Web site: TOP500 LIST November 2018 . Top 500 . 21 January 2019.
  98. Web site: Triumph of the Nerds: The Transcripts, Part II . PBS . 10 August 2019.
  99. Web site: April 2017 – "How many WaPs is that?" . Pegasus Mail and Mercury . 30 November 2011 . 10 August 2019.
  100. Book: Laplante . Phillip A. . Ovaska . Seppo J. . Real-Time Systems Design and Analysis: Tools for the Practitioner . 22 November 2011 . John Wiley & Sons . 978-0-470-76864-8 . 122 . en.
  101. Book: Bovet . Daniel P. . Cesati . Marco . Understanding the Linux Kernel: From I/O Ports to Process Management . 17 November 2005 . O'Reilly Media, Inc. . 978-0-596-55491-0 . 245 . en.
  102. Web site: Chess Play Quality Index . chess-db.com . 1 May 2018 . https://web.archive.org/web/20161211211029/http://chess-db.com/public/research/qualityofplay.html . 11 December 2016 .
  103. Web site: Robert E. Stevenson Oral History . NASA – Johnson Space Center History . 13 May 1999 . 10 August 2019.
  104. Country Gentleman. v.75 1910. . Better Farming1955 . 2 January 2019 . 2027/mdp.39015043511578 .
  105. Web site: The Truth About Availability: What does 99.99% mean?. c0nnexx10n: C0nnect1ng L1fe w1th Techn010gy. 24 October 2008.
  106. Book: McGachie. Richard O. . Bradley. Anne Grace . Precious metals. 4. 1981. Pergamon. 978-0-08-025369-5. 262.
  107. Book: PVD for Microelectronics: Sputter Desposition to Semiconductor Manufacturing. 1998. 387.
  108. Book: Tainter, Donna R.. Anthony T. Grenis . 2001 . Spices and Seasonings . Wiley-IEEE . 978-0-471-35575-5 . 30. — "Interlab variation [for the original Scoville scale] could be as high as ±50%. However, labs that run these procedures could generate reasonably repeatable results."
  109. Web site: How Hot is That Pepper? How Scientists Measure Spiciness . www.smithsonianmag.com . 20 June 2016.
  110. William B. Jensen . Jensen . William B. . September 2004 . The Origin of Alcohol 'Proof' . Journal of Chemical Education . 10.1021/ed081p1258 . 81 . 9 . 1258–1259 . 2004JChEd..81.1258J . 17 July 2014 . https://web.archive.org/web/20140708232531/http://www.che.uc.edu/jensen/W.%20B.%20Jensen/Reprints/111.%20Proof.pdf . 8 July 2014.