List of unusual units of measurement
From Wikipedia, the free encyclopedia
Strange and whimsical units are sometimes used by scientists, especially physicists and mathematicians, and other technically-minded people such as engineers and programmers, as bits of dry humor combined with putative practical convenience. See also List of humorous units of measurement. For units that are primarily used in non-English-speaking countries, please see the article on units specific to that country.
[edit] Systems of measurement
Most units of measurement are collected into various standards, such as the SI units (sometimes called the metre-kilogram-second system), the Imperial system (sometimes called the foot-pound-second system), as well as various older standards used in countries throughout the world. Some of these standards are strange in their own right.
[edit] MTS units
During the twentieth century, the Soviets and French briefly used a variant of the metric system where the base unit of mass was the tonne. This meant that a kilogram was a millitonne (mt). Conversely, some companies are using the megagram (Mg), to avoid confusion with long or short tons.
- See also: Mesures usuelles
[edit] FFF units
Most countries use the International System of Units (SI). In contrast, the Furlong/Firkin/Fortnight (FFF) system of units of measurement draws its attention by being conservative and off-beat at the same time.
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| furlong | length | 1/8 of a mile | 201.168 m |
| firkin | mass | 9 Imperial gallons of water | 40.91481 kg |
| fortnight | time | 14 days | 1,209,600 s |
One furlong per fortnight is very nearly 1 centimetre per minute (to within 1 part in 400). Indeed, if the inch were defined as 2.54 cm rather than 2.54 cm exactly, it would be 1 cm/min. Besides having the meaning of "any obscure unit", furlongs per fortnight have also served frequently in the classroom as an example on how to reduce a unit's fraction. The speed of light may be expressed as being roughly 1.8 terafurlongs per fortnight.[1][2]
[edit] SI-imperial hybrids
In the U.S., new mongrel units are sometimes formed by a combination of traditional units, still widely used, and metric units. Thus, "grams per fluid ounce" is a common unit used in sports nutrition, for example to express the concentration of carbohydrate in a beverage.
A hybrid standard quantity used in mining is the assay ton (AT), which is as many milligrams as there are Troy ounces in an avoirdupois long ton. So to find how many ounces of gold are in a ton of rock, one measures the number of milligrams of gold in an assay ton of rock.
There are also reports of engineers realizing the comfort of base ten SI prefixes, combining them with Imperial or U.S. customary units instead of making the full switch, for example the kiloyard (914.4 m). The kip or kilopound is regularly used in structural engineering. Similarly, the kilofoot is quite common in U.S. telecommunication engineering, as significant distances in cable route planning are usually given in thousands of feet. Instruments like optical time domain reflectometers usually have an option to display results in kft.
[edit] Derived units
There are some obscure metric units: with arbitrary units and prefixes, you can express a common unit with an unfamiliar term. Among physicists there is the in-joke replacing common units with uncommon units, as in velocity: metres per second = hertz per dioptre (Hz/dpt). In this case, the reciprocal values of metre and second — dioptre and hertz, respectively — are used to contrive the same unit.
[edit] Length
[edit] Length: attoparsec
Parsecs are used in astronomy to measure enormous interstellar distances. A parsec is approximately 3.26 light-years or about 3.085×1016 m. Combining it with the "atto" prefix yields attoparsec, a conveniently human-scaled unit of about 3.085 centimeters (about 1 7/32 inches) that has no obvious practical use but does have a proper SI symbol, apc.
Interestingly, 1 attoparsec/microfortnight is nearly 1 inch/second (the actual figure is about 1.0043 inches per second, or approximately 2.55 cm/s). See mathematical coincidences for a list of similar factoids. [2]
[edit] Length: light-nanosecond
Beyond its more traditional use as a unit of time, the nanosecond (or light-nanosecond) was popularized 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." In her speaking engagements, she was well-known for passing out light-nanoseconds of wire to the audience, and contrasting it with light-microseconds (a coil of wire 1000 times as long) and light-picoseconds (ground black pepper). Over the course of her life, she had many motivations for this visual aid: including demonstrating the waste of sub-optimal programming, illustrating advances in computer speed, and simply giving young scientists and policy makers the ability to conceptualize the magnitude of very large and small numbers.[3]
[edit] Length: metric inch
The international inch is defined to be exactly 25.4 mm. However, this is approximated to 25 mm, to give a "metric inch".
A metric inch was used in some Soviet computers when building from (stolen) American blueprints. The resulting products would seem like their American models but components were not interchangeable.
[edit] Length: State of Kansas
Meteorologists in the United States use the state of Kansas, which spans 3 degrees of latitude, as a distance scale on weather maps of the contiguous United States. One nautical mile used to be defined as exactly 1 minute of arc on the Earth's surface[citation needed], and since there are 60 minutes to a degree, it can be seen that Kansas is 180 nautical miles from North to South. Since meteorologists typically measure wind speed in knots (nautical miles per hour) the use of nautical miles in measuring distances is convenient. Also, the lack of a printed distance scale makes room for other keys, such as color codes and date information[citation needed]
[edit] Length: storeys (stories)
All buildings are made up of storeys (UK and Commonwealth) or stories (U.S.), also referred to as floors or levels. In the United States, each story is generally 8 to 10 feet (2.4 to 3 meters). The number of stories is used to express the height of a building or nonbuilding structure.
In Brazil, the stories are used mainly by the media as a proxy for 3 meters. It's normally employed in situations to express heights of buildings or elevations.
[edit] Length: double-decker bus
In Britain, newspapers and other media will frequently refer to heights in comparison to the length (8.4 metres) or height (4.4 metres) of a London Routemaster double-decker bus. [3]
[edit] Length: football field
In the United States, this refers to the length of an American football field, which has a playing area 100 yards (91.44 meters) long. This is often used by the American public media for the sizes of large buildings or parks: easily walkable but non-trivial distances. British media also frequently uses the football pitch for equivalent purposes, although Association Football (Soccer) pitches are not of a fixed size, but instead can vary within defined limits (100-130 yards long, and 50-100 yards wide, giving an area of 5000 to 13,000 yards2).
[edit] Length: block
A city block (in most U.S. cities) is between 1/8 and 1/16 mi (0.2 and 0.4 km). In Manhattan, the measurement "block" usually refers to a north-south block, which is 1/20 mi (0.08 km). Within a typical large North American city, it is often possible to travel along only 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 distance).
[edit] Length: tall buildings
In the UK, Nelson's Column and Blackpool Tower (61.5 m and 158 m respectively) are commonly used by British newspapers or reference books to give the comparative heights of buildings or, occasionally, mountains.
In the USA, buildings such as the Empire State Building (449 m), Sears Tower (519 m), and Seattle Space Needle (184 m) are used as comparative measurements of height, as are the Statue of Liberty and Washington Monument. The Empire State Building (but not the others mentioned) is also used in Britain for describing particularly large/tall objects, where Nelson's Column or the Blackpool Tower would not seem impressive enough.
In Canada (and occasionally elsewhere), the Toronto CN Tower (553 m) is used in a similar fashion. In Western Canada, the Calgary Tower is often used as a comparison.[4][5][6]
- See also: World's tallest structures
[edit] Length: farsee
Used primarily in rural areas, like the Appalachian region of the United States, while giving directions. It is roughly defined to be as far as one can see. For example, a person could travel two farsees by noting the top of a hill on the horizon, walking to that spot, and then noting the top of the next hill in the same direction, which would mark his destination. A variation of the word farsee that is understood to carry less prestige is farsaw, as well as the term seefar, though that's just a reversal.[citation needed]
[edit] Length: siriometer
The siriometer is a rarely used astronomical measure equal to one million astronomical units, i.e., one million times the average distance between the Sun and Earth. This distance is equal to about 15.8 light-years, about twice the distance from Earth to the star Sirius.
[edit] Area
[edit] Area: nanoacre
A nanoacre is a unit (about 4 mm²; ≈ 2.01168 mm wide, ≈ 2.01168 mm long) of real estate on a VLSI chip. "The term gets its humor from the fact that VLSI nanoacres have costs in the same range as real acres in Silicon Valley once one figures in design and fabrication-setup costs."[4]
[edit] Area: football field
In many countries, a football pitch (or football/soccer field) is used as a man-in-the-street unit of area.[7][8] It is necessarily restricted to order-of-magnitude comparisons by the fact that football pitches are officially allowed to vary by a factor of 2.67 in area (between 4,050 and 10,800 m², i.e. roughly 0.5 to 1 hectare) although this factor drops to 2.01 in the case of pitches approved for international matches.
[edit] Area: Belgium/Wales/Isle of Wight/Rhode Island/Texas/Alaska/Washington D.C.
The area of a familiar country, state or city is often used as a unit of measure, especially in journalism.
Conservationists discussing the destruction of the Amazon Rainforest often use Belgium as an approximate measure of how much forest is being lost annually. The area of Belgium is 30,528 km². In the United Kingdom, Wales, equal to 20,779 km², is used in phrases such as "an area the size of Wales" or "twice the area of Wales".[9][10] The Isle of Wight (380 km²) is commonly used for smaller areas.
In the United States, the areas of Rhode Island (1,545 sq mi), Texas (268,601 sq mi, commonly used due to its historic "larger than life" reputation), and rarely Alaska (656,425 sq mi) are used in a similar fashion. Antarctica's Larsen B ice shelf was approximately the size of Rhode Island until it broke up in 2002. Due to the Rhode Island being a relatively small unit of measurement (and, perhaps, due to its area being 33% water), many comparisons to the size of Rhode Island are somewhat imprecise.[5] The U.S. Central Intelligence Agency uses Washington, D.C. as a comparison for city-sized objects.
In Finland, the region of Uusimaa (6,366 km²) is conveniently sized for area comparisons.
- See also: The size of Wales
[edit] Cubic Volume
[edit] Cubic Volume: board foot
A board foot is an old American unit of volume, used for wood. It is equivalent to 1 inch × 1 foot × 1 foot, or 144 cubic inches. However, in practice, it is defined differently for hardwood and softwood. It is also found in the unit of density pounds per board foot.
[edit] Cubic Volume: stère
The stère (st) is equal to a cubic metre (m³), or kilolitre (kl). The stère is traditionally used to measure a quantity of wood.
[edit] Cubic Volume: Olympic-sized swimming pool
For smaller volumes of liquid, one measure commonly used in the media in many countries is the Olympic-sized Swimming Pool. A large Olympic swimming pool with dimensions 50m x 25m x 2m holds 2,500,000 litres, that is, 1/200,000 of a sydharb.
[edit] Cubic Volume: sydharb
A unit of volume used in Australia for water. One sydharb is the amount of water in Sydney Harbour: approximately 500 gigalitres.[6]
[edit] Mass
[edit] Mass: grave
In 1793, the French term "grave" (from "gravity") was suggested as the base unit of mass for the metric system. In 1795, however, due in no small part to the French Revolution, the name "kilogram" was adopted instead.[7]
[edit] Time
[edit] Time: shake
In nuclear engineering and astrophysics contexts, the shake (from "two shakes of a lamb's tail") is used as a conveniently short period of time. 1 shake = 10 nanoseconds.[8]
[edit] Time: nanocentury
Another derived time unit, reducing a rather large time span (century) by preceding it with a fractional prefix (nano). As Tom Duff at Bell Labs pointed out: "How many seconds are there in a year? If I tell you there are 3.156×107, you won't even try to remember it. On the other hand, who could forget that, to within half a percent, π seconds is a nanocentury."
One computer science professor used to characterize the standard length of his lectures (a little less than an hour) as a microcentury. (roughly 52.6 minutes, accounting for leap years).[citation needed]
[edit] Time: 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 1/60 of a second, roughly equal to the vertical blanking interval on NTSC video hardware (and the frequency of AC electric power in North America).
[edit] Time: microfortnight
One very convenient unit deduced from the FFF system is the millionth part of the fundamental timeunit of FFF, which equals 1.2096 seconds, and is a typical example of computer nerd humour[11]. As the story goes, "The VMS operating system has a lot of tuning parameters that you can set with the SYSGEN utility, and one of these is TIMEPROMPTWAIT, the time the system will wait for an operator to set the correct date and time at boot if it realizes that the current value is bogus. This time is specified in microfortnights."
The joke is in having a rather large unit (fortnight) combined with a fractional SI prefix (micro) to counteract that. The practical purpose is to discourage setting such parameters without some thought. The unit was selected because the time is only approximately one second, being established by some near-infinite loops rather than a real clock unit (which isn't active at the time), and rather than field complaints about this being "not exactly a second", the unit was invented.
[edit] Time: galactic year
The most common large-scale time scale is millions of years (MY). However, for long-term measurements, this still requires rather large numbers. Using as a measure the time it takes for the solar system to revolve once around the galactic core (GY), approximately 250 MY, yields some easily memorizable numbers. In this scale, oceans appeared after 4 GY, life began at 5 GY, and multicellular organisms first appeared at 15 GY. Dinosaurs went extinct about 0.4 GY ago, and the true age of mammals began about 0.2 GY ago. The age of the Earth is estimated at about 20 GY.[9]
- See also: galactic year
[edit] Other conventional scales
[edit] Energy: jerk
In very high energy physics, particularly in the nuclear weapons and astrophysics communities,[10] the jerk is used as a conveniently large quantity of energy. 1 jerk = 1016 ergs = 109 joules = 1 gigajoule. This unit jerk is different from, and must not be confused with, the vector quantity jerk, which is defined as the first derivative of acceleration with respect to time.
[edit] Energy: foe
A foe is a unit of energy equal to 1044 joules that was coined by physicist Gerry Brown of SUNY-Stony Brook. 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] fifty-one ergs, or 1051 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).
[edit] Energy intensity: langley
The langley (symbol Ly) is used to measure solar radiation or insolation. It is equal to one thermochemical calorie per square centimetre (4.184×104 J/m²) and was named after Samuel Pierpont Langley.
[edit] Kinematic viscosity: stokes
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, ie. 10-4 m²/s.
[edit] Electromagnetic flux: jansky
In radio astronomy, the unit of electromagnetic flux is the jansky (symbol Jy), equivalent to 10−26 watts per square metre per hertz (in base units 1 kg·s-4). 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.
[edit] Money
[edit] Money: cup of coffee
In Italy, the cost of an espresso is often used as a unit with which to measure a price in order to make it appear small: e.g., "For less than the cost of a cup of coffee a day, you can...". This usage has become less common due to rising prices at bars; however, it remains especially popular with charity organizations asking for donations. Other common units are the cost of a pizza and that of a can of Coca-Cola.
In Denmark, charity organizations such as WWF and Unicef sell subscription memberships by advertising that it's "less than the cost of a pizza a month".
In the United States, the price of a cup of coffee is often used by various world relief fund organizations, e.g. "For less than the cost of a cup of coffee per day, you can feed a hungry orphan in (insert country here)" (again, Coke is also used).
In Greece coffee has been used along with water or a soda drink as monetary unit. When consumers started complaining about the rising prices of gasoline petrol station owners would point out that it cost less than water (about € 1 per liter in kiosks). Soda drinks have been used for comparison — e.g., "For less than the cost of a soda drink per day, you can have a (satellite TV, aircondition etc) in your home". Coffee is less popular because at € 3-4 per cup it is seen as expensive.
[edit] Money: pint of beer
In the UK, the 'pint' (of beer) is used to denote trivial sums that are slightly too large to be forgotten about. Depending on the establishment, location and brand, a pint of beer in a reasonably-priced English pub costs between about £2 and £3. The unit is used (in a financial setting) mainly due to the repaying of trivial debts between friends via alcoholic purchase.[citation needed]
[edit] Money: case of beer
In the United States, a case is the common name used to refer to a 24-pack of beer. A case of cheap beer, such as Natural Light or Keystone Light, generally costs around 10 U.S. dollars (€ 8.2). Seeing how beer is a staple among college students, it is understandable that the term "case" is used. For example, a college student might say, "My tuition this year cost me 1000 cases!"[citation needed] In Australia, this unit is refered to as a slab of beer and is widely used in some rural areas.[11][12]
[edit] Units for unconventional measurements
Formal scientific measurements of abstract quantities such as 'Beauty', 'Happiness' and 'Comfort' are sadly lacking and many humorists have stepped in to fill the void.
[edit] Uncertainty: microbit
The Finnish computer magazine MikroBitti once claimed to be named after the microbit, defined as one millionth of a bit. In the usual sense of a bit as a discrete entity being either 0 or 1, a fractional bit is not conceptually sound. However, in the sense of information entropy, a bit is a measure of uncertainty. Thus, although this term is never used in practice, a microbit indicates a very small amount of uncertainty. For example, the amount of information corresponding to the knowledge of whether a given second in the 1990s is a leap second is about 0.4 microbits.[citation needed]
[edit] Original content for publication: pub-on
Part unit of measure and part entity-in-itself, the pub-on is the quantum of material submitted to a peer-reviewed journal for publication. Manuscripts barely containing enough new information to qualify as 'original research' are said to consist of a single pub-on, while far-reaching works with many new and interesting results and interpretations might contain many. Publishing papers consisting of only a few pub-ons may make an author's catalogue of papers longer, but will tend to swamp editor's desks and confound the system for other authors.[citation needed] This quantity is also commonly referred to as a least publishable unit (LPU) or "publicon"
[edit] Fame: warhol
This is a unit of fame or hype, derived from Andy Warhol's dictum "everyone will be world-famous for fifteen minutes" —it represents, naturally, fifteen minutes of fame. Some multiples are:
- 1 kilowarhol — famous for 15,000 minutes, or 10.42 days. A sort of metric "nine day wonder".
- 1 megawarhol — famous for 15 million minutes, or 28.5 years. The type of person your parents talk about all the time, but of whom you've never heard from anyone else.
First used by Cullen Murphy in 1997.[13]
Also used simply as meaning 15 minutes; as the Warhol worm, that could infect all vulnerable machines on the entire Internet in 15 minutes or less.
[edit] Bleeding: The Muta Scale
Used to describe how much a professional wrestler bleeds during a match, compared to a New Japan Pro Wrestling match between The Great Muta and Hiroshi Hase on December 14, 1992 in which Muta bled in amounts previously unheard of.[citation needed]
The Muta is normally measured in tenths, ranging from 0.1 Muta to 1.0 Muta, 1.0 Muta is also known as a "Full Muta. Cactus Jack is usually said to have reached 1.0 Muta in the finals of the 1995 IWA King of the Deathmatch tournament, while more recently, The Undertaker is thought to have reached 1.0 Muta in his match at the 2002 No Mercy against Brock Lesner in the Hell in a Cell main event match (An angle was quickly created to give The Undertaker an alibi to leave the ring to recouparate, this took three months).
The Muta Scale can be used to measure either legitimate blood-loss (known in wrestling slang as "juicing hardway") or that produced by a self-inflicted wound, usually to the forehead by means of a razor.
[edit] Data storage capacities: encyclopedias, Bibles and The Library of Congress
When the compact disc began to be used as a data storage device, the CD-ROM, journalists had to compare the disc capacity (650 MB) to something everyone could imagine. Since many Western households have at least one Christian Bible, and the Bible is a comparatively long book, it was often chosen for this purpose. The King James Version of the Bible in uncompressed plain 8-bit text contains about 4.5 million characters,[14] so a CD-ROM can store about 130 Bibles.
The Encyclopædia Britannica is another common data size metric - it contains approximately 300 million characters, so two copies would fit comfortably onto a CD-ROM.[citation needed]
The term Library of Congress is sometimes used as a unit of measurement when discussing large amounts of data. It refers to the U.S. Library of Congress. One Library of Congress equals approximately 20 tebibytes of uncompressed textual data.[citation needed]
In most cases, diagrams and photographs are not included in the total – since these take considerably more space than text, this would be an important consideration for practical storage of large book collections. In practice, diagrams can often be expressed more compactly using vector graphics, and data compression software can pack more text into the available space. It is possible to compress English text to about 11% of its original size. Thus one might claim that the entire Library of Congress could be packed onto a single 2.2 terabyte storage unit - excluding the pictures.
- See also: Wikipedia:Size comparisons
[edit] Bandwidth: station wagon full of mag-tape
An observation made in the early days of Usenet that the highest bandwidth method of moving networknews across the country was "a station wagon full of mag-tape". The phrase is attributed to many people, including Karl Kleinpaste and Andrew Tanenbaum, and has been subject to countless variations of vehicle and media types (eg "a 747 full of DVDs" or "an intern with a box full of floppies").
As a measurement unit, this is used more as a method of comparison between network technologies than as an actual hard measurement of bandwidth. It also depends crucially on the distance of the communication, e.g. "An ethernet has more bandwidth than an intern with a cartload of CDs" is certainly true over large distances - but is unlikely to be the case for short range communication. This measure also overlooks any latency involved in transferring data between the transport medium and on-line storage, which may be considerable for tape.
- See also: Sneakernet
[edit] Laser power: Gillette
A unit described by Theodore Maiman as an early measure of laser output power. The measure was simply the number of razor blades through which the laser could burn a hole. This measurement was especially convenient as the first lasers were pulsed ruby lasers, making it otherwise difficult to measure the output power. Also, due to the relative uniformity of razor blades manufactured by The Gillette Company, it had some usefulness as a rough comparison.[citation needed]
Thus, scientists would brag about having a "4 Gillette" laser versus their competitor's puny "2 Gillette" laser. (For the record, Ted Maiman claims that the first laser was a "2 Gillette" laser.)
[edit] Quantity of alcohol: unit of alcohol
In the UK, units of alcohol are used in the health industry and some government campaigns to measure the amount of alcohol consumed. One unit is believed to be approximately 10 cc of ethanol, or about 8 grams. The recommended weekly intake is no more than 14 units for women, and 21 units for men.[15][16]
- See also: standard drink
[edit] Scalar: sagan
A whimsical unit of measure equaling at least 4,000,000,000. Based on the quote "billions of stars" used by Carl Sagan and popularized with the derivation "billions and billions of stars" by Johnny Carson.
[edit] Purchasing power parity: Big Mac index
The Economist's Big Mac index compares the purchasing power parity of countries in terms of the cost a Big Mac hamburger.[17]
[edit] Purchasing power parity: iPod index
![Apple iPod nano prices - Sydney Morning Herald [1]](../../../upload/thumb/c/c5/IPodgra.jpg/150px-IPodgra.jpg)
A successor to the Big Mac index, the iPod index compares a country's purchasing power parity in terms of the relative cost of an 2GB Apple iPod nano (Second Generation) in US Dollars. The iPod Index is considered to be more accurate than the Big Mac index for several reasons. While the make-up of a Big Mac is more-or-less constant world wide, its cost is dependent on the local cost of both ingredients and labour, as well as varying local demand (For instance, demand for Big Macs in India is lower than comparable countries due to the large Hindu population). Conversely, all iPod nanos are manufactured in the same place (China) from the same materials, and their prices are not dictated by demand. While this raises issues with regard to shipping costs, given the ratio of physical size to retail price of a single iPod nano unit, the effect of shipping-cost-per-unit is negligible.[citation needed]
[edit] 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.[18]
[edit] Computer program length: KLOC
A computer programming expression, the KLOC, pronounced kay-lok, standing for "Kilo-Lines of Code", i.e. "Thousand Lines of Code". The unit is used, especially by IBM managers, to express the amount of work required to develop a piece of software. Given that estimates of 20 lines of functional bug-free code per day per programmer were often used, it is apparent that 1 KLOC could take one programmer as long as 50 working days, or 10 working weeks.
[edit] Mache Unit
The Mache Unit, symbol ME (from the German "Mache-Einheit"), is a unit of activity used to gauge mineral springs. It is defined as the quantity of radon per litre which delivers one millionth of a röntgen (that is to say, ionises a sustained current of one StatAmpere, or 10−3 esu). This works out to about 1.3468 × 104 Bq/m³ (or 0.364 nCi/L).
[edit] Morgan
The morgan is a rarely-used unit related to the distance between genes on a chromosome. Only a daughter unit, the centimorgan, is commonly used. In humans, the morgan would be approximately 100 million base pairs long.[citation needed]
[edit] Nibble
A measure of quantity of data or information, the "nibble" (sometimes spelled "nybble") is 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 packed decimal format, or to represent a single hexadecimal digit (see nibble).[citation needed]
[edit] Nines
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%.[citation needed]
Typical areas of usage are:
- the reliability of computer systems, that is the ratio of uptime to the sum of uptime and downtime. "Five nines" reliability in a continuously operated system means an average downtime of no more than approximately five minutes per year.
- the purity of materials, such as gases and metals.
[edit] Alcohol concentration: proof
Up to the 20th century, alcoholic spirits were assessed in the UK by mixing with gunpowder and testing the mixture to see if 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 at 20°C, where spirit at 100° proof is approximately 57.15% ABV; the U.S. uses a proof number of twice the ABV at 60°F (15.5°C).[citation needed]
[edit] Audible frequency ratio: savart
An 18th century unit for measuring the frequency ratio of two sounds, it is equal to 1/300 of an octave, or 1/25 of a semitone. Still used in some programs, but considered too rough for most purposes. Cent is preferred.
[edit] Pepper hotness: 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'. Pure capsaicin (the chemical responsible for the 'heat') has 1.6 × 107 Scoville heat units.
[edit] Pepper hotness: ASTA Pungency unit
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 15 times higher than Pungency units while measuring capsaicin, so a rough conversion is to multiply Pungency by 15 to obtain Scoville heat units.[19]
[edit] Radiation Dose: Strontium unit
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 × 10-12 grays/second. The permissible body burden was established at 1000 S.U.
[edit] Pain: Dol
See Dol.
[edit] References
- ^ c in furlongs per fortnight - Google Search. Retrieved on March 10, 2006.
- ^ FAQ for newsgroup UK.rec.sheds, version 2&3/7th (TXT) (2000). Retrieved on March 10, 2006.
- ^ Rear Admiral Grace Murray Hopper. U.S. Navy (4 May 2006). Retrieved on December 26, 2006.
- ^ The Jargon File - nanoacre. Retrieved on March 10, 2006.
- ^ Rhode Island as a Unit of Measure. Retrieved on March 10, 2006.
- ^ Australian Conventional Units of Measurement in Water (PDF). Australian Water Association. Retrieved on March 10, 2006.
- ^ The name "kilogram": a historical quirk. Bureau International des Poids et Mesures. Retrieved on March 10, 2006.
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- ^ "Geologic Time Galactic". "vendian.org". Retrieved on December 19, 2006.
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