Kelvin: Wikis

  
  

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Kelvin temperature conversion formulae
from Kelvin to Kelvin
Celsius [°C] = [K] − 273.15 [K] = [°C] + 273.15
Fahrenheit [°F] = [K] × 95 − 459.67 [K] = ([°F] + 459.67) × 59
Rankine [°R] = [K] × 95 [K] = [°R] × 59
For temperature intervals rather than specific temperatures,
1 K = 1 °C = 1.8 °F = 1.8 R
Comparisons among various temperature scales
The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. The Kelvin scale is a thermodynamic (absolute) temperature scale referenced to absolute zero, the theoretical absence of all thermal energy. By definition it is zero kelvins (0 K). The secondary reference point on the Kelvin scale is the triple point of water (0.01 degree Celsius). .The Kelvin scale is the difference between these two reference points, with the kelvin defined as one 273.16th of this scale.^ Switzerland and France, Letters from, written during a Residence of between two and three years in different parts of those countries.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

^ If you're ever at one of these events, and wonder at what point the candidate actually arrives, just look for when the national media arrives.
  • The Bucky Channel - The World of Sports from Wisconsin's Perspective.: February 2008 16 September 2009 11:34 UTC www.thebuckychannel.com [Source type: General]

^ When Daniel says "we're just on the wrong song" he is referring to the place in time they are in (like different songs are at different points on a record)...as in it is not where they were before Ben turned the wheel.
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

.The Kelvin scale and the kelvin are named after the Belfast-born physicist and engineer William Thomson, 1st Baron Kelvin (1824–1907), who wrote of the need for an "absolute thermometric scale". Unlike the degree Fahrenheit and degree Celsius, the kelvin is not referred to as a "degree", nor is it typeset with a degree symbol; that is, it is written K and not °K. The kelvin and the degree Celsius are often used together, as they have the same interval, and 0 kelvins is −273.15 degrees Celsius.^ In a post game interview with FSN's Scott Williams (who I think is great by the way), Cassell said the Bucks aren't far away from contending, they just need a leader.
  • The Bucky Channel - The World of Sports from Wisconsin's Perspective.: February 2008 16 September 2009 11:34 UTC www.thebuckychannel.com [Source type: General]

^ The Vetrans are getting killed until they say screw the boards and push the car over the sand using all 15 players......
  • The Bucky Channel - The World of Sports from Wisconsin's Perspective.: February 2008 16 September 2009 11:34 UTC www.thebuckychannel.com [Source type: General]

^ The logical, widely-held belief is that there are six survivors (thusly named the "Oceanic Six," as per Hurley's bellowing), and since we know there are more that six people who need to get off the island, Abaddon's "THEY" must refer to those left behind.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

Contents

History

1848
.Lord Kelvin (William Thomson), wrote in his paper, On an Absolute Thermometric Scale, of the need for a scale whereby "infinite cold" (absolute zero) was the scale’s null point, and which used the degree Celsius for its unit increment.^ Bombay, 1848 Thomson, Sir William (Lord Kelvin).
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

Thomson calculated that absolute zero was equivalent to −273 °C on the air thermometers of the time.[1] This absolute scale is known today as the Kelvin thermodynamic temperature scale. .It’s noteworthy that Thomson’s value of "−273" was actually derived from 0.00366, which was the accepted expansion coefficient of gas per degree Celsius relative to the ice point.^ The Radical Cause of the Present Distresses of the West-India Planters pointed out ; with Remarks on the Publications of Sir W. Young, C. Bosanquet, and J. Lowe, relative to the Value of the West-India Trade.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

The inverse of −0.00366 expressed to five significant digits is −273.22 °C which is remarkably close to the true value of −273.15 °C.
1954
Resolution 3 of the 10th CGPM gave the Kelvin scale its modern definition by designating the triple point of water as its second defining point and assigned its temperature to exactly "273.16 Kelvin."[2]
1967/1968
Resolution 3 of the 13th CGPM renamed the unit increment of thermodynamic temperature "kelvin", symbol K, replacing "degree absolute", symbol °K.[3] Furthermore, feeling it useful to more explicitly define the magnitude of the unit increment, the 13th CGPM also held in Resolution 4 that "The kelvin, unit of thermodynamic temperature, is equal to the fraction 1/273.16 of the thermodynamic temperature of the triple point of water."[4]
2005
.The Comité International des Poids et Mesures (CIPM), a committee of the CGPM, affirmed that for the purposes of delineating the temperature of the triple point of water, the definition of the Kelvin thermodynamic temperature scale would refer to water having an isotopic composition specified as VSMOW.^ Notice sur les Altitudes du Mont-Blanc et du Mont-Rose, deter- minees par des Mesures Barometriques et Geodesiques.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

^ Gilbert, Sir J. H. Remarques sur la Re- lation qui existe entre les Sommes de Temperature et la Production Agricole.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

^ St Petersburg, 1830 - Travaux de la Commission pour fixer les Mesures et Poids de Russie.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

[5]

Usage conventions

When reference is made to the unit kelvin (either a specific temperature or a temperature interval), kelvin is always spelled with a lowercase k unless it is the first word in a sentence.[6] When reference is made to the "Kelvin scale", the word "kelvin"—which is normally a noun—functions adjectivally to modify the noun "scale" and is capitalized.
.Until the 13th General Conference on Weights and Measures (CGPM) in 1967–1968, the unit kelvin was called a "degree", the same as with the other temperature scales at the time.^ I'm just following other exhaustive "Lost" time loop theories, or ones that haven't made much sense -- at least to me, an avid viewer -- until now.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

^ The Decimal System as a whole in its relation to Time, Measure, Weight, Capacity, and Money in unison with each other.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

^ Calcutta, 1859 Remarks on the Bombay Tidal Ob- servations for 1 86 1, and other Papers relative to the Tides, Weights, and Measures, &c.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

.It was distinguished from the other scales with either the adjective suffix "Kelvin" ("degree Kelvin") or with "absolute" ("degree absolute") and its symbol was °K. The latter (degree absolute), which was the unit’s official name from 1948 until 1954, was rather ambiguous since it could also be interpreted as referring to the Rankine scale.^ I also can't delve too deeply into the show's bookshelf since I've basically ignored all the other literary reference that came before.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

Before the 13th CGPM, the plural form was "degrees absolute". The 13th CGPM changed the name to simply "kelvin" (symbol K).[7] The omission of "degree" indicates that it is not relative to an arbitrary reference point like the Celsius and Fahrenheit scales, but rather an absolute unit of measure which can be manipulated algebraically (e.g., multiplied by two to indicate twice the amount of "mean energy" available among elementary degrees of freedom of the system).
This SI unit is named after William Thomson, 1st Baron Kelvin. .As with every SI unit whose name is derived from the proper name of a person, the first letter of its symbol is uppercase (K).^ I&S9 Verba Nominalia, or Words Derived from Proper Names.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

^ A Vocabulary of Proper Names, in Chinese and English, of Places, Persons, Tribes, and Sects in China, Japan, Corea, Annam, Siam, Burmah, the Straits, and adjacent Countries.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

When an SI unit is spelled out in English, it should always begin with a lowercase letter (kelvin), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.
Based on The International System of Units, section 5.2.
.The kelvin symbol is always a roman, non-italic capital K. In the SI naming convention, all symbols named after a person are capitalized; in the case of the kelvin, capitalizing also distinguishes the symbol from the SI prefix "kilo", which has the lowercase k as its symbol.^ PS In case no one knew, Socratic dialogues are named for the main person Socrates is talking with.
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

The admonition against italicizing the symbol K applies to all SI unit symbols; only symbols for variables and constants (e.g., P = pressure, and c = 299,792,458 m/s) are italicized in scientific and engineering papers. As with most other SI unit symbols (angle symbols, e.g. 45° 3′ 4″, are the exception) there is a space between the numeric value and the kelvin symbol (e.g. "99.987 K").[8][9]
Unicode provides a compatibility character for the kelvin at U+212A (decimal 8490), for compatibility with CJK encodings that provide such a character (as such, in most fonts the width is the same as for fullwidth characters).

Use in conjunction with Celsius

In science and in engineering, the Celsius scale and the kelvin are often used simultaneously in the same article (e.g., "...its measured value was 0.01028 °C with an uncertainty of 60 µK..."). .This practice is permissible because the degree Celsius is a special name for the kelvin for use in expressing Celsius temperatures and the magnitude of the degree Celsius is exactly equal to that of the kelvin.^ The dashboard also displayed a temperature of 23 degrees Celsius and 42 km on the odometer.
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

^ I mean she knows all the secrets, because her Bill Cosby (yes, I am using Dr. Cosby's name interchangeably with "ghost dad") told her everything.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

[10] .Notwithstanding that the official endorsement provided by Resolution 3 of the 13th CGPM states, "a temperature interval may also be expressed in degrees Celsius," the practice of simultaneously using both "°C" and "K" remains widespread throughout the scientific world as the use of SI prefixed forms of the degree Celsius (such as "µ°C" or "microdegrees Celsius") to express a temperature interval has not been widely adopted.^ The dashboard also displayed a temperature of 23 degrees Celsius and 42 km on the odometer.
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

^ A class on World Religion as it pertains to "Lost" would provide students with all the necessary background reading for understanding the symbolism the show uses on a weekly basis.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

^ The one aim kept in view was to produce a Catalogue of the most con- venient form for the use of Fellows of the Society and practical geographers.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

A helpful way to think of the kelvin system is thinking that nothing can be colder than 0 kelvin (-273.15 degrees Celsius). [3]

Proposed redefinition

.In 2005 the CIPM embarked on a program to redefine, amongst others, the Kelvin using a more rigorous basis than was in use.^ Plus I don't think he quite knows what to do - and likely doesn't want to say anything to anyone other than his 'posse' - the more who know, the more can spill...
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

^ Wonder if him being all over - both on- and off-island - makes him more dangerous than others.
  • The Lost Diary: LaFleur 19 January 2010 9:53 UTC thelostdiary.com [Source type: General]

^ I have more questions after this episode than probably any other I've watched.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

.The current (2010) definition is unsatisfactory for temperatures below 20 K and above 1300 K.[11] It is anticipated that the program will be completed in time for its adoption by the CGPM at its 2011 meeting.^ The biggest one -- that completely obliterates my concept of time travel, mind travel, whatever -- is that Desmond and Faraday did not have to meet in 1996 to end up on the island.
  • Channel Surfing | greenbaypressgazette.com | Green Bay Press-Gazette 16 September 2009 11:34 UTC www.greenbaypressgazette.com [Source type: General]

The committee proposes defining the kelvin as the temperature scale for which Boltzmann's Constant is 1.380 650 5 × 10−23 J/K exactly.
From a scientific point of view, this will link temperature to the rest of SI and result in a stable definition that is independent of any particular substance. From a practical point of view the redefinition will pass unnoticed; water will still freeze at 0 °C (273.16 K).[12]

Practical uses

Color temperature

The kelvin is often used in the measure of the color temperature of light sources. Color temperature is based upon the principle that a black body radiator emits light whose color depends on the temperature of the radiator. Black bodies with temperatures below about 4000 K appear reddish whereas those above about 7500 K appear bluish. Color temperature is important in the fields of image projection and photography where a color temperature of approximately 5600 K is required to match "daylight" film emulsions. .In astronomy, the stellar classification of stars and their place on the Hertzsprung-Russell diagram are based, in part, upon their surface temperature, known as effective temperature.^ Diagram, 8* \Sydf v, 1880] Russell, H. C. Some New Double Stars and Southern Binaries.
  • Full text of "Catalogue of the library of the Royal geographical society. Containing the titles of all works up to December 1893" 19 January 2010 9:53 UTC www.archive.org [Source type: Academic]

The photosphere of the Sun, for instance, has an effective temperature of 5778 K.

Kelvin as a measure of noise

In electronics, the kelvin is used as an indicator of how noisy a circuit is in relation to an ultimate noise floor, i.e. the noise temperature. The so-called Johnson–Nyquist noise of discrete resistors and capacitors is a type of thermal noise derived from the Boltzmann constant and can be used to determine the noise temperature of a circuit using the Friis formulas for noise.

See also

References

  1. ^ Thomson, William (October 1848). "On an Absolute Thermometric Scale". Philosophical Magazine. http://zapatopi.net/kelvin/papers/on_an_absolute_thermometric_scale.html. Retrieved 2008-02-06. 
  2. ^ "Resolution 3: Definition of the thermodynamic temperature scale". Resolutions of the 10th CGPM. Bureau International des Poids et Mesures. 1954. http://www.bipm.fr/en/CGPM/db/10/3/. Retrieved 2008-02-06. 
  3. ^ a b "Resolution 3: SI unit of thermodynamic temperature (kelvin)". Resolutions of the 13th CGPM. Bureau International des Poids et Mesures. 1967. http://www.bipm.fr/en/CGPM/db/13/3/. Retrieved 2008-02-06. 
  4. ^ "Resolution 4: Definition of the SI unit of thermodynamic temperature (kelvin)". Resolutions of the 13th CGPM. Bureau International des Poids et Mesures. 1967. http://www.bipm.fr/en/CGPM/db/13/4/. Retrieved 2008-02-06. 
  5. ^ "Unit of thermodynamic temperature (kelvin)". SI Brochure, 8th edition. Bureau International des Poids et Mesures. 1967. pp. Section 2.1.1.5. http://www1.bipm.org/en/si/si_brochure/chapter2/2-1/2-1-1/kelvin.html. Retrieved 2008-02-06. 
  6. ^ BIPM: SI brochure, Section 5.2
  7. ^ Barry N. Taylor (2008) (.PDF). Guide for the Use of the International System of Units (SI). Special Publication 811. National Institute of Standards and Technology. http://physics.nist.gov/Document/sp811.pdf. Retrieved 2009-06-24. 
  8. ^ "SI Unit rules and style conventions". National Institute of Standards and Technology. September 2004. http://physics.nist.gov/cuu/Units/checklist.html. Retrieved 2008-02-06. 
  9. ^ "Rules and style conventions for expressing values of quantities". SI Brochure, 8th edition. Bureau International des Poids et Mesures. 1967. pp. Section 5.3.3. http://www.bipm.org/en/si/si_brochure/chapter5/5-3-2.html#5-3-3. Retrieved 2008-02-06. 
  10. ^ "Units with special names and symbols; units that incorporate special names and symbols". SI Brochure, 8th edition. Bureau International des Poids et Mesures. 2006. pp. Section 2.2.2, Table 3. http://www.bipm.org/en/si/si_brochure/chapter2/2-2/table3.html. Retrieved 2008-02-06. 
  11. ^ J. Fischer1 et al. "Report to the CIPM on the implications of changing the definition of the base unit Kelvin". International Committee for Weights and Measures (CIPM). http://www.bipm.org/wg/CCT/TG-SI/Allowed/Documents/Report_to_CIPM_2.pdf. Retrieved 2010-02-23. 
  12. ^ "Updating the definition of the kelvin". International Bureau for Weights and Measures (BIPM). http://www.bipm.org/wg/CCT/TG-SI/Allowed/Documents/Updating_the_definition_of_the_kelvin2.pdf. Retrieved 2010-02-23. 

External links


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

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Wikipedia has an article on:
See also kelvin

English

Proper noun

Singular
Kelvin
Plural
-
Kelvin
  1. A river in Scotland, running through Glasgow.
  2. A surname.
  3. A male given name transferred from the surname; rather rare.

Derived terms


Simple English

File:Lord Kelvin
Lord Kelvin

The kelvin (symbol: K) is the SI unit of temperature. It is named in honour of the physicist William Thomson, the first Lord Kelvin (1824–1907).

Definition

The Kelvin scale is defined by a specific relationship between the pressure of a gas and the temperature. This says that "the pressure of the gas is directly proportional to the temperature in Kelvin". This means that Kelvin is an absolute temperature scale, and scientists use this scale more than any other.

The kelvin is a base SI unit of measurement, defined as the fraction 1/273.16 of the temperature of the triple point of water, which is the temperature at which water in solid, liquid, and gaseous state coexist in equilibrium.

The temperature of the triple point of water is a hundredth of a degree Celsius above the freezing point, or 0.01 °C. The coldest possible temperature is called absolute zero and is equal to -273.15 degrees Celsius, or zero kelvin (0 K). By writing temperatures in kelvins one does not need to use negative numbers.

The absolute temperature scale was designed so that a change in temperature of 1 kelvin is equal to a change of 1 degree Celsius. This means that it is easy to convert a temperature from degrees Celsius to kelvins.

  • To convert a temperature originally expressed in degrees Celsius into kelvins you must add 273.15 units. For example 0 degrees Celsius (0 °C), which is the temperature at which water freezes, is 273.15 kelvins (273.15 K).
  • To convert a temperature originally expressed in kelvins into degrees Celsius you must subtract 273.15 units. For example 310 kelvins is 36.85 degrees Celsius, which is roughly the normal temperature of a human body.

It is important to notice that the name of this unit is simply kelvin (with a lowercase initial), not "degree Kelvin". In English, it undergoes normal plural inflection as kelvins.

Other pages


Citable sentences

Up to date as of December 14, 2010

Here are sentences from other pages on Kelvin, which are similar to those in the above article.








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