The zero point of any thermodynamic temperature scale, such as Kelvin or Rankine, is set at absolute zero.

After James Prescott Joule had determined the mechanical equivalent of heat, Lord Kelvin approached the question from an entirely different point of view, and in 1848 devised a scale of absolute temperature which was independent of the properties of any particular substance and was based solely on the fundamental laws of thermodynamics.

The classical rule, recognized by Clausius and by Kelvin, is that the pressure exerted by the calorimetric material is fully and rapidly determined solely by its temperature and volume ; this rule is for changes that do not involve phase change, such as melting of ice.

The average temperature is between two and four million Kelvin, while the density goes from 10 < sup > 9 </ sup > to 10 < sup > 10 </ sup > particle per cm < sup > 3 </ sup >.

The fact that the Carnot function could be the temperature, measured from zero, was suggested by Joule in a letter to Kelvin, and this allowed Kelvin to establish his absolute temperature scale.

Absolute temperature refers to use of the Kelvin ( K ) or Rankine (° R ) temperature scales, with zero being absolute zero.

The Rankine temperature scale was created to use degree intervals the same size as those of the Fahrenheit scale, such that a temperature difference of one degree Rankine ( 1 R ) is equal to a difference of 1 ° F, except that absolute zero is 0 R – the same way that the Kelvin temperature scale matches the Celsius scale, except that absolute zero is 0 K. The Fahrenheit scale uses ( in the same manner as the later Celsius scale ) the symbol ° to denote a point on the temperature scale and the letter F to indicate the use of the Fahrenheit scale ( e. g. " Gallium melts at 85. 5763 ° F "), as well as to denote a difference between temperatures or an uncertainty in temperature ( e. g. " The output of the heat exchanger experiences an increase of 72 ° F " and " Our standard uncertainty is ± 5 ° F ").

On Earth, the cold side of any heat engine is limited to being close to the ambient temperature of the environment, or not much lower than 300 Kelvin, so most efforts to improve the thermodynamic efficiencies of various heat engines focus on increasing the temperature of the source, within material limits.

The central star itself is a white dwarf with a temperature of 120, 000 degrees Kelvin.

File: Joule James sitting. jpg | James Prescott Joule ( 1818-1889 ): discovered that heat is a form of energy, ideas led to the theory of conservation of energy, worked with Lord Kelvin to develop the absolute scale of temperature, made observations on magnetostriction, found the relationship between current through resistance and the heat dissipated, now called Joule's law.

However, throughout the entire scientific world thermodynamic temperature is measured using the Kelvin scale.

The stars being born in the Eagle Nebula, added to those with an approximate age of 5 million years have an average temperature of 45, 000 degrees Kelvin and produce prodigious amounts of radiation that will eventually destroy the dust pillars.

These fluctuations are known as Johnson – Nyquist noise or thermal noise and increase in proportion to the Kelvin temperature of any resistive component.

The contraction will proceed until the Hayashi limit is reached, and thereafter contraction will continue on a Kelvin – Helmholtz timescale with the temperature remaining stable.

Following Wiedemann – Franz law thermal conductivity of metals is approximately proportional to the absolute temperature ( in Kelvin ) times electrical conductivity.

By international agreement, absolute zero is defined as on the Kelvin scale and as − 273. 15 ° on the Celsius scale.

These are Kelvin ( SI units ) or Rankine scale ( Imperial & US units ).

( The Kelvin scale was first proposed in 1848.

Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale.

: Temperature – Celsius scale Kelvin scale Fahrenheit Rankine Rømer Réaumur DeLisle Newton

* 1848 — Lord Kelvin ( William Thomson )-Kelvin scale, in his paper, On an Absolute Thermometric Scale

He worked with Lord Kelvin to develop the absolute scale of temperature, made observations on magnetostriction, and found the relationship between the current through resistance and the heat dissipated, now one of the two laws called Joule's law.

The kilogram is one of the seven SI base units ; among these, it is one of three ( besides the second and the Kelvin ) which is defined ad hoc, without reference to another base unit, since 1889 by means of the international prototype kilogram.

) for the unit of entropy, calorie / Kelvin, but this usage did not become common and the corresponding SI unit, Joule / Kelvin, carries no special name.

In SI units, n is measured in moles, and T in kelvin ( 273. 15 Kelvin = 0 degrees Celsius ).

The ampere balance ( also current balance or Kelvin balance ) is an electromechanical apparatus used for the precise measurement of the SI unit of electric current, the ampere.

The degree Kelvin (° K ) is a former name for the SI unit of temperature on the thermodynamic ( absolute ) temperature scale.

Therefore, the triple point of water, for instance, is correctly written today as simply 273. 16 K. The SI fundamental temperature unit is now " kelvin " ( note the lower case ), and no longer " degree Kelvin ".

# REDIRECT Kelvin # SI prefixed forms of kelvin

* The age of the solar system, including Earth, was determined, and it turned to be much older than believed earlier: more than 4 billion years, rather than the 20 million years suggested by Lord Kelvin in 1862.

In systems where the substrate needs to be cooled, the ultra-high vacuum environment within the growth chamber is maintained by a system of cryopumps, and cryopanels, chilled using liquid nitrogen or cold nitrogen gas to a temperature close to 77 Kelvin (− 196 degrees Celsius ).

In 2009, it was discovered by NASA's Lunar Reconnaissance Orbiter that Hermite is the coldest place recorded in the solar system, with temperatures at 25 Kelvin (- 415 ° Fahrenheit, − 248 ° Celsius ).

In 1862, the Glaswegian physicist William Thomson ( later Lord Kelvin ) published calculations, based on his presumption of uniformitarianism, and that the heat of the sun was caused by its gravitational shrinkage, that fixed the age of the Earth and the solar system at between 20 million and 400 million years, i. e. between ~ 3, 000 and ~ 70, 000 times Ussher's value.

Price, who graduated through the Ipswich Town youth system, is an agile performer who became known for stepping in for Kelvin Davis during the 2004 – 05 season and saving a penalty against Coventry.

British scientists, philosophers and engineers have been at the forefront of the development of metrication – in 1668 John Wilkins first proposed a coherent system of units of measure, in 1861 a committee of the British Association for Advancement of Science ( BAAS ), including William Thomson ( later Lord Kelvin ), James Clerk Maxwell and Joule among its members, defined various electrical units in terms of metric rather than imperial units, and in the 1870s Johnson, Matthey & Co manufactured the international prototype metre and kilogram.

Through the efforts of Clausius and Kelvin, it is now known that the maximum work that can be done is the product of the Carnot efficiency and the heat absorbed at the hot reservoir:

While the Scottish Enlightenment is traditionally considered to have concluded toward the end of the 18th century, disproportionately large Scottish contributions to British science and letters continued for another 50 years or more, thanks to such figures as the mathematicians and physicists James Clerk Maxwell, Lord Kelvin, and the engineers and inventors James Watt and William Murdoch, whose work was critical to the technological developments of the Industrial Revolution throughout Britain.

In 1900, Lord Kelvin famously stated, " There is nothing new to be discovered in physics now.

Following the Kelvin effect ( based on the curvature of liquid droplets ) smaller particles need a higher ambient relative humidity to maintain equilibrium than bigger ones would.

Its first year saw the launch of both the Lunar Jetman strip ( written and illustrated by John Richardson, based on the character from the games by Ultimate Play The Game ) and The Terminal Man, an original piece of fiction written by Kelvin Gosnell and illustrated by Oliver Frey.

Kelvin Scottish Omnibuses Ltd was a bus operating subsidiary of the Scottish Transport Group based in Bishopbriggs, Strathclyde, Scotland.

When the book was written, the nature of the energy source that powers stars was not known: Lord Kelvin had published calculations based on the hypothesis that the energy came from the gravitational collapse of the gas cloud that had formed the sun, and found that this mechanism gave the Sun a lifetime of only a few tens of million of years.

Only the triple point of Vienna Standard Mean Ocean Water ( VSMOW ) is known with absolute precision — regardless of the calibration standard employed — because the very definitions of both the Kelvin and Celsius scales are fixed by international agreement based, in part, on this point.

Both temperatures must be measured using a thermodynamic temperature scale based at absolute zero such as Kelvin or Rankine.

: Friends of the River Kelvin River Kelvin based charity

The Kelvin probe force microscope or Kelvin force microscope ( KFM ) is based on an AFM set-up and the determination of the work function is based on the measurement of the electrostatic forces between the small AFM tip and the sample.

* Kelvin Diesels, a manufacturer of marine diesel engines, based in Glasgow

On July 20, 1893 following a famine in Madras Presidency, which underscored the need for a study of the sun to better understand monsoon patterns, a meeting of the U. K. Secretary of State, Indian Observatories Committee, chaired by Lord Kelvin, decided to establish a Solar physics Observatory at Kodaikanal, based on its southern, dust free, high altitude location.