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James Prescott Joule (; 24 December 1818 11 October 1889) was an English
physicist A physicist is a scientist A scientist is a person who conducts scientific research The scientific method is an Empirical evidence, empirical method of acquiring knowledge that has characterized the development of science since at leas ...

physicist
,
mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics as numbers (arithmetic and number theory), formulas and related structures (algebra), shapes and spaces ...

mathematician
and
brewer Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and #Fermenting, fermenting the resulting sweet liquid with Yeast#Beer, yeast. It may be done in a brewer ...
, born in
Salford Salford () is the second-largest city in Greater Manchester, England. It is the principal settlement of the City of Salford. In 2011, Salford had a population of 103,886, Salford is located in a meander of the River Irwell which forms part of ...
,
Lancashire Lancashire ( , ; abbreviated Lancs.) is a non-metropolitan and ceremonial county The counties and areas for the purposes of the lieutenancies, also referred to as the lieutenancy areas of England and informally known as ceremonial co ...

Lancashire
. Joule studied the nature of
heat In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these ...

heat
, and discovered its relationship to
mechanical work In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. ...
(see
energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regula ...

energy
). This led to the
law of conservation of energy In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through ...
, which in turn led to the development of the
first law of thermodynamics The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing three kinds of transfer of energy, as heat, as thermodynamic work, and as energy associated with matter tran ...
. The
SI derived unit SI derived units are units of measurement derived from the seven SI base unit, base units specified by the International System of Units (SI). They are either dimensionless quantity, dimensionless or can be expressed as a product of one or more o ...
of energy, the
joule The joule ( ; symbol: J) is a derived unit of energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates ...

joule
, is named after him. He worked with
Lord Kelvin William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics ...
to develop an absolute thermodynamic
temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical concept ...

temperature
scale, which came to be called the
Kelvin The kelvin is the base unit of temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal en ...

Kelvin
scale. Joule also made observations of
magnetostriction Magnetostriction (cf. electrostriction) is a property of magnet, magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field ...
, and he found the relationship between the
current Currents or The Current may refer to: Science and technology * Current (fluid) A current in a fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. ...
through a
resistor A resistor is a passive Passive may refer to: * Passive voice, a grammatical voice common in many languages, see also Pseudopassive (disambiguation), Pseudopassive * Passive language, a language from which an interpreter works * Passivity (b ...

resistor
and the heat dissipated, which is also called
Joule's first law Joule heating, also known as resistive, resistance, or Ohmic heating, is the process by which the passage of an electric current through a conductor produces heat. Joule's first law, also known as the Joule–Lenz law, :(''Energy dissipated pe ...
. His experiments about energy transformations were first published in 1843.


Early years

James Joule was born in 1818, the son of Benjamin Joule (1784–1858), a wealthy
brewer Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and #Fermenting, fermenting the resulting sweet liquid with Yeast#Beer, yeast. It may be done in a brewer ...

brewer
, and his wife, Alice Prescott, on New Bailey Street in
Salford Salford () is the second-largest city in Greater Manchester, England. It is the principal settlement of the City of Salford. In 2011, Salford had a population of 103,886, Salford is located in a meander of the River Irwell which forms part of ...
. Joule was tutored as a young man by the famous scientist
John Dalton John Dalton (; 6 September 1766 – 27 July 1844) was an English chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin Medieval Latin was the form of Latin Latin (, or , ) is a classical ...

John Dalton
and was strongly influenced by chemist William Henry and
Manchester Manchester () is the most-populous city and metropolitan borough A metropolitan borough is a type of local government district The districts of England (also known as local authority districts or local government districts to distinguis ...

Manchester
engineers
Peter Ewart Peter Ewart (14 May 1767 – 15 September 1842) was a British engineer Engineers, as practitioners of engineering, are Professional, professionals who Invention, invent, design, analyze, build and test Machine, machines, complex systems, ...
and
Eaton Hodgkinson Eaton A. Hodgkinson Fellow of the Royal Society, FRS (26 February 1789 – 18 June 1861) was an England, English engineer, a pioneer of the application of mathematics to problems of structural design. Early life Hodgkinson was born in the villa ...
. He was fascinated by
electricity Electricity is the set of physical Physical may refer to: *Physical examination, a regular overall check-up with a doctor *Physical (album), ''Physical'' (album), a 1981 album by Olivia Newton-John **Physical (Olivia Newton-John song), "Physi ...

electricity
, and he and his brother experimented by giving electric shocks to each other and to the family's servants. As an adult, Joule managed the brewery. Science was merely a serious hobby. Sometime around 1840, he started to investigate the feasibility of replacing the brewery's
steam engine from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energ ...

steam engine
s with the newly invented
electric motor
electric motor
. His first
scientific paper : ''For a broader class of literature, see Academic publishing Academic publishing is the subfield of publishing which distributes academic research and scholarship. Most academic work is published in academic journal articles, books or thes ...
s on the subject were contributed to
William Sturgeon William Sturgeon (22 May 1783 – 4 December 1850) was an England, English physicist and inventor who made the first electromagnets, and invented the first practical British electric motor. Early life Sturgeon was born on 22 May 1783 in Whit ...

William Sturgeon
's ''Annals of Electricity''. Joule was a member of the
London Electrical SocietyThe London Electrical Society was established in 1837 to enable amateur electricians to meet and share their interests in “experimental investigation of Electrical Science in all its various branches”. Although it initially flourished the society ...
, established by Sturgeon and others. Motivated in part by a businessman's desire to quantify the
economics Economics () is a social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and interact ...

economics
of the choice, and in part by his scientific inquisitiveness, he set out to determine which prime mover was more efficient. He discovered
Joule's first law Joule heating, also known as resistive, resistance, or Ohmic heating, is the process by which the passage of an electric current through a conductor produces heat. Joule's first law, also known as the Joule–Lenz law, :(''Energy dissipated pe ...
in 1841, that ''the
heat In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these ...

heat
which is evolved by the proper action of any
voltaic current
voltaic current
is proportional to the square of the intensity of that current, multiplied by the resistance to conduction which it experiences''. He went on to realize that burning a
pound Pound or Pounds may refer to: Units * Pound (currency) A pound is any of various units of currency A currency, "in circulation", from la, currens, -entis, literally meaning "running" or "traversing" in the most specific sense is money Im ...
of coal in a steam engine was more economical than a costly pound of
zinc Zinc is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical element ...

zinc
consumed in an electric
battery Battery may refer to: Energy source * Electric battery, an electrochemical device to provide electrical power ** Automotive battery, a device to provide power to certain functions of an automobile ** List of battery types * Energy storage, inclu ...
. Joule captured the output of the alternative methods in terms of a common standard, the ability to raise a mass weighing one pound to a height of one
foot The foot (plural: feet) is an anatomical Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemis ...
, the ''foot-pound''. However, Joule's interest diverted from the narrow financial question to that of how much work could be extracted from a given source, leading him to speculate about the convertibility of
energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regula ...

energy
. In 1843 he published results of experiments showing that the
heat In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these ...

heat
ing effect he had quantified in 1841 was due to generation of heat in the
conductor Conductor or conduction may refer to: Music * Conductor (music), a person who leads a musical ensemble like, for example, an orchestra. * Conductor (album), ''Conductor'' (album), an album by indie rock band The Comas * Conduction, a type of ...
and not its transfer from another part of the equipment. This was a direct challenge to the
caloric theory The caloric theory is an obsolete scientific theory In Science#History, science, a theory is superseded when a scientific consensus once widely accepted it, but current science considers it inadequate, incomplete, or debunked (i.e., wrong). Such ...
which held that heat could neither be created or destroyed. Caloric theory had dominated thinking in the science of heat since introduced by
Antoine Lavoisier Antoine-Laurent de Lavoisier ( , ,; 26 August 17438 May 1794), When reduced without charcoal, it gave off an air which supported respiration and combustion in an enhanced way. He concluded that this was just a pure form of common air and t ...

Antoine Lavoisier
in 1783. Lavoisier's prestige and the practical success of Sadi Carnot's caloric theory of the
heat engine In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do work (physics), mechanical work. It does this by bringing a working substance from a higher state temperature to ...

heat engine
since 1824 ensured that the young Joule, working outside either
academia An academy (Attic Greek Attic Greek is the Greek language, Greek dialect of the regions of ancient Greece, ancient region of Attica, including the ''polis'' of classical Athens, Athens. Often called classical Greek, it was the prestige (sociol ...

academia
or the
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...

engineering
profession, had a difficult road ahead. Supporters of the caloric theory readily pointed to the symmetry of the Peltier–Seebeck effect to claim that heat and current were convertible in an, at least approximately, reversible process.


The mechanical equivalent of heat

Further experiments and measurements with his electric motor led Joule to estimate the ''
mechanical equivalent of heat In the history of science The history of science is the study of the development of science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), ...
'' as 4.1868
joules The joule ( ; symbol: J) is a derived unit of energy In physics, energy is the physical quantity, quantitative physical property, property that must be #Energy transfer, transferred to a physical body, body or physical system to perform W ...
per
calorie The calorie is a unit of energy Unit may refer to: Arts and entertainment * UNIT Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a di ...
of work to raise the temperature of one gram of water by one Kelvin. He announced his results at a meeting of the chemical section of the
British Association for the Advancement of Science The British Science Association (BSA) is a charity Charity may refer to: Giving * Charitable organization or charity, a non-profit organization whose primary objectives are philanthropy and social well-being * Charity (practice), the practice ...
in
Cork Cork or CORK may refer to: Materials * Cork (material), an impermeable buoyant plant product ** Cork (plug), a cylindrical or conical object used to seal a container ***Wine cork Places Ireland * Cork (city) ** Metropolitan Cork, also known as G ...
in August 1843 and was met by silence. Joule was undaunted and started to seek a purely mechanical demonstration of the conversion of work into heat. By forcing water through a perforated cylinder, he could measure the slight
viscous The viscosity of a fluid In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, ...

viscous
heating of the fluid. He obtained a mechanical equivalent of . The fact that the values obtained both by electrical and purely mechanical means were in agreement to at least one
order of magnitude An order of magnitude is an approximation of the logarithm In mathematics, the logarithm is the inverse function to exponentiation. That means the logarithm of a given number  is the exponent to which another fixed number, the ''base (ex ...
was, to Joule, compelling evidence of the reality of the convertibility of work into heat. Joule now tried a third route. He measured the heat generated against the work done in compressing a gas. He obtained a mechanical equivalent of . In many ways, this experiment offered the easiest target for Joule's critics but Joule disposed of the anticipated objections by clever experimentation. Joule read his paper to the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society A learned society (; also known as a learned academy, scholarly society, or academic association) is an organization that exis ...
on 20 June 1844, but his paper was rejected for publication by the Royal Society and he had to be content with publishing in the ''
Philosophical Magazine The ''Philosophical Magazine'' is one of the oldest scientific journal In academic publishing Academic publishing is the subfield of publishing Publishing is the activity of making information, literature, music, software and other ...
'' in 1845. In the paper he was forthright in his rejection of the caloric reasoning of Carnot and Émile Clapeyron, a rejection partly theologically driven: Joule here adopts the language of ''vis viva'' (energy), possibly because Hodgkinson had read a review of Ewart's ''On the measure of moving force'' to the Literary and Philosophical Society in April 1844. Joule wrote in his 1844 paper: In June 1845, Joule read his paper ''On the Mechanical Equivalent of Heat'' to the British Association meeting in
Cambridge Cambridge ( ) is a university city and the county town In the United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' ...

Cambridge
. In this work, he reported his best-known experiment, involving the use of a falling weight, in which gravity does the mechanical work, to spin a
paddle wheel A paddle wheel is a form of waterwheel A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or ...

paddle wheel
in an insulated barrel of water which increased the temperature. He now estimated a mechanical equivalent of . He wrote a letter to the Philosophical Magazine, published in September 1845 describing his experiment. In 1850, Joule published a refined measurement of , closer to twentieth century estimates.


Reception and priority

Much of the initial resistance to Joule's work stemmed from its dependence upon extremely
precise
precise
measurement Measurement is the quantification (science), quantification of variable and attribute (research), attributes of an object or event, which can be used to compare with other objects or events. The scope and application of measurement are dependen ...

measurement
s. He claimed to be able to measure temperatures to within of a degree Fahrenheit (3 mK). Such precision was certainly uncommon in contemporary experimental physics but his doubters may have neglected his experience in the art of brewing and his access to its practical technologies. He was also ably supported by
scientific instrument A scientific instrument is a device or tool used for scientific purposes, including the study of both natural phenomena and theoretical research. History Historically, the definition of a scientific instrument has varied, based on usage, laws, and ...

scientific instrument
-maker
John Benjamin Dancer John Benjamin Dancer (8 October 1812 – 24 November 1887) was a British scientific instrument maker and inventor of microphotography. He also pioneered stereography. By 1835, he controlled his father's instrument making business in Liverpool. He ...
. Joule's experiments complemented the theoretical work of
Rudolf Clausius Rudolf Julius Emanuel Clausius (; 2 January 1822 – 24 August 1888) was a German German(s) may refer to: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citize ...
, who is considered by some to be the coinventor of the energy concept. Joule was proposing a kinetic theory of heat (he believed it to be a form of rotational, rather than translational,
kinetic energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular ...
), and this required a conceptual leap: if heat was a form of molecular motion, why didn't the motion of the molecules gradually die out? Joule's ideas required one to believe that the collisions of molecules were perfectly elastic. Importantly, the very existence of
atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of ato ...

atom
s and
molecule A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon ...

molecule
s was not widely accepted for another 50 years. Although it may be hard today to understand the allure of the
caloric theory The caloric theory is an obsolete scientific theory In Science#History, science, a theory is superseded when a scientific consensus once widely accepted it, but current science considers it inadequate, incomplete, or debunked (i.e., wrong). Such ...
, at the time it seemed to have some clear advantages. Carnot's successful theory of heat engines had also been based on the caloric assumption, and only later was it proved by
Lord Kelvin William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics ...
that Carnot's mathematics were equally valid without assuming a caloric fluid. However, in Germany,
Hermann Helmholtz Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physicist A physicist is a scientist A scientist is a person who conducts scientific research The scientific method is an Empirical eviden ...
became aware both of Joule's work and the similar 1842 work of
Julius Robert von Mayer Julius Robert von Mayer (25 November 1814 – 20 March 1878) was a German physician A physician (American English), medical practitioner (English in the Commonwealth of Nations, Commonwealth English), medical doctor, or simply doctor, is a ...

Julius Robert von Mayer
. Though both men had been neglected since their respective publications, Helmholtz's definitive 1847 declaration of the
conservation of energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular s ...
credited them both. Also in 1847, another of Joule's presentations at the British Association in
Oxford Oxford () is a city in England. It is the county town In the United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' u ...

Oxford
was attended by
George Gabriel Stokes Sir George Gabriel Stokes, 1st Baronet, (; 13 August 1819 – 1 February 1903) was an Irish English physicist A physicist is a scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge ...

George Gabriel Stokes
,
Michael Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist A scientist is a person who conducts scientific research The scientific method is an Empirical evidence, empirical method of acquiring knowledge ...

Michael Faraday
, and the precocious and maverick William Thomson, later to become Lord Kelvin, who had just been appointed professor of
natural philosophy Natural philosophy or philosophy of nature (from Latin ''philosophia naturalis'') was the philosophy, philosophical study of nature and the physical universe that was dominant before the development of modern science. From the ancient world, a ...
at the
University of Glasgow The University of Glasgow (abbreviated as ''Glas.'' in Post-nominal letters, post-nominals; ) is a Public university, public research university in Glasgow, Scotland. Founded by papal bull in 1451, it is the List of oldest universities in continuous ...

University of Glasgow
. Stokes was "inclined to be a Joulite" and Faraday was "much struck with it" though he harboured doubts. Thomson was intrigued but sceptical. Unanticipated, Thomson and Joule met later that year in
Chamonix Chamonix-Mont-Blanc ( frp, Chamôni), more commonly known as Chamonix, is a commune A commune is an intentional community of people sharing living spaces, interests, values, beliefs, and often property Property (''latin: Res Privata'') ...

Chamonix
. Joule married Amelia Grimes on 18 August and the couple went on honeymoon. Marital enthusiasm notwithstanding, Joule and Thomson arranged to attempt an experiment a few days later to measure the temperature difference between the top and bottom of the Cascade de Sallanches waterfall, though this subsequently proved impractical. Though Thomson felt that Joule's results demanded theoretical explanation, he retreated into a spirited defence of the Carnot-Clapeyron school. In his 1848 account of
absolute temperature Thermodynamic temperature is a quantity defined in thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of ...
, Thomson wrote that "the conversion of heat (or caloric) into mechanical effect is probably impossible, certainly undiscovered" – but a footnote signalled his first doubts about the caloric theory, referring to Joule's "very remarkable discoveries". Surprisingly, Thomson did not send Joule a copy of his paper but when Joule eventually read it he wrote to Thomson on 6 October, claiming that his studies had demonstrated conversion of heat into work but that he was planning further experiments. Thomson replied on the 27th, revealing that he was planning his own experiments and hoping for a reconciliation of their two views. Though Thomson conducted no new experiments, over the next two years he became increasingly dissatisfied with Carnot's theory and convinced of Joule's. In his 1851 paper, Thomson was willing to go no further than a compromise and declared "the whole theory of the motive power of heat is founded on two propositions, due respectively to Joule, and to Carnot and Clausius". As soon as Joule read the paper he wrote to Thomson with his comments and questions. Thus began a fruitful, though largely epistolary, collaboration between the two men, Joule conducting experiments, Thomson analysing the results and suggesting further experiments. The collaboration lasted from 1852 to 1856, its discoveries including the
Joule–Thomson effect In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quant ...
, and the published results did much to bring about general acceptance of Joule's work and the
kinetic theory of the ideal gas An ideal gas is a theoretical gas composed of many randomly moving point particles that are not subject to interparticle interactions. The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation o ...

kinetic theory
.


Kinetic theory

Kinetics is the science of motion. Joule was a pupil of Dalton and it is no surprise that he had learned a firm belief in the
atomic theory Atomic theory is the scientific theory A scientific theory is an explanation of an aspect of the that has been and verified in accordance with the , using accepted of , measurement, and evaluation of results. Where possible, theories are ...
, even though there were many scientists of his time who were still skeptical. He had also been one of the few people receptive to the neglected work of
John Herapath John Herapath (30 May 1790 – 24 February 1868) was an English physicist A physicist is a scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of science, area of interes ...
on the
kinetic theory of gases The kinetic theory of gases is a simple, historically significant classical Classical may refer to: European antiquity *Classical antiquity, a period of history from roughly the 7th or 8th century B.C.E. to the 5th century C.E. centered on the M ...

kinetic theory of gases
. He was further profoundly influenced by
Peter Ewart Peter Ewart (14 May 1767 – 15 September 1842) was a British engineer Engineers, as practitioners of engineering, are Professional, professionals who Invention, invent, design, analyze, build and test Machine, machines, complex systems, ...
's 1813 paper ''On the measure of moving force''. Joule perceived the relationship between his discoveries and the kinetic theory of heat. His laboratory notebooks reveal that he believed heat to be a form of rotational, rather than translational motion. Joule could not resist finding antecedents of his views in
Francis Bacon Francis Bacon, 1st Viscount St Alban, (; 22 January 1561 – 9 April 1626), also known as Lord Verulam, was an English philosopher and statesman who served as Attorney General for England and Wales, Attorney General and as Lord Chancellor of K ...

Francis Bacon
, Sir
Isaac Newton Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics a ...

Isaac Newton
,
John Locke John Locke (; 29 August 1632 – 28 October 1704) was an English philosopher and physician, widely regarded as one of the most influential of Enlightenment Enlightenment, enlighten or enlightened may refer to: Age of Enlightenment * ...

John Locke
,
Benjamin Thompson (Count Rumford)
Benjamin Thompson (Count Rumford)
and Sir
Humphry Davy Sir Humphry Davy, 1st Baronet (17 December 177829 May 1829) was a Cornish Cornish is the adjective and demonym associated with Cornwall, the most southwesterly part of the United Kingdom. It may refer to: * Cornish language, a Brittonic South ...

Humphry Davy
. Though such views are justified, Joule went on to estimate a value for the mechanical equivalent of heat of 1,034 foot-pound from Rumford's publications. Some modern writers have criticised this approach on the grounds that Rumford's experiments in no way represented systematic quantitative measurements. In one of his personal notes, Joule contends that Mayer's measurement was no more
accurate In a set of measurements, accuracy is closeness of the measurements to a specific value, while precision is the closeness of the measurements to each other. ''Accuracy'' has two definitions: # More commonly, it is a description of ''systematic err ...

accurate
than Rumford's, perhaps in the hope that Mayer had not anticipated his own work. Joule has been attributed with explaining the sunset
green flash The green flash and green ray are meteorological Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting Weather forecasting is t ...

green flash
phenomenon in a letter to the
Manchester Literary and Philosophical Society The Manchester Literary and Philosophical Society, popularly known as the Lit. & Phil., is one of the oldest learned society, learned societies in the United Kingdom and second oldest provincial learned society (after the Spalding Gentlemen's S ...
in 1869; actually, he merely noted (with a sketch) the last glimpse as bluish green, without attempting to explain the cause of the phenomenon.


Published work

* * * * * * * * *


Honours

Joule died at home in Sale and is buried in
Brooklands Brooklands was a Auto racing, motor racing circuit and aerodrome built near Weybridge in Surrey, England, United Kingdom. It opened in 1907 and was the world's first purpose-built 'banked' motor racing circuit as well as one of Britain's firs ...
cemetery there. His gravestone is inscribed with the number "772.55", his climacteric 1878 measurement of the mechanical equivalent of heat, in which he found that this amount of
foot-pounds The foot-pound force (symbol: ft⋅lbf, ft⋅lbf, or ft⋅lb ) is a unit of Mechanical work, work or energy in the English Engineering Units, engineering and Foot–pound–second_system#force, gravitational systems in United States customary u ...
of work must be expended at sea level to raise the
temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical concept ...

temperature
of one
pound Pound or Pounds may refer to: Units * Pound (currency) A pound is any of various units of currency A currency, "in circulation", from la, currens, -entis, literally meaning "running" or "traversing" in the most specific sense is money Im ...
of water from to . There is also a quotation from the Gospel of John: "I must work the work of him that sent me, while it is day: the night cometh, when no man can work". The Wetherspoon's pub in Sale, the town of his death, is named "The J. P. Joule" after him. Joule's family brewery survives to this day but is now located in Market Drayton. Joule's many honours and commendations include: *Fellow of the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society A learned society (; also known as a learned academy, scholarly society, or academic association) is an organization that exis ...
(1850) **Royal Medal (1852), 'For his paper on the mechanical equivalent of heat, printed in the Philosophical Transactions for 1850' **Copley Medal (1870), 'For his experimental researches on the dynamical theory of heat' *President of
Manchester Literary and Philosophical Society The Manchester Literary and Philosophical Society, popularly known as the Lit. & Phil., is one of the oldest learned society, learned societies in the United Kingdom and second oldest provincial learned society (after the Spalding Gentlemen's S ...
(1860) *President of the
British Association for the Advancement of Science The British Science Association (BSA) is a charity Charity may refer to: Giving * Charitable organization or charity, a non-profit organization whose primary objectives are philanthropy and social well-being * Charity (practice), the practice ...
(1872, 1887) *Honorary Membership of the Institution of Engineers and Shipbuilders in Scotland (1857) *Honorary degrees: **Doctor of Laws, LL.D., Trinity College, Dublin (1857) **Doctor of Civil Law, DCL, University of Oxford (1860) **LL.D., University of Edinburgh (1871) *Joule received a civil list pension of GBP, £200 ''per annum'' in 1878 for services to science *Albert Medal (RSA), Albert Medal of the Royal Society of Arts (1880), 'for having established, after most laborious research, the true relation between heat, electricity and mechanical work, thus affording to the engineer a sure guide in the application of science to industrial pursuits' There is a memorial to Joule in the north choir aisle of Westminster Abbey, though he is not buried there, contrary to what some biographies state. A statue of Joule by Alfred Gilbert stands in Manchester Town Hall, opposite that of Dalton.


Family

In 1847, Joule married Amelia Grimes. Joule became a widower when she died in 1854, 7 years after their wedding. They had three children together: a son, Benjamin Arthur Joule (1850–1922), a daughter, Alice Amelia (1852–1899) and a second son, Joe (born 1854, who died three weeks later).


See also

*Latent heat *Sensible heat *Internal energy


References


Footnotes


Citations


Sources

* * * * * * * * *


Further reading

* * *Fox, R, "James Prescott Joule, 1818–1889", in * * * * * * * *


External links

*
The scientific papers of James Prescott Joule (1884)
– annotated by Joule
The joint scientific papers of James Prescott Joule (1887)
– annotated by Joule

''On the Mechanical Equivalent of Heat'' and ''On the Existence of an Equivalent Relation between Heat and the ordinary Forms of Mechanical Power''
Joule's water friction apparatus
at London Science Museum *
Some Remarks on Heat and the Constitution of Elastic Fluids
', Joule's 1851 estimate of the speed of a gas molecule
Joule Manuscripts
at John Rylands Library, Manchester.
University of Manchester material on Joule
– includes photographs of Joule's house and gravesite
Joule Physics Laboratory
at the University of Salford {{DEFAULTSORT:Joule, James Prescott James Prescott Joule, 1818 births 1889 deaths 19th-century British physicists English physicists Fellows of the American Academy of Arts and Sciences Fellows of the Royal Society Foreign associates of the National Academy of Sciences Fluid dynamicists History of Greater Manchester People associated with electricity People associated with energy People from Salford Recipients of the Copley Medal Royal Medal winners Thermodynamicists Manchester Literary and Philosophical Society