James Prescott Joule (Physicist) - Pics, Videos, Dating, & News James Prescott Joule Male Born Dec 24, 1818 James Prescott Joule FRS was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work. This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him.… Read More related links Learn about the memorable moments in the evolution of James Prescott Joule. CHILDHOOD 1818 Birth Born on December 24, 1818. TWENTIES 1840 21 Years Old 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 engines with the newly invented electric motor. … Read More His first scientific papers on the subject were contributed to William Sturgeon's Annals of Electricity.

Read Less 1841 22 Years Old Motivated in part by a businessman's desire to quantify the 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 in 1841, that the heat which is evolved by the proper action of any voltaic current is proportional to the square of the intensity of that current, multiplied by the resistance to conduction which it experiences. … Read More He went on to realize that burning a pound of coal in a steam engine was more economical than a costly pound of zinc consumed in an electric battery. Joule captured the output of the alternative methods in terms of a common standard, the ability to raise one pound, a height of one foot, the foot-pound. Read Less Show Less In June 1845, Joule read his paper On the Mechanical Equivalent of Heat to the British Association meeting in Cambridge. … Read More 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 in an insulated barrel of water which increased the temperature.

He now estimated a mechanical equivalent of 819 ftÂ·lbf/Btu (4.41 J/cal). Read Less He wrote a letter to the Philosophical Magazine, published in September 1845 describing his experiment. … Read More In 1850, Joule published a refined measurement of 772.692 ftÂ·lbf/Btu (4.159 J/cal), closer to twentieth century estimates.<br /><br /> Much of the initial resistance to Joule's work stemmed from its dependence upon extremely precise measurements. 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-maker John Benjamin Dancer.

Joule's experiments complemented the theoretical work of Rudolf Clausius, who is considered by some to be the coinventor of the energy concept.<br /><br /> Joule was proposing a kinetic theory of heat (he believed it to be a form of rotational, rather than translational, kinetic energy), 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. We should also remember that the very existence of atoms and molecules was not widely accepted for another 50 years. Read Less 1847 28 Years Old Also in 1847, another of Joule's presentations at the British Association in Oxford was attended by George Gabriel Stokes, Michael Faraday, and the precocious and maverick William Thomson, later to become Lord Kelvin, who had just been appointed professor of natural philosophy at the University of Glasgow. … Read More Stokes was "inclined to be a Joulite" and Faraday was "much struck with it" though he harboured doubts.

Thomson was intrigued but sceptical.<br /><br /> Unanticipated, Thomson and Joule met later that year in 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. Read Less 1848 29 Years Old 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, Thomson wrote that "the conversion of heat (or caloric) into mechanical effect is probably impossible, certainly undiscovered" â but a footnote signalled his first doubts about the caloric theory, referring to Joule's "very remarkable discoveries". … Read More 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. Read Less THIRTIES 1851 32 Years Old 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". … Read More 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. Read Less 1852 33 Years Old The collaboration lasted from 1852 to 1856, its discoveries including the Joule-Thomson effect, and the published results did much to bring about general acceptance of Joule's work and the kinetic theory. … Read More 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, 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 on the kinetic theory of gases. He was further profoundly influenced by Peter Ewart's 1813 paper On the measure of moving force.<br /><br /> 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.<br /><br /> Joule could not resist finding antecedents of his views in Francis Bacon, Sir Isaac Newton, John Locke, Benjamin Thompson (Count Rumford) and Sir Humphry Davy. Though such views are justified, Joule went on to estimate a value for the mechanical equivalent of heat of 1034 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 than Rumford's, perhaps in the hope that Mayer had not anticipated his own work. Read Less FIFTIES 1869 50 Years Old Joule has been attributed with explaining the Green Flash phenomenon in a letter to the Manchester Literary and Philosophical Society in 1869: actually, he just noted (with a sketch) the last glimpse as bluish green. 1878 59 Years Old Joule died at home in Sale and is buried in Brooklands cemetery there. The 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 of work must be expended at sea level to raise the temperature of one pound of water from 60 to 61 F. There is also a quotation from the Gospel of John, "I must work the works of him that sent me, while it is day: the night cometh, when no man can work" (9:4).

… Read More The Wetherspoon's public house in Sale, the town of his death, is named after him "The J. P. Joule". The family brewery still lives on but now located in Market Drayton (see joulesbrewery.co.uk for more information on origins). Read Less LATE ADULTHOOD Famous Scientists who have impacted Electrical and Electronic Engineering | School of Electrical & Electronic Engineering School of Electrical & Electronic Engineering Postgrad Order Form Famous Scientists who have impacted Electrical and Electronic Engineering Who are the scientists that gave their names to electrical units such as Volts, Amps, Ohms, Coulombs etc? Who are all these people that we name theorems after in the lectures? In this page we profile some of the famous names that we have in the Electrical and Electronic Engineering discipline. Perhaps there is a role model on this page that you can identify with. Alessandro Guiseppe Antonio Anastasio Volta Alessandro Guiseppe Antonio Anastasio Volta (b. Como, Italy, 18th Feb.1745, d. Como, Italy, 5th March 1827) was a pioneer in the field of electricity.

The SI unit of electric potential was named after him as the Volt. The portrait (above) was featured on the Italian 10,000 Lire banknote. He came from a Lombard family ennobled by the municipality of Como and almost extinguished, in his time, through its service to the church. One of his paternal uncles was a Dominican, another a Canon and the third an Archdeacon. His father, Filipo (1862-1752), after eleven years as a Jesuit, withdrew to propagate the line. Filipo married Maddelena de' conti Inzaghi in 1773. They had seven children; three girls, two of whom became nuns; three boys who followed the careers of their uncles; and Alessandro, the youngest. Alessandro was about seven when his father died. His uncle the Canon took charge of his education. Alessandro joined the local Jesuit College in 1757. His quickness soon attracted the attention of his teachers. In 1761 the philosophy professor, Girolamo Bonensi, tried to recruit him. This made his uncle want to take him from school.

Volta continued his education at Seminario Benzi. His uncle wanted him to be an attorney. But, Volta chose the study of electricity. Alessandro was a large, vigorous man. He actively practised the Catholic faith. He, in the words of his friend Lichtenberg, "understood a lot about the electricity of women." For many years he enjoyed the favours of a singer, Marianna Paris, whom he might have married but for his theological and family opinion. Volta developed the concept of 'state of saturation of bodies' to explain attractions and repulsions of electrified bodies. The electrophore he invented was severely criticized by Beccaria, one of the chief authorities in electricity. In 1774, he became the principal of the state Gymnasium in Como. In 1775, he was granted the professorship of experimental physics. Cavendish's memoir of 1771 made Volta transform his notion of 'natural saturation' into the concept of potential. His last memoir was on galvanic and common electricity. Seeing Volta's demonstrations, Napoleon raised him to Count and Senator of the kingdom of Italy.

During the last 20 years of his life he had the income of a wealthy man. André-Marie Ampére André-Marie Ampére (b. Lyons, France, 22nd Jan. 1775, d. Marseilles, France, 10th June 1836) was a mathematician, a chemist, a physicist and a philosopher. The SI unit of electric current was named after him as the Ampere. His father, Jean-Jacques, was a merchant. Jean-Jacques exposed his son to a library and let him educate himself according to his own tastes. André-Marie soon discovered and perfected his mathematical talents. He even learned Latin in order to read the works by Euler and Bernoulli. The great encyclopédie had the most important influence on him. He was also thoroughly instructed in Catholic faith. During the French Revolution, his father was guillotined. André-Marie was unable to bear this shock. For a year, he retreated, not talking to anyone. During this time, he met Julie Carron who was somewhat older than he was. Ampére pursued Julie until she consented to marry him.

They were wed on the 7th of August 1799 and their son, Jean-Jacques, was born.the following year. Ampére became the professor of physics and chemistry at the École-Centrale of Bourgen-Bresse, where he worked on probability theory. Julie died on the 13th of July 1803 of an illness. Ampére became inconsolable again. He married Jeanne Potot in 1806. After the birth of their daughter, Albine, they got a divorce. Between 1820 and 1825, after a series of experiments, Ampére provided factual evidence for his contention that magnetism was electricity in motion, summarized in his famous 9 points. They describe the law of action of current carrying wires, and model magnets as having circulating currents in them. Ampére was able to unify the fields of electricity and magnetism on a basic numeric level. Fresnel helped Ampére improve his theory by suggesting that there may be currents of electricity around each molecule.

Ampére assumed that the 'electrodynamic molecule' was a molecule of iron that decomposed the aether, that pervaded both space and matter into the two 'electric fluids.' Ampere's theory of the electrodynamic molecule was not accepted by everyone. His primary opponent was Michael Faraday, who could not follow the mathematics and did not accept his theory. Ampére's son fell in love with Mrs. Jeanne Recamier, an entertainer and a great beauty of the empire. His daughter Albine, married an army officer who turned out to be a drunkard. Following this, after 1827, Ampére's scientific activity declined and he died alone, while on a tour in Marseilles. James Prescott Joule James Prescott Joule (b. Salford, England, 24th Dec. 1818, d. Salford, England, 11th October 1889) was the second son of a prosperous brewer. The SI Unit of energy or work was named after him as the Joule. James was not a strong child. He had a spinal injury which left a slight deformity. Because of this, his education was limited.

To a large extent he was self taught. He even read relatively little and had no pretence of being a great scientist. When he was 16, he and his brother, Benjamin, studied under Dalton for about two years. His chief contact with the world was with the members of the Manchester Literary and Philosophical Society. He began his quantitative electrical work when he was 19, using a standard resistance of copper wire. He was a simple, earnest and modest man. He was the first to give an expression for the heat generated in a resistor by current flow, in 1840, and to observe magnetostriction. He spent a major part of his life working on the mechanical equivalence of heat. In 1845, he investigated the relationship between the temperature and the internal energy of gas. In April 1847, he gave a popular lecture in Manchester in which he stated the concept of the conservation of energy. But, it went unnoticed. At a meeting at Oxford in June 1847, he was advised by the chairman to restrict himself to a brief oral report on his experiments, rather than a paper, and not to invite discussion.

Fortunately, his idea was grasped by William Thomson, Faraday and Stokes. Recognition to Joule came from Faraday who introduced Joule's 1849 paper to the Society. This paper won for him the 1852 Royal Medal. His last remarkable contribution was work in 1860 which resulted in a significant improvement of steam-engine efficiency. In the same year, he made one of the first accurate galvanometers and calibrated it by use of a voltmeter. He received many awards and medals including the 1870 Copley Medal and a pension from the queen in 1878. His mother died in 1836. His father retired in 1883 due to illness. James and Benjamin took over the family brewing. James married in 1847 and had a daughter and a son. After the death of his wife in 1854, the brewery was sold. Joule's health became worse as time passed. He suffered from frequent nose-bleeding, presumably haemophilia. But, he kept on working as much as he could until his death. Georg Simon Ohm Georg Simon Ohm (b.

Erlangen, Germany, 16th March 1789, d. Munich, Germany, 6th July 1854) was a mathematician and a physicist. The SI unit of electrical resistance was named after him as the Ohm. His father, Johan Wolfgang Ohm, was a master locksmith. Johan Wolfgang married Maria Elizabeth Beck, daughter of a master tailor. They were a protestant couple. Of their seven children only three survived childhood: Georg Simon the eldest, Martin the mathematician, and Elizabeth Barbara. Johan Wolfgang gave his sons a solid education in mathematics, physics, chemistry and the philosophies of Kant and Fichte. Their mathematical talents were soon recognised by the Erlangen professor Karl Christian Von Langsdorf. Georg Simon matriculated on the 3rd of May 1805 at the University of Erlangen. He studied 3 semesters there until his father's displeasure at his supposed overindulgence in dancing, billiards, and ice skating forced him to withdraw to rural Switzerland. He began to teach mathematics in September 1806 in Gottstadt. He received his PhD on the 25th of October 1811.

Lack of money forced him to seek employment from the German government. But, the best he could obtain was a post as a teacher of mathematics and physics at a poorly attended 'Realschule' in Bamberg. He worked there with great dissatisfaction. In 1817, Ohm was offered the position of 'Oberlehrer' of mathematics and physics at the Jesuit Gymnasium at Cologne. He began his experiments on electricity and magnetism after 1820. His first scientific paper was published in 1825 in which he sought a relationship between the decrease in the force exerted by current-carrying wires and the length of the wires. In April 1826, he published two important papers on galvanicm electricity. He published his book on Ohm's law, Die Galvanische Kette Mathematische Bearbeit, in 1827. Sir John Leslie had already provided both theoretical discussion and experimental confirmation of Ohm's law in a paper written in 1791 and published in 1824, which was not accepted. Ohm's law was so coldly received that Ohm resigned his post at Cologne.

Ohm obtained the professorship of physics at the Polytechninische Schedule in Nuremberg in 1833. Finally, his work began to be recognised. In 1841, he was awarded the Copley Medal of the Royal Society of London and was made a foreign member a year later. Charles William Siemens Charles William Siemens (ne: Carl Wilhelm Siemens, b. Lenthe, Germany, 4th April 1823, d. London, England, 9th November 1883) was a pioneer in the practical application of scientific discoveries to industrial processes. The SI unit of electrical conductance was named after him as the Siemens (S). Christian Ferdinand Siemens, a wealthy farmer, and his wife, Eleonore Deichmann had eleven sons and three daughters, of whom Charles William was the seventh child. In July 1839, Eleonore died. Unable to bear this loss, Ferdinand died six months later. A few years later, the children were dispersed among relations and friends. Siemens went to England in 1843. Being a shrewd businessman, he sold the patent of the electroplating invention of his elder brother, Werner.

William was naturalised as a British subject on the 19th of March 1859. On the 23rd of July he same year, he married Anne Gordon. Siemens Brothers, founded in 1865 by William and Werner, soon became a world famous manufacturer of telegraphic equipment, cables, dynamos and lighting equipment. William was a member of the Society of Telegraph Engineers; the British Association, the Institution of Civil Engineers, and the Institute of Mechanical Engineers and a fellow of the Royal Society. He developed a highly successful meter for measuring water consumption. His important invention of the regenerative gas furnace and its application to open-hearth steel making and other industrial processes made him independently wealthy before 1870. In 1874, he designed the cable ship 'Faraday' and assisted in the laying of the first of several transatlantic cables. During the last 15 years of his life he actively supported the development of the engineering profession and stimulated public interest in the reduction of air pollution and the potential value of electric power in a wide variety of engineering applications. Suffering an acute pain in the region of the heart for a few weeks, he was attacked by a difficulty of breathing.

As he was sitting in his arm chair, peacefully and quietly, as if he were falling asleep, his spirit passed away. The burial took place on the 26th of November, followed by a very grand funeral service. As he had requested, the inscription on his coffin contained simply his name. The Institute of Civil Engineers erected a stained glass window in Westminster Abbey as a tribute of respect in his memory. Charles-Augustin Coulomb Charles-Augustin Coulomb (b. Angouleme, France, 14th June 1736, d. Paris, France, 23rd August, 1806) was a pioneer in the field of electricity, magnetism and applied mechanics. The SI unit of quantity of electric charge was named after him as the Coulomb. In his electrical studies Coulomb determined the quantitative force law, gave the notion of electric mass, and studied charge leakage and the surface distribution of charge on conducting bodies. In magnetism he determined the quantitative force law, created a theory of magnetism based on molecular polarisation, and introduced the idea of demagnetisation. His father, Henrey, came from Montpellier, where the family was important in the legal and administrative history of Languedoc.

His mother, Catherine Bajet, was related to the wealthy de Senac family. During Charles-Augustin's youth the family moved to Paris. Charles-Augustin attended lectures at the College Mazarin and the College de France. An argument with his mother over career plans caused Coulomb to follow his father to Montpellier who became penniless later through financial speculations. Coulomb graduated in November 1761 with the rank of lieutenant en premier in the Corps du Génie. He worked at Brest and then at Martinique. While he was in Martinique he became seriously ill several times. The research he did in Richefort won him the double first prize at the academy in Paris in 1781. He became a resident in Paris. He found a wife there and raised a family. He wrote 25 scientific Momoirs at the Academy from 1781 to 1806. He also participated in 310 committee reports to the Academy. In 1787 Coulomb was sent to England to investigate hospital conditions in London. In 1801 he was elected to the position of the president of the Institute de France.

By 1791, the National Assembly reorganized the Corps du Génie. Coulomb had to resign from the corps. He received an annual pension which was reduced by two-thirds after the Revolution. He returned to his research in Paris in December 1795, upon his election as member for physique experiméntale in the new Institute de France. Coulomb's last public service was as inspector general of public instruction from 1802 until his death. Coulomb's health declined precipitously in the early summer of 1806 and he died. Secondary accounts indicate that Revolution took most of his properties and that he died almost in poverty. Michael Faraday Michael Faraday (b. Newington, Surrey, England, 22nd Sep. 1791, d. Hampton Court, Middlesex, England, 25th August 1867) was a physicist, a chemist, a physical chemist and a natural philosopher. The SI unit of capacitance was named after him as the Farad (F). He was born into a poor family, of which he was he third of four children. His father, James Faraday, was a blacksmith.

James Faraday's poor health prevented him from providing more than bare necessities to his family. Michael later recalled that he was once given a loaf of bread to feed him for a week. His parents were members of the Sandemanian Church, and Michael was brought up within this discipline. His most favourite book was the Bible in which he had heavily underlined, Timothy 6:10, "The love of money is the root of all evil." Michael, at the age of 14, was apprenticed to Riebau, a bookseller and a bookbinder, in whose shop he read books on science that came to his hands. In 1812, one of the customers at Riebau's shop, gave Faraday a ticket to attend the last four lectures of a course given by Humphry Davy at the Royal Institution of Great Britain. He applied to Davy for employment, sending him as evidence of his interest the notes that he had made of his lectures. At the age of 21, he was appointed assistance to Davy to help with both lecture experiments and research. He accompanied Davy on a tour in Europe where he saw much of the active scientific research.

In 1821, he married Sarah Barnard, a union that was happy though childless. Faraday became the discoverer of electromagnetic induction, of the laws of electrolysis, and of the fundamental relations between between light and magnetism. He was the originator of the conceptions that underlie the modern theory of the electromagnetic field. He also discovered two unknown chlorides of carbon and a new compound of carbon. His last discovery was the rotation of the plane of polarization of light in magnetic field. When Faraday was endeavouring to explain to the Prime Minister or to the Chancellor of the Exchequer an important discovery, a politician's alleged comment was, "But, after all, what use is it?" Whereupon Faraday replied, "Why sir, there is a probability that you will soon be able to tax it!" His mind deteriorated rapidly after the mid-1850s. In 1862, he resigned his position at the Royal Institution, retiring to a house provided for him by Queen Victoria at Hampton Court. Joseph Henry Joseph Henry (b. Albany, NY, USA, 17th December 1797, d.

Washington, USA, 13th May 1878) was a pioneer in the field of electromagnetism. The SI unit of inductance was named after him as the Henry (H). He was born to a poor family of Scottish descent and raised as a Presbyterian, a faith he followed throughout his life. His elementary education was in Albany and Galway, New York, where he stayed with relatives. Henry was apprenticed to an Albany watchmaker and silversmith. The theater was his principal interest as an adolescent, until a chance reading of George Gregory's Popular Lectures on Experimental Philosophy, Astronomy, and chemistry turned him to science. In 1819 he enrolled in the Albany Academy and remained there until 1822, with a year off to teach in a rural school in order to support himself. He did odd surviving jobs while he was doing his scientific research. in 1825, Henry was appointed professor of mathematics and natural philosophy at the Albany Academy. In 1832, he accepted a chair at the College of New Jersey. Henry's earliest known work was in chemistry. In 1827, he started active research on electricity and magnetism.

Throughout his career, Henry was interested in terrestrial magnetism and other geophysical topics. He independently uncovered the sense of Ohm's law and engaged in impedance matching. In 1832, Henry discovered self-inductance following some experiments. He also conducted investigations on capillarity, phosphorescence, heat, colour blindness and the relative radiation of solar spots with skill and imagination. His 1835 paper was on the action of a spiral conductor in increasing the intensity of galvanic currents. He conceived of astronomy as the model science and mechanics as the ultimate analytical tool. Henry could not accept Faraday's field concept because of his belief in central forces acting in a universal fluid. He concluded that the currents are oscillatory wave phenomena exciting equivalent effects in an electrical plenum coincident, if not identical, with the universal aether. Henry formed the Smithsonian Committee, consisting of dedicated men forming internationally recognized standards and engaging in free and harmonious intellectual intercourse among themselves. Being the secretary of the Smithsonian, he was not interested in popularizing science but with supporting research and disseminating findings. Nicola Tesla Nicola Tesla (b. Smiljan, Croatia, 10th July 1856, d.

New York 7th Jan. 1943) was a pioneer in the field of high-tension electricity. The SI unit of magnetic flux density was named after him as the Tesla (T). He made many discoveries and inventions of great value to the development of radio transmission and to the field of electricity. These include a system of arc lighting, the Tesla induction motor and a system of alternating-current transmission, the Tesla coil, a transformer to increase oscillating currents to high potential, a system of wireless communication, and a system of transmitting electric power without wires. He designed the great power system at Niagara. Tesla's advanced concepts include transmission of large quantities of electrical power without wires and inexhaustible energy supplies from the universe. Despite over 700 patents bearing his name he disliked being called an "inventor," much preferring the description "discoverer." He emigrated to United States in 1884 with the hope of finding a backer for his polyphase alternating current system. The magnet that drew him was the Niagara falls. As a boy in his teens he had seen a picture of the falls, ever since then the hope of converting the power of the falls into electricity had remained with him.

It is said that when he thought of an object, he could see it physically and had no need of pencil and paper, just as when he read, which he did rapidly, he was virtually photographic. When Edison heard his ideas he was not interested but gave him a job. Edison promised $50,000 if Tesla could perfect a new type of dynamo. When Tesla succeeded and asked for the money he was told that he did not understand American sense of humour. At this point Tesla quit. He was unemployed and was forced to dig ditches at $2 per day to earn a living. Fortunately his foreman introduced him to a Mr Brown of Westinghouse and once more he had a laboratory. Tesla continued on his invention and in May 1890, he was granted the first string of patents, and they grew faster. George Westinghouse offered one million dollars to Tesla for his patents. During the Spanish -American war Tesla offered to the government his invention of a "robot" to be operated by remote control by means of his wireless system. They laughed at him. He died a pauper leaving behind a golden legacy in the shape of his great inventions. Wilhelm Eduard Weber Wilhelm Eduard Weber (b.

Wittenberg, Germany, 24th October 1804, d. Gottingen, Germany, 23rd June 1891) was one of the twelve children of Michael Weber, professor of theology at the University of Wittenberg. The family lived in the house of Christian August Langguth, a professor of medicine and natural history. The house was burned during the bombardment of Wittenberg by the Prussians in 1813. The following year the Webers settled in Halle. Wilhelm began his scientific work in collaboration with Ernest Heinrich at the University of Halle. Wilhelm published his famous paper, which contained experimental investigations of water and sound waves, in 1825. In 1831, he became the professor of physics at Gottingen, where his friendship with Gauss began. In 1832, Weber introduced absolute units of measurements into magnetism. Gauss and Weber founded the Gottingen Magnetische Verenin to initiate a network of magnetic observations and to correlate the resulting measurements.

In 1833, they set up a battery-operated telegraph line some 9,000 feet long, between the physics and astronomical observatory, in order to facilitate simultaneous magnetic observations. Weber also managed to find time to work with his younger brother Eduard on the physiology and physics of human locomotion. With the death of William IV in 1837, Victoria became the queen of England and her uncle, Ernst August, acceded to the rule of Hannover and at once revoked the liberal constitution of 1833. Weber was one of the seven Gottingen professors who signed a statement of protest. At the king's order all the seven lost their positions. But, Weber continued his research. In 1843, Weber became the professor of physics at Leipzig. There he formulated his law of electrical force, which was later discarded with the triumph of Maxwell's field theory. In 1848, he was able to return to his old position. Weber retired in 1870's, relinquishing his duties in physics to his assistant, Edward Rieche. Rieche, later began the development of electron theory of metals from Weber's ideas.

Weber received many honours from Germany, France, and England, including the title of Geheimrat and the Royal Society's Copley Medal. The SI unit of magnetic flux was named after him as the Weber (Wb). Weber, a friendly, modest, and unsophisticated man, remained unmarried. He died peacefully in his garden. Heinrich Rudolf Hertz Heinrich Rudolf Hertz (b. Hamburg, Germany, 22nd Feb. 1857, d. Bonn, Germany, 1st January 1894), a physicist, whose research has come to be regarded as the starting point of radio - it was he who first detected and measured electromagnetic waves in space. The SI unit of frequency was named after him as the Hertz (Hz). His grandfather, Heinrich David Hertz, the youngest son of a wealthy Jewish family was converted to the Lutheran faith along with his wife and children. David Heinrich Hertz's son, Gustav, became a Minister of Justice and was the first to attend a university in the family.

He married a classmate's sister, Anna Elisabeth Pfefferkorn, and had five children, the eldest of whom was Heinrich Rudolf Hertz. He was an exceptionally gifted child and excelled in every way. After completing his secondary education, he wanted to be a structural engineer and served as an apprentice in a civil engineering office. Reading a lot of books, he became interested in telegraphy and enrolled in the Technical University of Dresden. Finding the level of instruction low for him, after one semester, he embarked on his year of compulsory military service. He then enrolled in the Technical University of Munich to do physics, but later, switched to the University of Munich. He was still not satisfied, and after two semesters transferred to the University of Berlin where Gustav Kirchhoff and Hermann Helmholtz taught physics. Very soon he was working as a student assistant to Helmholtz. He graduated the following year, before which he had written two papers on his research - determining if electrons have inertial mass and induction in rotating spheres. He obtained his doctorate in 1880 and was appointed assistant of Helmholtz.

After three years, he went to the University of Kiel to become a lecturer in physics and soon he was promoted and became a professor at the Technical High School in Karlsruhe, and then he went to the University of Bonn. In 1886 he married Elizabeth Doll, and started his research on electric waves. He wrote many papers not only in electromagnetism but also in the theory of contact mechanics and the measurement of hardness. Suffering a severe illness which led to chronic blood poisoning he died after indescribable suffering. He was an extremely modest man and once denying the request for publishing his portrait he said, "... Too much honour certainly does me harm in the eyes of reasonable men..." and four years after, following his death, his portrait was published. Guglielmo Marconi Guglielmo Marconi (b. Bologna, Italy, 25th April 1874, d. Rome, Italy, 20th July, 1937) was the second son of Giuseppe Marconi, a wealthy landowner, and his second wife, Annie Jameson, the daughter of an Irish Whiskey distiller.

Giuseppe Marconi ruled his household in the style of a martinet. Guglielmo spent most of childhood away from home. Consequently, his education was neglected. When he was sent to a school, he was unable to cope with his studies and other students made fun of his poor Italian accent. He failed to pass the entrance examination to the Italian Naval Academy and went to Livorno Technical Institute. His ambition was to have an electrical career, but he could not even pass his matriculation. His father became very angry, wrecked the devices Guglielmo had constructed, and even withheld his pocket money. But, his mother did all she could to help her son do his experiments. Marconi did experiments on electromagnetic waves with the assistance of Prof. A. Righi of Bologna and discovered that increased transmission distance could be obtained with larger antennas. In 1895, he achieved a transmission distance of 1.5 miles, and also conceived of 'wireless telegraph' communication. Being unable to interest the Italian Government in the potential of his work, he moved to London in 1896. His Irish cousin, Henry Jameson Davis, helped him to form and finance the Wireless Telegraph and Signal Co.

Ltd., which became Marconi's Wireless Telegraph Co. Ltd. in 1900. On behalf of the Italian Government, Solari presented to Marconi a newly invented receiver. Having increased his signaling distance to 150 miles, using a kiteborne antenna and Solari's carbon-on-steel detector with a telephone receiver, on the 12th of December 1901, he received a transatlantic wireless communication, the three code dots signifying the letter 'S'. He became famous overnight. But, controversy arose when Prof. Angelo Banti pointed out that the receiver was actually invented by a corporal signalman, Paolo Castelli. After 1902, Marconi spent most of his time managing his companies. He was able to attract highly qualified employees including J. A. Fleming. In 1927, Marconi's company completed a system of shortwave beam stations. In 1932, he discovered that microwaves could be received at a point much farther below the optical horizon than had been predicted by any theory. Marconi received many awards including the Nobel Prize for physics, which he shared with K. F. Braun in 1909.

Gustav Robert Kirchhoff Gustav Robert Kirchhoff (b. Konigsberg, Germany, 12th March 1824, d. Berlin, Germany, 17th October 1887) was a physicist. His father was a law councillor. Kirchhoff easily derived Kirchhoff's voltage law for electrical network analysis between 1845-1846, while he was still a student at Konigsberg. In 1849, following the experiments of Kohlrausch, he introduced Kirchhoff's current law for electrical network analysis. He graduated in 1847 and married Clara Richelot, the daughter of one of his teachers, the same year. Three years later, he was appointed professor at Breslau. In 1854, he moved to Heidelberg, where Robert Bunsen was a professor of chemistry. In 1869, Clara died, leaving him two sons and two daughters. In 1872, he married Luise Brommel. In 1859, he published an explanation of the dark lines in the sun's spectrum, discovered by Josef von Fraunhofer.

In the course of investigating the optical spectra of chemical elements, Kirchhoff made his major contribution to science which was his experimental discovery and theoretical analysis of a fundamental law of electromagnetic radiation which states that for all material bodies, the ratio of absorptive and emissive power of radiation is a universal function of wavelength and temperature. In 1860, Bunsen and Kirchhoff discovered that each chemical substance emits light that has its own unique pattern of spectral lines. A Few months later, they discovered a new metal, cesium and the next year, they found rubidium. They also constructed an improved form of the spectroscope. Kirchhoff once told his bank manager of the discovery of terrestrial metals of the sun. The bank manager said, "Of what use is gold on the sun if I cannot get it down to earth?" later, after Queen Victoria of England had presented Kirchhoff with a medal and a prize in gold sovereigns for work on the sun's spectrum, he took them to the bank manager and said, "Here is some gold from the sun!" Kirchhoff was crippled by an accident in mid-Iife which compelled him to use crutches and wheelchair. But, he remained in good spirit.

On two occasions he turned down calls to other universities. Only when his failing health hindered his experimental work did he accept a chair of theoretical physics offered to him in Berlin. He worked there with great devotion, until illness forced him to give up his teaching activity in 1886. He bore with patience the long illness of his last years. He died peacefully, presumably of a cerebral congestion. Léon Charles Thévenin Léon-Charles Thévenin (b.Meaux, France, 30th March 1857, d. Paris, 1926) was a French telegraph engineer and educator. He was the one to propose the equivalent generator theorem in 1883, 43 years before Norton's complementary theorem. The theorem is commonly called Thévenin's Theorem in his honour, but, in fact Hermann Von Helmholtz proposed it first in an 1853 paper. Thevenin graduated from the École Polytechnique in 1876 and became one of the first students to enrol in the École Superieure de Telegraphie (EST) to be prepared for a career in the Government owned telegraph service.

In the two-year program at the EST, he was introduced to Gustav Kirchhoff's laws of circuit analysis. His duties included administrative and educational activities. Thévenin devoted a considerable portion of his time to teaching, for which he had a liking. In connection with his teaching, he undertook an investigation of Kirchhoff's laws as applied to electric networks. This study resulted in his formulation of the equivalent generator theorem. He was a talented violin player. Another favourite pastime of his was angling. He remained single but shared his home with a widowed cousin of his mother's and her two children whom he later adopted. Thévenin consulted several scholars well known at that time, and controversy arose as to whether his law was consistent with the facts or not. Shortly before his death he was visited by a friend of his, J. B. Pomey, and was surprised to hear that his theorem had been accepted all over the world. In 1926, he was taken to Paris for treatment. He left a formal request that no one should accompany him to the cemetery except his family and that nothing be placed on his coffin but a rose from his garden. This is how he was buried at Meaux.

Thévenin is remembered as a model engineer and employee, hard-working, of scrupulous morality, strict in his principles but kind at heart. It is evident that an acquaintance with natural laws means no less than an acquaintance with the mind of God therein... Died: October 11, 1889 (aged 70) Nationality: English Occupation: Physicist Bio: James Prescott Joule FRS was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work. This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him. James Prescott Joule News | Wiki - UPI.com James Prescott Joule News Today is Monday, Dec. 24, the 358th day of 2001 with seven to follow.

Wiki James Prescott Joule FRS (pronounced /ˈdʒuːl/; 24 December 1818 – 11 October 1889) was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him. He worked with Lord Kelvin to develop the absolute scale of temperature, made observations on magnetostriction, and found the relationship between the current through a resistance and the heat dissipated, now called Joule's law. The son of Benjamin Joule (1784–1858), a wealthy brewer, James Prescott Joule was born in the house adjoining the Joule Brewery in New Bailey Street, Salford on 24th December 1818.

James was tutored at the family home 'Broomhill', Pendlebury, near Salford, until 1834 when he was sent, with his elder brother Benjamin, to study with John Dalton at the Manchester Literary and Philosophical Society. The pair only received two years' education in arithmetic and geometry before Dalton was forced to retire owing to a stroke. However, Dalton's influence made a lasting impression as did that of his associates, chemist William Henry and Manchester engineers Peter Ewart and Eaton Hodgkinson. Joule was subsequently tutored by John Davies. Fascinated by electricity, he and his brother experimented by giving electric shocks to each other and to the family's servants. Joule became a manager of the brewery and took an active role until the sale of the business in 1854. Science was a hobby but he soon started to investigate the feasibility of replacing the brewery's steam engines with the newly invented electric motor. In 1838, his first scientific papers on electricity were contributed to Annals of Electricity, the scientific journal founded and operated by Davies's colleague William Sturgeon.

He formulated Joule's laws in 1840 and hoped to impress the Royal Society but found, not for the last time, that he was perceived as a mere provincial dilettante. When Sturgeon moved to Manchester in 1840, Joule and he became the nucleus of a circle of the city's intellectuals. The pair shared similar sympathies that science and theology could and should be integrated. Joule went on to lecture at Sturgeon's Royal Victoria Gallery of Practical Science. James Prescott Joule - Biography, Facts and Pictures Blog James Prescott Joule James Prescott Joule was an English physicist who studied the nature of heat and established its relationship to mechanical work. He therefore laid the foundation for the theory of conservation of energy, which later influenced the First Law of Thermodynamics. He also formulated the Joule’s laws which deal with the transfer of energy. Advertisements Early Life and Education: Born in Salford, Lancashire on December 24, 1818, James Prescott Joule’s father was a rich brewer. Joule was mostly homeschooled. He studied arithmetic and geometry under John Dalton at the Manchester Literary and Philosophical Society. He was later taught by famous scientist and lecturer, John Davies.

Contributions and Achievements: James Prescott Joule analyzed the nature of heat, and established its relationship to mechanical energy. His efforts had a profound influence on the theory of conversation of energy (the First Law of Thermodynamics). He collaborated with Lord Kelvin on the formulation of the absolute scale of temperature, and carried out extensive research on magnetostriction; a property of ferromagnetic materials that makes them modify their shapes when exposed to a magnetic field. Joule was the first scientist to identify this property in 1842 during an experiment with a sample of nickel. He established the relationship between the flow of current through a resistance and the heat dissipated, which was later termed as Joule’s law. He is also credited with the first-ever calculation the velocity of a gas molecule. The derived unit of energy or work, the Joule, is named after him. Joule was elected to the Royal Society of London and was given a Copley award. He also served as the president of the British Association for the Advancement of Science. Later Life and Death: James Prescott Joule died on October 11, 1889 in Sale, Greater Manchester, England. He was 70 years old.

Advertisements 10 of Science’s Best BAD ideas – Part… John Dalton William Prescott Joule, Physicist William Prescott Joule born in Salford, Lancashire James Prescott Joule, the man James Prescott Joule was born on the 24 December 1818 in New Bailey Street, Salford, Lancashire, and he was Christened at Grosvenor Street (Congregational) Chapel, Manchester, on the 9 February 1819. His parents were Benjamin Joule and Alice Prescott who were married in Wigan, Lancashire, on the 14 May 1814. He was the second of five children and he was a member of a successful brewing family whose antecedents had been Derbyshire farmers for many generations. James was a delicate boy due to a spinal ailment, which left him with a slight but permanent limp. Later in life, he was afflicted by frequent nose bleeding, possibly caused by haemophilia.

James's elder brother was Benjamin St John Baptist Joule who was born on the 8 November 1817 in New Bailey Street, Salford, Lancashire, and he was Christened at Grosvenor Street (Congregational) Chapel, Manchester, on the 24 December 1817. Benjamin, besides being a landowner and Justice of the Peace, was a composer and possibly an author. In 1876 he owned 4,168 acres of land in County Donegal, Ulster. It is understood that he died on the 21 May 1895, aged 77 years, but his death was not recorded in England. As children, private tutors taught James and Benjamin at home where James was particularly interested in scientific toys and he occupied himself among, other things, by flying kites in thunderstorms, in the manner of Benjamin Franklin. He also amused himself by giving family and servants electric shocks. One of James's tutors was the elderly John Dalton, 'the Father of Modern Chemistry', who had been reduced to earning money by teaching the children of wealthy families.

Apparently, James's father was not impressed by John Dalton's tuition but it certainly made a lasting impression on James. In 1847 he married Amelia Grimes, the daughter of the Comptroller of Customs at the Port of Liverpool. Tragically, she died in Salford in 1854 after only seven years of marriage. The couple had two sons and a daughter. Benjamin Arthur was born in 1850, Alice Amelia was born in 1852 and Henry James was born in 1854 but he died shortly afterwards. James was badly shaken by the loss of his wife and son and afterwards he became increasingly retiring. Although he was elected a Fellow of the Royal Society in 1850, he tended to remain remote from this. He also refused to take up a University post. During the last 17 years of his life he suffered from ill health and he died in Sale, Cheshire, on the 11 October 1889, aged 70 years.

James was buried in Brooklands Cemetery, Sale, Cheshire, his gravestone is inscribed with the number 772.55 and a quotation from the Gospel of St John, 'I must work the works of Him that sent me, while it is day: the night cometh, when no man can work' (9:4). Apparently, the number 772.55 was a value for the mechanical equivalent of heat that he obtained in 1878. There is also a statue of him in Manchester Town Hall. James Prescott Joule. James Prescott Joule, the physicist When aged 15 years, Joule began work in his father's brewery where he took a keen interest in both engineering and chemistry. In those days, a brewery was the perfect place for him to study machinery, such as engines and pumps that handled large quantities of liquids, and chemical processes, such as fermentation. Five years later he created a laboratory in the cellar of his parents' home and he began to attend the meetings of the Manchester Literary and Philosophical Society, where he met famous scientists and engineers of the day.

He flourished in the academic surroundings of the Society and he may never have formulated his principle of the conservation of energy had he been educated at one of the country's universities because these were still governed by Newtonian mechanics. Joule is best known for his determination of the mechanical equivalent of heat, for which he received honours, and, more recently, the honour of having his surname adopted as the Système International d'Unités (SI) unit of energy. The SI is the modern form of the metric system, finally agreed in 1960 by the supreme international authority on units of measurement, the General Conference of Weights and Measures (CGPM). Thus the SI supplementary unit of energy, work and quantity of heat is the joule, unit symbol J, this being the equivalent of one Newton metre (N m). In Joule's day the imperial system of measurement of physical units was the foot-pound-second (FPS) system.

This progressed through the centimetre-gram-second (CGS) system to the metre-kilogram-second (MKS) system before being replaced by the SI system that uses the three base units of the MKS system plus the ampere (electric current), mole (amount of substance), candela (luminous intensity) and kelvin (thermodynamic temperature). To prove his theory that it was possible to convert mechanical work directly into heat Joule demonstrated in 1845, with the aid of a paddle-wheel that involved the paddle being driven in water by a falling weight suspended from a pulley, that the amount of work done always produced the same amount of heat. This enabled Joule to conclude that heat was a form of energy. After a number experiments he eventually concluded that 781.8 ft lb of work was needed to raise the temperature of one pound of water by one degree Fahrenheit. The order of magnitude of his results was considered by Joule to be compelling evidence of the convertibility of work into heat. Hence Joule had determined the amount of mechanical work needed to produce an equivalent amount of heat, this quantity being known as 'the mechanical equivalent of heat'.

Nowadays, working in the original FPS system, it is known that the temperature of one pound of water is increased by one degree Fahrenheit when a weight of 777.65 lb falls from an altitude of one foot (or a weight of 1 lb falls through a height of 777.65 ft and so on). In the modern SI system, the energy needed to raise the temperature of 1 kg of water by one degree kelvin is 4,184 J kg-1 K-1 and this is called the specific heat capacity of water. By these experiments, Joule had discovered what became known as the First Law of Thermodynamics. This law of equivalence of heat and work may be stated as follows: Heat and work are mutually convertible and in any action involving such conversion a definite quantity of heat is lost for every unit of work done and, conversely, a definite quantity of mechanical energy is used for every unit of heat gained. The relationship between work and heat is sometimes known as Joule's equivalent of heat.

Assuming 100% efficiency: Heat absorbed by a material (J) = mass of material (kg) x specific heat capacity of the material (J kg-1 K-1) x temperature rise (K) The First Law of Thermodynamics is the law of conservation of energy, where energy is the capacity to do work. 'Energy can neither be created or destroyed' Another way of expressing the First Law of Thermodynamics is: The internal energy of a body (such as a fluid) can be increased by heating it and/or doing mechanical work on it. In symbols: ΔE = Q + W, where E is the internal energy of the body, Q is the thermal energy, W is the work done (mechanical energy) and Δ is a finite increment in the variable E. In 1840 Joule experimented on the power needed to drive electric motors and the heating effect of an electric current. He determined that the heat produced in a wire by an electric current is proportional to the square of the current multiplied by the resistance of the wire. Hence: P = I2 R, where P is the power in watts, I is the current in amperes and R is the electrical resistance in ohms.

This relationship is known as Joule's Law. Joule experimented with electric welding and also made the first mercury displacement vacuum pump. He proposed the constant pressure cycle for gas engines (Joule Cycle), which he said could run at much higher temperatures than steam engines and thus be more efficient. This cycle, now with the name 'Brayton Cycle', is used for gas turbines. He also had an idea to change the power source of the family brewing business from steam power to electric power, the motors being supplied with electricity from batteries. Unfortunately, this idea was ahead of the technology of the day and the cost of zinc used in the manufacture of batteries was prohibitive. In his day it was still cheaper to produce steam for power by burning coal. His papers on physics were apparently read to fellow members of the Manchester Literary and Philosophical Society at St Ann's Reading Room in Manchester, although the Society had purpose-built premises at 36 George Street, which it occupied until the building was completely destroyed in the Christmas 1940 blitz. In May 1847 he read his paper, 'On Matter, Living Force and Heat'.

In this lecture he was able to give a more accurate figure for the mechanical equivalent of heat and this was 781.8 ft lb to raise the temperature of water by one degree Fahrenheit. In 1849 he read his memoir, 'On the Mechanical equivalent of Heat'. In this he stated, 'In accordance with the pledge I gave to the Royal Society some years ago, I have now the honour to present it with the results of the experiments I have made in order to determine the mechanical equivalent of heat with exactness.' In 1882, Lord Kelvin said of him, 'His boldness in making such large conclusions from such small observational effects is almost as noteworthy and admirable as his skill in extorting accuracy from them.' An amusing incident in Joule's life was to conduct a scientific experiment while on honeymoon in the Alps. He had always wanted to show that when water falls through 778 feet that its temperature rises by one degree Fahrenheit. His chance to do try this experiment came when the couple visited the falls at Chamonix. Armed with a large thermometer, he attempted to measure the rise in temperature at the bottom of the falls but he was thwarted in his attempt.

The water did not fall through 778 feet and too much spray was produced to allow his experiment to work. Joule was elected a fellow of the Royal Society in 1850 and his public honours included degrees from Dublin, Oxford and Edinburgh. He was awarded the Royal Medal of the Royal Society in 1852. In 1860 he was elected President of the Manchester Literary and Philosophical Society. In 1872 he was President of the British Association. Census Returns for 1851, 1871 & 1881 1851 Census James Prescott Joule Quotes - iz Quotes Died: October 11, 1889 (aged 70) Nationality: English Occupation: Physicist Bio: James Prescott Joule FRS was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work. This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him.

This Month in Physics History This Month in Physics History June 1849: James Prescott Joule and the Mechanical Equivalent of Heat By Richard Williams Image: wikimedia commons Engraving of Joule's apparatus for measuring the mechanical equivalent of heat, in which the energy from the falling weight on the right is converted into heat at the left, through stirring of water. Photo: wikimedia commons James Prescott Joule During the mid-1800s, many scientists accepted the caloric theory of heat, which considered heat to be a fluid that could neither be created nor destroyed and which flowed from warm bodies to cold ones. But an obscure home-schooled brewer’s son in the north of England, James Prescott Joule, was impressed by the celebrated cannon-boring experiments of Count Rumford, which showed that heat could be created continuously by the mechanical work of boring a cannon. He recognized that Rumford’s discovery needed to be quantified by an experimental determination of the mechanical equivalent of heat. Thus, this unlikely physicist, who had never had adult instruction or a single course in physics, began his careful experiments that would change the physics of energy.

These experiments became the foundation of the First Law of Thermodynamics, the principle of conservation of energy, and the support of much of the energy technology of modern life. Joule was born in 1818 in Salford, England, near where his family operated a brewery in Manchester. Working there in what was considered the scientific hinterland during much of his career, Joule was long ignored by the scientific establishment. He did not have formal schooling, but received some tutoring from scientist John Dalton, pioneer of the theory of atomic weights and the composition of molecules. As an adult Joule became the manager of the family business; he worked a full day making beer and then pursued his scientific investigations at the end of the day, as an avocation. [ 1 ] He investigated the heat generated by many mechanical actions, including the stirring of water by a paddle, expansion of a gas into a vacuum, and the generation of heat by current flow in electrically conducting materials. The experiment that showed most directly the connection between mechanical action and heat involved the stirring of water by a paddle. He gave an extensive summary of this work in a report [ 2 ] to the Royal Society of London in June, 1849.

In one design, the paddles, immersed in water, were mounted on a vertical shaft, rotated by a cord propelled by falling weights. The temperature increase of the water was of order one degree centigrade. The experiment required very careful control of the ambient conditions and corrections for extraneous heat flow. Some scientists were skeptical whether the experiments could be accurate enough, but, in the end, Joule’s work stood the test of time and was confirmed by others. Combined with the results of other researchers, Joule’s determination of the mechanical equivalent of heat led to the First Law of Thermodynamics. The law, based on the idea of the conservation of energy, states that for a process in a defined system, the change in internal energy is equal to the amount of heat absorbed minus the work done. Joule recognized that, in a container that cannot exchange heat with the surroundings, if a gas is compressed, and then allowed to expand into a vacuum, the expanding gas does no work. Therefore, according to the First Law, the energy of an ideal gas would not change, nor would its temperature. His experiments showed this to be the case. However, small temperature changes do occur that were too small to be detected in his experiments.

This work came to the attention of Lord Kelvin, who joined Joule in a more sensitive experiment involving expansion of the gas through a porous plug. This experiment showed significant temperature changes that depended on the initial temperature and pressure. Later, these changes were understood to be due to the force between molecules. This was the Joule-Thomson experiment. When it was fully understood, it enabled the liquefaction of what were known as “permanent gases.” Liquefaction of gases is the basis of today’s multibillion-dollar industries of air conditioning and cryogenics. By measuring current flow versus resistance in various materials, Joule established the P = I2R relation between resistance, current flow, and the rate of heat generated. This was not as easy as it looks today. Owing to the work of Georg Ohm, the concept of electrical resistance was just emerging, and electrical current was still a controversial idea. But, again, Joule was right about the physics before a consensus emerged. Down to our own time, electrical heating by current flow in a resistor has been both a bane and a bounty.

Resistive heating improves daily life in our stoves, furnaces, irons, and other household conveniences, and underlies a multitude of industrial operations. At the same time, it steals power on the way from generating stations to users, and damages electronic circuits and electric motors. We can deal better with both bane and bounty because Joule quantified the physics. After years of being ignored in his early life, he was finally honored by the scientific community in England and named to the presidency of the Literary and Philosophical Society. His honors spread to Europe and far beyond. “A crater on the moon has been named after him and a French submarine was named Joule; sadly, she was lost with her crew in the Dardanelles in 1915” [ 3 ]. More than one hundred fifty years after the work was done, his name lives on in the physics community around the world. His initial, J, is the symbol for the unit of energy in the SI system. The P = I2R relation is known as Joule’s Law. Joule passed away in 1889 at his home not far from his birthplace.

An epitaph for another gentleman-scientist, Benjamin Franklin, said “He seized the lightning from the sky and the scepter from tyrants.” When James Prescott Joule bypassed the caloric theory and determined the mechanical equivalent of heat, it could be said that “He seized the heat from darkness and the work from isolation.” References 1. D.S.L. Cardwell, James Joule, A Biography, Manchester University Press, 1989. 2. J.P. Joule, On the Mechanical Equivalent of Heat, Philosophical Transactions of the Royal Society of London 140 (1850): 61-82. 3. D.S.L. Cardwell, op. cit. The author is a regular contributor to This Month in Physics History. ©1995 - 2017, AMERICAN PHYSICAL SOCIETY APS encourages the redistribution of the materials included in this newspaper provided that attribution to the source is noted and the materials are not truncated or changed. Editor: David Voss Contributing Correspondent: Alaina G. Levine Art Director and Special Publications Manager: Kerry G.

Johnson Publication Designer and Production: Nancy Bennett-Karasik James Prescott Joule (Author of Scientific Papers) edit data James Prescott Joule FRS (/dʒuːl/; (24 December 1818 – 11 October 1889) was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the Law of conservation of energy, and this led to the development of the First law of thermodynamics. The SI derived unit of energy, the joule, is named for James Joule. He worked with Lord Kelvin to develop the absolute scale of temperature. Joule also made observations of magnetostriction, and he found the relationship between the current through a resistor and the heat dissipated, which is now called Joule's first law. A bust of him, by John Cassidy, can be found in Worthington Park, Sale.

Fur James Prescott Joule FRS (/dʒuːl/; (24 December 1818 – 11 October 1889) was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the Law of conservation of energy, and this led to the development of the First law of thermodynamics. The SI derived unit of energy, the joule, is named for James Joule. He worked with Lord Kelvin to develop the absolute scale of temperature. Joule also made observations of magnetostriction, and he found the relationship between the current through a resistor and the heat dissipated, which is now called Joule's first law. A bust of him, by John Cassidy, can be found in Worthington Park, Sale. Further details of this work can be found at .

Fellow of the Royal Society, (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, (1860); President of the British Association for the Advancement of Science, (1872, 1887); Honorary Membership of the Institution of Engineers and Shipbuilders in Scotland, (1857); Honorary degrees: DCL, University of Oxford, (1860); LL.D., University of Edinburgh, (1871). He received a civil list pension of £200 per annum in 1878 for services to science; 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 by Alfred Gilbert, stands in Manchester Town Hall, opposite that of Dalton. ...more

Question: Which Salford born physicist and brewer, who has an SI unit named after him, lived from 1818 to 1889?
Answer: JAMES JOULE