Current through a resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840.

Joule studied this phenomenon in the 1840s.

It was first studied by James Prescott Joule in 1841.

This type of expansion is named after James Prescott Joule who used this expansion, in 1845, in his study for the mechanical equivalent of heat, but this expansion was known long before Joule e. g. by John Leslie, in the beginning of the 19th century, and studied by Joseph-Louis Gay-Lussac in 1807 with similar results as obtained by Joule.

Though in 1847 he published a paper in Liebig's Annalen der Chemie on the ' Mercaptan of Selenium ,' his mind was busy with the new ideas upon the nature of heat which were promulgated by Carnot, Clapeyron, Joule, Clausius, Mayer, Thomson, and Rankine.

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

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

Pierre Perrot claims that the term thermodynamics was coined by James Joule in 1858 to designate the science of relations between heat and power.

* James Joule experimentally finds the mechanical equivalent of heat.

In 1847, the English physicist James Joule showed that he could raise the temperature of water by turning a paddle wheel in it, thus showing that heat and mechanical work were equivalent or proportional to each other, i. e., approximately,.

* 1843 – James Joule experimentally finds the mechanical equivalent of heat

The theorem was originally misunderstood ( notably by Joule ) to imply that a system consisting of an electric motor driven by a battery could not be more than 50 % efficient since, when the impedances were matched, the power lost as heat in the battery would always be equal to the power delivered to the motor.

Lavoisier's prestige and the practical success of Sadi Carnot's caloric theory of the heat engine since 1824 ensured that the young Joule, working outside either academia or the engineering profession, had a difficult road ahead.

Further experiments and measurements by Joule led him to estimate the mechanical equivalent of heat as 838 ft · lbf of work to raise the temperature of a pound of water by one degree Fahrenheit.

Joule was undaunted and started to seek a purely mechanical demonstration of the conversion of work into heat.

The fact that the values obtained both by electrical and purely mechanical means were in agreement to at least one order of magnitude was, to Joule, compelling evidence of the reality of the convertibility of work into heat.

In 1845, Joule read his paper On the mechanical equivalent of heat to the British Association meeting in Cambridge.

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.

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 ".

Joule perceived the relationship between his discoveries and the kinetic theory of heat.

Though such views are justified, Joule went on to estimate a value for the mechanical equivalent of heat of 1034 foot-pound

In thermodynamics, the Joule – Thomson effect or Joule – Kelvin effect or Kelvin – Joule effect or Joule – Thomson expansion describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment.

The effect is named for James Prescott Joule and William Thomson, 1st Baron Kelvin who discovered it in 1852 following earlier work by Joule on Joule expansion, in which a gas undergoes free expansion in a vacuum.

Joule's first law is sometimes called the Joule – Lenz law since it was later independently discovered by Heinrich Lenz.

Examples include Michael Faraday, who, with James Clerk Maxwell, unified the electric and magnetic forces in what are now known as Maxwell's equations ; James Joule, who worked extensively in thermodynamics and is often credited with the discovery of the principle of conservation of energy ; Paul Dirac, one of the pioneers of quantum mechanics ; naturalist Charles Darwin, author of On the Origin of Species and discoverer of the principle of evolution by natural selection ; Harold Kroto, the discoverer of buckminsterfullerene ; William Thomson ( Baron Kelvin ) who drew important conclusions in the field of thermodynamics and invented the Kelvin scale of absolute zero ; botanist Robert Brown discovered the random movement of particles suspended in a fluid ( Brownian motion ); and the creator of Bell's Theorem, John Stewart Bell.

Besides the law named in his honor, Lenz also independently discovered Joule's law in 1842 ; to honor his efforts on the problem, it is also given the name the " Joule – Lenz law ," named also for James Prescott Joule.

The equivalence between lost mechanical energy and an increase in temperature was discovered by James Prescott Joule.

A dc bias current is applied to the resistor to raise its temperature via Joule heating, such that the resistance is matched to the waveguide characteristic impedance.

The main parameter affecting varistor life expectancy is its energy ( Joule ) rating.

Joule heating is referred to as ohmic heating or resistive heating because of its relationship to Ohm's Law.

These are sometimes used in conjunction with Joule heating ( also called self-heating in this context ): If a large current is running through the resistor, the resistor's temperature rises and therefore its resistance changes.

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

In 1861, a committee of the British Association for Advancement of Science ( BAAS ) including William Thomson ( later Lord Kelvin ), James Clerk Maxwell and Joule among its members was tasked with investigating the " Standards of Electrical Resistance ".

Joule's first law, also known as the Joule effect, is a physical law expressing the relationship between the heat generated by the current flowing through a conductor.

There is an intimate relationship between Johnson – Nyquist noise and Joule heating, explained by the fluctuation-dissipation theorem.

Thomson's close relationship with Joule allowed him to become dragged into the controversy.

The constant of proportionality is universal and independent of the system and was measured by James Joule in 1845 and 1847, who described it as the mechanical equivalent of heat.

::-James Prescott Joule experimentally finds the mechanical equivalent of heat.

The idea of heat death was first proposed in loose terms beginning in 1851 by William Thomson, 1st Baron Kelvin, who theorized further on the mechanical energy loss views of Sadi Carnot ( 1824 ), James Joule ( 1843 ), and Rudolf Clausius ( 1850 ).

* James Prescott Joule experimentally finds the mechanical equivalent of heat.

His achievements were overlooked and priority for the discovery of the mechanical equivalent of heat was attributed to James Joule in the following year.

* 1843 – James Prescott Joule measures the equivalence between mechanical work and heat, resulting in the law of conservation of energy

In 1798, Thompson demonstrated the conversion of mechanical work into heat, and in 1847 Joule stated the law of conservation of energy, in the form of heat as well as mechanical energy.

That the loss of mechanical energy in a system always resulted in an increase of the system's temperature has been known for a long time, but it was the amateur physicist James Prescott Joule who first experimentally demonstrated how a certain amount of work done against friction resulted in a definite quantity of heat which should be conceived as the random motions of the particles that matter is composed of.

James Prescott Joule had been inspired to his investigations into the mechanical equivalent of heat by comparing the mass of coal consumed in a steam engine with the mass of zinc consumed in a Grove battery in performing a common quantity of mechanical work.