3rd March 2021, 11:00am


James Prescott Joule - From brewing beer to the First Law of Thermodynamics

A student of John Dalton, James Joule is heralded as the father of thermodynamics. Joule’s initial theories were cast aside in 1843, and he was considered something of a madcap until 1872, when he was named the President of the British Association for the Advancement of Science.

The Salfordian’s breakthrough arose due to the confluence of Dalton’s tuition and Joule’s hobby of brewing beer. Joule’s experimentation culminated in the discovery that heat is a form of energy. Not bad for an amateur scientist.

Joule’s First Law defined the relationship between the amount of heat generated and the current that is passed through a conductor. Following this he began to take his experiments further.  Joule’s next discovery—that heat could be generated by a current—went against the accepted theory of the time, the caloric theory. Joule’s theories were considered too much of a reach for his peers, and when he presented his results to a meeting of the British Association for the Advancement of Science in 1843, Joule’s presentation was met by a stone cold silence.

In 1847, Joule presented his ideas once again to the British Association for the Advancement of Science. At the seminar, both Lord Kelvin and Michael Faraday—Joule’s rivals—were in attendance for what would be a formative event within physics. During the presentation, Joule illustrated what would become the First Law of Thermodynamics, cementing his legacy as a scientific visionary by silencing his early critics.

Today, there stands a statue of James Prescott Joule in the Manchester Town Hall, created by Sir Alfred Gilbert in 1893. The statue is in the entrance to the Town Hall, opposite Francis Chantrey’s sculpture of Joule’s mentor John Dalton.  His former home, where he lived and worked, can be found at The Crescent in Salford.


James Joule is revered as one of the greatest scientists in the history of physics. As someone who was a Salford resident, a student of fellow famous Manchester scientist, John Dalton, and spent the majority of his working life in and around Greater Manchester, his story is one the Science and Industry Museum is proud to tell, and we’re delighted that he is being celebrated as a pioneer by the Manchester Lit and Phil.

Joule's experiments led him to a new understanding of energy conversion in 1845, and this research led to the development of the first law of thermodynamics which is fundamental to our understanding of the world. He is remembered as one of the founders of modern physics, and from 1948 the ‘Joule’ became a standard international unit of energy measurement. It is fantastic that his work is being highlighted by the Manchester Lit and Phil, who I’m sure are very proud to name him as a former president.

Sarah Baines, Curator of Engineering at the Science and Industry Museum


Discover more

  • 'James Joule: From Establishment Irritant to Honoured Scientist' - article on the Science and Industry Museum's website
  • A number of Joule’s apparatus are now part of the Science Museum Group’s collection. This travelling microscope was used by Joule for experiments about energy. He had to make incredibly precise, tiny measurements to prove his new theories about how heat works and this microscope made by Abraham & Dancer in 1843 helped him do that.  You can see some of Joule’s apparatus on display at the Science and Industry Museum when their doors reopen later this year.