James Prescott Joule (dec 24, 1818 – oct 11, 1889)

Description:

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.

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.

https://www.aps.org/publications/apsnews/201506/physicshistory.cfm

Added to timeline:

Date: