James Prescott Joule, born in Manchester, England, lived from 1818-1889. His father was a prosperous brewery owner. James was born during the Romanticism Age and the Industrial Revolution. He was home schooled, and then at sixteen, was sent to Cambridge. There he studied with John Dalton, a British Chemist. After graduating, he began to study on his own, in a laboratory, at his father's house.
Most of his research had to do with the production of heat. At first he wanted to improve electric motor efficiency, to replace steam engines. He discovered that the heat generated by an electrical current was proportional to the square of the current. James presented this in paper to the Royal Society. After this he made many reports about heat and other energy forms. Joule is recognized for the cooling effect that occurs when a gas is rapidly expanded, used in refrigeration. Also, in 1850, he discovered the equivalence between mechanical work and amounts of heat in his well known "paddle-wheel experiment".
Not only was James Joule a researcher, but an inventor. Many things he discovered go into new technologies and devices today. Today, he is recognized for electrical welding and the displacement pump.
Towards the end of his life, around 1875, he ran out of money doing his experiments, because he paid for most of them. Shortly after that, he became ill and died. In his honor, a unit of energy, the Joule, was named after him.