Happy birthday anniversary to James prescott Joule..... James Prescott Joule experimented with engines, electricity and heat throughout his life. Joule’s findings resulted in his development of the mechanical theory of heat and Joule’s law, which quantitatively describes the rate at which heat energy is produced from electric energy by the resistance in a circuit. Initially many 19th century scientists were skeptical of Joule’s work, but his efforts proved fundamental to the modern understanding