Joule  (jōōl, joul)  British physicist who established the mechanical theory of heat and discovered the first law of thermodynamics. |
| Joule, James Prescott 1818-1889.
British physicist who demonstrated that heat is a form of energy. His work established the law of conservation of energy, stating that energy is never destroyed but may be converted from one form into another. The joule unit of energy is named for him. |