Born: 27 November 1903, Kristiania (now Oslo), Norway
Died: 5 October 1976, Coral Gables, FL, USA
Affiliation at the time of the award: Yale University, New Haven, CT, USA
Prize motivation: "for the discovery of the reciprocal relations bearing his name, which are fundamental for the thermodynamics of irreversible processes"
Field: chemical thermodynamics, physical chemistry
Prize share: 1/1
Thermodynamics is about heat and its conversion into other forms of energy - basically involving statistical descriptions of atomic and molecular movements. Irreversible thermodynamic processes go in only one direction and not in the reverse. Lars Onsager analyzed mathematical equations for various irreversible thermodynamic processes and in 1931 found the connection that led him to formulate equations that came to be known as reciprocal relations. This allowed a complete description of irreversible processes.