Walther Hermann Nernst was a German physical chemist. In 1920, he received the Nobel Prize in chemistry for his work in thermochemistry and for his formulation of the third law of thermodynamics (1906), also known as the Nernst Heat Theorem. The third law states that if all the thermal motion of molecules (kinetic energy) could be removed, a state called absolute zero would occur. Absolute zero results in a temperature of 0° Kelvin or -273.15° Celsius. This is the work for which he is best remembered, as it provided a means of determining free energies (and therefore equilibrium points) of chemical reactions from heat measurements. Theodore Richards claimed Nernst had stolen the idea from him, but Nernst is almost universally credited with the discovery.

Nernst applied the principles of thermodynamics to the electric cell. He constructed the Nernst Equation, which related the voltage of a cell to the cell's properties. He also was first to explain the ionization of certain substances when dissolved in water and  invented an electric metallic-filament lamp, a link between the carbon lamp and the incandescent lamp, in 1898.

Nernst also was an early pioneer of Germany's chemical weapons research program during World War I.

Sources

• Cleveland, Cutler (Lead Author); Peter Saundry (Topic Editor). 2008. "Nernst, Walther Hermann." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth March 19, 2007; Last revised August 22, 2008; Retrieved August 12, 2009]. 
• Wikipedia Contributors, Walther Nernst, Wikipedia The Free Encyclopedia, Accessed 12 August 2009.