Walther Hermann Nernst

Walther Hermann Nernst
(1864-1941)

German scientist who was one of the founders of modern physical chemistry. His formulation of the third law of thermodynamics gained him the 1920 Nobel Prize for Chemistry. Simply stated, the law postulates that, at a temperature above absolute zero, all matter tends toward random motion and all energy tends to dissipate.
Educated at the universities of Zurich, Graz (Austria), and Wurzburg, in 1887 Nernst became an assistant to Wilhelm Ostwald who, with Jacobus van't Hoff and Svante Arrhenius, was establishing the independence of physical chemistry. He was appointed to the physics department of the University of Gottingen in 1890 and in 1905 went to the University of Berlin, where he was director of the Institute for Experimental Physics from 1924 to 1933.

In 1906 Nernst announced his heat theorem, or third law of thermodynamics, in which he postulated that entropy has an absolute value such that crystalline materials have zero entropy at the temperature of absolute zero (273 C). In practical terms, this theorem implies the impossibility of attaining absolute zero, since as a system approaches absolute zero, the further extraction of energy from that system becomes more and more difficult. Modern science has attained temperatures only one-millionth of a degree above absolute zero, but absolute zero itself cannot be reached.

Nernst also conducted important research on the theory of galvanic cells, the thermodynamics of chemical equilibrium, the properties of vapours at high temperature and of solids at low temperature, and the mechanism of photochemistry. Nernst was also interested in applied science. He invented an improved electric light and an electronically amplified piano. His influential textbook of theoretical chemistry was first published in 1893. In later years he concerned himself chiefly with astrophysical theories.