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Hermann Walther Nernst (1864-1941)
German physicist and chemist

As a young man in Prussia, Hermann Walther Nernst (1864-1941) expressed his ambition to become a poet. In 1883, he had graduated first in his class at the Gymnasium of Graudenz, where his studies focused on classical literature, humanities, and natural science. Thirty-seven years later, he was awarded the Nobel Prize for chemistry in honor of his work in chemical thermodynamics. The man who adored the words of Shakespeare created poetry of a different meter when he bridged the quantum theory of Planck with the dynamics of chemical processes.
 
 

Walther Hermann Nernst was born in Briesen, West Prussia (now Wabrzezno near Torun, Poland), on June 25, 1864. His father, Gustav Nernst, was a district judge. He spent his early school years (Gymnasium) at Graudentz (now Grudziadz, Poland), and subsequently went to the Universities of Zurich, Berlin and Graz (Ludwig Boltzmann and Albert von Ettinghausen), studying physics and mathematics. At Graz, he worked with von Ettinghausen, with whom he published work in 1886 which formed part of the experimental foundation of the modern electronic theory of metals. He took his Ph.D. at Würzburg (Friedrich Kohlrausch), beginning his career as a physicist. He graduated in 1887 with a thesis on electromotive forces produced by magnetism in heated metal plates. Nernst's first outstanding work was his theory of the electromotive force of the voltaic cell (1888). He developed methods for measuring dielectric constants and was the first to show that solvents of high dielectric constants promote the ionization of substances. Nernst proposed the theory of solubility product, generalized the distribution law, and offered a theory of heterogeneous reactions.


 

He joined Wilhelm Ostwald at Leipzig University, where van't Hoff and Arrhenius were already established, and it was in this distinguished company of physical chemists that Nernst began his important researches. Nernst's early studies in electrochemistry were inspired by Arrhenius' dissociation theory which first recognized the importance of ions in solution. In 1889 he elucidated the theory of galvanic cells by assuming an "electrolytic pressure of dissolution" which forces ions from electrodes into solution and which was opposed to the osmotic pressure of the dissolved ions. In the same year he derived equations which defined the conditions by which solids precipitate from saturated solutions. Nernst applied the principles of thermodynamics to the chemical reactions proceeding in a battery. In 1889, he showed how the characteristics of the current produced could be used to calculate the free energy change in the chemical reaction producing the current. Nernst first explained the ionization of certain substances when dissolved in water. He constructed an equation, known as the Nernst Equation, which related the voltage of a cell to its properties. This equation has also very important biophysical implementations. Independently of Thomson, he explained why compounds ionize easily in water. The explanation, called the Nernst-Thomson rule, holds that it is difficult for charged ions to attract each other through insulating water molecules, so they dissociate.


 

In 1894 he received invitations to the Physics Chairs in Munich and in Berlin, as well as to the Physical Chemistry Chair in Göttingen. He accepted this latter invitation, and in Göttingen founded the Institute for Physical Chemistry and Electrochemistry and became its Director. His transition to chemistry actually began in Leipzig, but developed fully in his subsequent position as an associate professor of physics at Göttingen.


 

Walther Nernst in his
laboratory, 1921

In 1905, he was appointed Professor of physical chemistry in the University of Berlin. His heat theorem, known as the Third Law of Thermodynamics, was developed in 1906. It demonstrated that the maximum work obtainable from a process could be calculated from the heat evolved at temperatures close to absolute zero - earlier ideas had not considered the effects of temperature - and conditions of equilibrium in many chemical reactions could now be precisely worked out. The law predicts that absolute zero cannot be attained, 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. Simply stated, the law postulates that, at a temperature above absolute zero, all matter tends toward random motion and all energy tends to dissipate. In addition to its theoretical implications, the theorem was soon applied to industrial problems, induding calculations in ammonia synthesis.


 

Nernst and his students in Berlin proceeded to make many important physico-chemical measurements, particularly determinations of specific heats of solids at very low temperatures and of vapour densities at high temperatures. All these were considered from the point of view of quantum theory. In 1914 Walther Hermann Nernst and Max Planck succeeded in bringing Albert Einstein to Berlin.

In 1918 his studies of photochemistry led him to his atom chain reaction theory. This assumed that once the energy of a quantum has initiated a reaction in which free atoms are formed, these formed atoms can themselves decompose other molecules with the liberation of more free atoms and so on. The reaction can thus continue for long periods without further outside initiations. He explained the H2-Cl2 explosion on exposure to light as an atom chain reaction.
 

William Henry Bragg, Marcel Louis Brillouin, Louis de Broglie, Marie Curie, Albert Einstein, James Hopwood Jeans, Heike Kamerlingh Onnes, Martin Hans Christian Knudsen, Paul Langevin, Max von Laue, Hendrik Antoon Lorentz, Walther Nernst, Heinrich Rubens, Ernest Rutherford, Arnold Johannes Wilhelm Sommerfeld, Joseph John Thomson, Emil Gabriel Warburg, Wilhelm Wien, Robert Williams Wood (October 1913, Second Solvay Congress; Brussels)


 

Nernst was mechanically minded and he was always to the forefront in considering ways of applying the results of scientific research to industry. His improved electric light, the Nernst Lamp, used a ceramic body and it might have assumed importance had not tantalum and tungsten filaments been developed. His electrical piano, which replaced the sounding board with radio amplifiers, did not gain acceptance among musicians. In later years, he occupied himself with astrophysical theories, a field in which the heat theorem had important applications.


For his work in thermochemistry he received the Nobel Prize in Chemistry for 1920, but his research encompassed a far broader scope, including photochemistry, electrochemistry, electroacoustics, astrophysics and studies of high temperature gases. Many other distinctions and awards were bestowed upon him for his contributions to science.


 
A stamp deducated to Nernst's Nobel prize
Day of issue: November 18, 1980 Value: 2 kr
Design: Lennart Forsberg
Engraver: Arne Wallhorn Printing process:
Recess Printed at: The Post Office Stamp
Printing Works.

Walther Nernst's fundamental contributions to electrochemistry, the theory of solutions, thermodynamics, solid state chemistry and photochemistry are recorded in a series of monographs, and in his many papers to learned societies, etc. His book "Theoretische Chemie vom Standpunkte der Avogadro'schen Regel und der Thermodynamik" ("Theoretical chemistry from the standpoint of Avogadro's rule and thermodynamics") was first published in 1893 and the tenth edition appeared in 1921 (the fifth English edition in 1923). Together with A. Schonflies he wrote a textbook "Einführung in die mathematische Behandlung der Naturwissenschaften" ("Introduction to the mathematical study of the natural sciences"), which reached its tenth edition in 1923. Of his other books, his monograph "Die theoretischen und experimentellen Grundlagen des neuen Wärmesatzes" (1918, second edition 1923) was also published in English ("The New Heat Theorem", 1926).
 


ca. 1938

He became director of the "Physikalisch-Technisches Reichsanstalt" in 1922 and finally professor of physics at Berlin in 1924 before retiring in 1933.

left to right: Nernst, Einstein, Planck, Millikan, Laue; on the occasion of Millikan's visit to Berlin, 1928


 

Nernst married Emma Lohmeyer in 1892. They had two sons, who were both killed in the First World War, and three daughters. His favourite pastimes were hunting and fishing.


 
Chain Reactions

There are actually many kinds of chain reaction, using intermediaries other than heat. The best known is the nuclear chain reaction, in which neutrons cause atoms of uranium or plutonium to split (fission"), releasing more neutrons, and so on. Walther Nernst of course did not know about nuclei, but he did grasp the principle of chain reactions and the possibility that they could be intermediated by other than heat. In particular, it was known that a gaseous mixture of hydrogen and chlorine explodes when exposed to light, but the process was not understood. He proposed and provided evidence that the reaction, once stared, proceeds purely chemically. Hydrogen and chlorine gases are normally made up of 2-atom molecules. These molecules are quite stable and non-reactive. Light can "dissociate" the chlorine molecules into two atoms, and the separated atoms are highly reactive. Each wanders around until it meets a hydrogen molecule, at which point it proceeds to "steal" one of the hydrogen atoms from its companion to make a stable hydrogen chloride molecule. The remaining hydrogen atom is also highly reactive and "steals" a chlorine atom from its companion... and so on. Since the reactions are rapid and "exothermic", or heat-releasing, an explosion occurs. 


The "internal combustion" (petrol or diesel) engine which drives almost all our cars, and trucks was invented before the turn of the century. In this engine, gaseous mixtures of petroleum and oxygen explode, heating the gases, whose expansion then drives pistons. These engines have an "efficiency", meaning the fraction of heat energy which is converted into mechanical movement, of some 20-30%. But until Nernst, it was not possible to calculate the theoretical maximum efficiency of such an engine from knowledge of atomic affinities. Nernst developed this theory, which is so important that it is called "The Third Law of Thermodynamics "and which had, and still has, great scientific and industrial importance.


 
Nervous Signals

Of Nernst's many contributions to physical chemistry - the understanding of chemical principles in terms of underlying physical laws - one in particular is enshrined in the name "The Nernst Equation". This equation is particularly important in the understanding of how our nerves work. The language of the nervous system is electrical. The cells of our brains "talk" to one another electrically, our senses use electrical impulses to pass information to the brain, and the brain's orders to the muscles are coded in such impulses. The "wires" carrying these impulses, the nerve fibres, are not metal (evolution seems never to have discovered how to make metal wires) but are instead fine fatty tubes filled with a water solution of electrically charged atoms called "ions". It is the flow of these ions through pores in the membranes which form the walls of the tubes that sustains the passage of the electrical impulses, rather than the flow of electrons along wires as in technological communication devices such as telephones. Nernst's Equation describes the balance between the two factors determining the flow of the ions across the membrane: The tendency of the ions to flow from the side of the membrane with the higher concentration to that with the lower concentration; and the force on the ions arising from any difference in the electrical potential between the two sides of the membrane. This equation is so central to the understanding of nerve action that neurobiologist Gordon Shepherd says in his book: "If you learn only one equation in your study of neurobiology, the Nernst equation is the one to learn, because it is fundamental to the nature of electrical potentials in all cells as well as the electrical activity in neurons."


 
A National Hero

Nernst was showered with many honours during his life, including the 1920 Nobel Prize. In only one discipline he failed: As an inventor. None of his inventions bore fruit, though one, the electric piano, was simply before its time: He replaced the sounding board of a piano with radio amplifiers - but the result did not please the musicians... Having lost his two sons in The First World War, Nernst was something of a national hero. But his pacifist views were not welcomed by the Nazis, and when they came to power in 1933, he retired to his estate and took no further part in academic or civil life. He died in Muskau, Germany, on November 18, 1941.

See also related pages:
Hermann Walther Nernst, Nobel Prize in Chemistry 1920 - Prize Presentation

The Nernst equation


This text has been compiled from the biographies of Nernstl available in the Internet:
( 1, 2, 3, 4, 5, 6, 7)

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