Hermann von Helmholtz

Life

Hermann Ludwig Ferdinand von Helmholtz was a German physician and physicist who was born August 31, 1821 and died September 8, 1894. He was the eldest of four siblings and had many health problems so he was confined to his home for the first seven years of his life. His father was a philosophy and literature teacher and his mother was a descendent of William Penn, the founder of Pennsylvania. His father introduced him to the philosophy of Fitche and Kant and introduced him "to approach to nature that flowed from their philosophical insights." Many thought that scientific conclusions about nature could be deduced from philosophical ideas and much of Helmholtz's work was devoted to refuting this idea.

His work is influenced by the philosophers of Fichte and Kant. His father wanted him to study medicine, but he wanted to study natural science, so he ended up going to the Charité because financial support was provided to the medical students on the condition that he serves for eight years as an army doctor. When he went to his army assignment his duties were few so he set up a makeshift laboratory in the barracks to do experiments.

HE married Olga von Velten. He was released from his military duties early because of his scientific talents and in 1848 he was appointed assistant at the Anatomical Museum and lecturer at the Academy of Fine Arts in Berlin, and the next year he moved to become an assistant professor and director at the Physiological Institute, and in 1855 he became a professor of anatomy and physiology. In 1871 he became a professor of physics at the University of Berlin, and in 1888 he was appointed as the first director of the Physico-Technical Institute and that was his final job.

His Work and Discoveries

Most of Helmholtz's work is rooted in his rejection of Nature Philosophy. "Nature philosophy derived from Kant, who in the 1780s had suggested that the concepts of time, space and causation were not products of sense experience but mental attributes by which is was possible to perceive the world...Futhermore, all science could and should be reduced to the laws of classical mechanics, which, in his view, encompassed matter, force, and, later, energy, as the whole of reality"

He began his doctoral thesis in 1842 on the connection between nerve fibres and nerve cells, which led him to later study animal heat. He supposed that if vital heat "were not the sum of all the heats of the substances involved in chemical reactions within the organic body, there must be some other source of heat not subject to physical laws...Hence, Helmholtz concluded, vital heat must be the product of mechanical forces within the organism. From there he went on to generalize his results to state that all heat was related to ordinary forces and, finally, to state that force itself could never be destroyed. He detailed all his findings in his paper "On the Conservation of Force." For physical sciences it was one of the first statements on the principle of the CONSERVATION OF ENERGY. He also wrote a book called the "Handbook of Physiological Optics."

He spent some of his last years unsuccessfully trying to reduce electrodynamics to a minimum set of mathematical principles. Even though he couldn't formulate electrodynamics, he was successful in deducing almost all electromagnetic effects from the ether's supposed properties. Later on though the special and general theories of relativity that Helmholtz had proposed were destroyed by Einstein by eliminating the ether. Helmholtz also worked on wave motion and in his later years he studied meteorology.

Equations

The Helmholtz energy is defined as:

A = U - TS

    A=Helmholtz free energy
    U=internal energy of the system
    T=absolute temperature
    S=entropy of the system

Sources

http://www.britannica.com/biography/Hermann-von-Helmholtz https://en.wikipedia.org/wiki/Hermann_von_Helmholtz