Sunday, August 26, 2012
After briefly working in Frankfurt-am-Main Frank returned to Berlin to work as an assistant for Heinrich Ruben, where he studied the structure of the electron shells of atoms and molecules, using atomic collisions. In 1911 Franck became a lecturer at the University of Berlin and when World War I broke out he enlisted and served as a private. In the war he was wounded, awarded the Iron Cross, first class, and then was promoted to lieutenant, despite his Jewish heritage. After his promotion he was assigned to a chemical warfare unit led by Fritz Haber, where he became Haber's assistant. After the war, at Haber's suggestion, Franck took a job at the Kaiser Wilhelm Institute of Physical Chemistry and in 1918 he became the head of the physics department.
Franck worked with Gustav Hertz and they studied the nature of electron collisions with atoms. From this work they were able to demonstrate the quantized nature of energy from electron transitions in atoms. In 1900 Max Planck had hypothesized that the energy emitted by excited atoms (atoms with electrons above their ground or lowest energy states) come in discrete amounts. When excited electrons fall back to their ground states they emit energy in the form of electromagnetic radiation. Because there are distinct electronic orbitals around the nucleus when electrons transition between these their emissions only come at certain wavelengths that depend on which orbitals the electrons transition between. Franck and Hertz's experiments were the first experimental demonstration of the quantized nature of electronic transitions. For these experiments Franck and Hertz were awarded the 1925 Nobel Prize in Physics.
In 1920 Franck moved to Gottingen where he was a professor of experimental physics at the Physical Institute. Franck's laboratory in Gottingen became a center for study of atomic and molecular physics and many important physicists studied there. In 1933, when the Nazis came to power in Germany, Franck moved to Baltimore, Maryland, where he was the Speyer Professor of Physics at Johns Hopkins University. He then spent a year in Copenhagen, Denmark, where he was a guest professor. In 1935 he returned to Johns Hopkins as a physics professor. He stayed at Johns Hopkins until 1938, when he moved to the University of Chicago, becoming a professor of physical chemistry. During World War II Franck was the director of the Chemistry Division of the Metallurgical Laboratory, which was part of the Manhattan Project. In 1945 he served as the chairman of the committee that produced the Franck Report, a document signed by several prominent physicists urging the United States Government not to use the atomic bomb on Japan and predicting the arms race. He became a professor emeritus at the University of Chicago in 1947, but continued doing research with the Photosynthesis Research Group until 1956.
Other honors won by Franck include the Planck Medal from the German Physical Society in 1951, the Rumford Medal in 1955 from the American Academy of Arts and Sciences for his work on photosynthesis and election as a foreign member of the Royal Society of London in 1964.
Franck died suddenly while on a brief trip to Gottingen on May 21,1963, at the age of 81.
Rice, Stuart A. and Jortner, Joshua; "James Franck 1882-1964"; National Academy Press; 2010
James Franck Nobel Biography
James Franck Wikipedia Entry
Sunday, August 19, 2012
In 1675 Flamsteed visited London and with the help of Moore was able to get an audience with king Charles II. Flamsteed had won the favor of the king by building a barometer for him the previous year. Charles II appointed Flamsteed his Royal Astronomer. Greenwich Observatory was built for his observations and he began observing there in 1676. Flamsteed was a careful observer and his project was to observe and catalog the locations of the stars. Over the forty years of his project he cataloged the positions of 3000 stars. Flamsteed was a meticulous worker and did not want to publish any results until they all were checked. Isaac Newton became impatient for the results of the catalog and obtained a pirated copy of the work, which he and Edmund Hally published. Flamsteed was so angry at this that he obtained 300 of the 400 copies that were printed and burned them. Because of this Flamsteed came to view Newton and Halley as his enemies. The finished catalog was not published until 1725.
Other accomplishments credited to Flamesteed include accurate predictions of the solar eclipses of 1666 and 1668 and the invention of the conical projection which is used in cartography. Even before his visit to London and appointment to become the first astronomer royal, Flamsteed had been ordained and he served as a parish priest in Burstow, Surrey. Honors won by Flamsteed include election to the Royal Society in 1677 and a crater on the moon and an asteroid named after him.
Flamsteed died on December 31, 1719 and he was replaced as astronomer royal by his enemy Edmund Hally.
O'Conner, J.J. and Robertson, E.F.; "John Flamsteed"; found at www-history.mcs.st-and.ac.uk
Moulton, Charles Wells; Library of Literary Criticism of English and American Authors, Vol. 2, 1639-1729; Henry Malkan, Publisher; 1910
John Flamsteed Wikipedia Entry