Friedrich Ernst Dorn

Infobox_Scientist
name = Friedrich Ernst Dorn


image_width =
caption = Friedrich Ernst Dorn
birth_date = birth date|1848|7|27
birth_place = Guttstadt (Dobre Miasto), Province of Prussia
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nationality = German
death_date = death date and age|1916|12|16|1848|7|27
death_place = Halle, Province of Saxony, Germany
field =Physics
work_institution = Halle University
alma_mater = University of Königsberg
doctoral_advisor =
doctoral_students =
known_for =
prizes =
religion =
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Friedrich Ernst Dorn (27 July 1848 – 16 December 1916) was a German physicist who was the first to discover that a radioactive substance, later named radon, is emitted from radium.

Life and work

Dorn was born in Guttstadt (Dobre Miasto), Province of Prussia, and died in Halle, Province of Saxony. He was educated at Königsberg and went on to teach at the university level. In 1885, at Halle University, Dorn took over the position of personal "ordinarius" professor for theoretical physics from Anton Oberbeck. Since Dorn was already an "ordinarius" professor [ The position of "ordinarius" professor outranks that of "extraordinarius" professor, which is comparable to that of associate professor.] , he was allowed to assume the title so as to not appear as having been demoted. [ Jungnickel and McCormmach, 1990b: p. 37] In 1895, Dorn succeeded Hermann Knoblauch at Halle as the "ordinarius" professor for experimental physics [In Germany, until the early twentieth century, experimental physics had priority over theoretical physics, and therefore such positions were considered to be higher in rank. This changed with the rise of German theoretical physics in the early twentieth century, especially through the activities of Max Born at the University of Göttingen and Arnold Sommerfeld at the University of Munich, who adroitly used experimental physics to test and develop their theories.] and director of the physics institute. Dorn’s previous duties were assumed by Karl Schmidt, who had been a Privatdozent and was called as an "extraordinarius" professor for theoretical physics. [ Jungnickel and McCormmach, 1990b: p. 293]

In 1900, Dorn published a paper in which he described experiments that repeated and extended some earlier work on thorium by Ernest Rutherford. Dorn verified Rutherford's observation that a radioactive material was emitted by thorium, and discovered that a similar emission arose from the element radium. [Cite journal | title = Die von radioactiven Substanzen ausgesandte Emanation | author = Dorn, F. E. | journal = Abhandlungen der Naturforschenden Gesellschaft (Halle) | year = 1900 | volume = 23 |pages = 1 – 15] Additional work by Rutherford and Soddy showed that the same emission came from both thorium and radium, that it was a gas, and that it was actually a new element. [cite book | author = Rutherford, E. | title = Radioactive Transformations | year = 1906 | publisher = Yale University Press | location = New Haven | pages = 70 – 94 ]

Dorn called the radioactive gaseous product from radium simply "emanation", but in 1904 Rutherford introduced the name "radium emanation" for the same material. Ramsay later suggested "niton", from the Latin word "nitens" meaning "shining". [cite book | author = Ramsay, W. | title = The Gases of the Atmosphere | year = 1915 | publisher = Macmillan | location = London | edition = 4 | pages = 283 ] In 1923 the name was again changed, this time to radon by an international body of scientists.

Marshall and Marshall have examined the original papers leading to radon's discovery and their work should be consulted for a full treatment and extensive references. [cite journal | author = Marshall, James L. | coauthors = Virginia R. Marshall | title = Ernest Rutherford, The "True Discoverer" of Radon | journal = Bulletin for the History of Chemistry | year = 2003 | volume = 28 | number = 2 | pages = 76 – 83 | url = http://www.scs.uiuc.edu/~mainzv/HIST/awards/OPA%20Papers/2003-Marshall.pdf ] They conclude that it is actually Rutherford who should be awarded credit for radon's discovery since he was the first to detect the element being emitted from any radioisotope (thorium) and the first to demonstrate radon's gaseous nature. Rutherford also was the first to integrate his own work on radon with that of others on radon's atomic mass, its spectrum, and its position on the periodic table.

References

Further reading

*Jungnickel, Christa and Russell McCormmach. "Intellectual Mastery of Nature. Theoretical Physics from Ohm to Einstein, Volume 1: The Torch of Mathematics, 1800 to 1870. " University of Chicago Press, 1990a.
*Jungnickel, Christa and Russell McCormmach. "Intellectual Mastery of Nature. Theoretical Physics from Ohm to Einstein, Volume 2: The Now Mighty Theoretical Physics, 1870 to 1925." University of Chicago Press, 1990b.
*Cite journal | author = Marshall, James L. | coauthors = Virginia R. Marshall | title = Ernest Rutherford, The "True Discoverer" of Radon | journal = Bulletin for the History of Chemistry | year = 2003 | volume = 28 | number = 2 | pages = 76 – 83 | url = http://www.scs.uiuc.edu/~mainzv/HIST/awards/OPA%20Papers/2003-Marshall.pdf
*Cite journal | title = The Discovery of the Elements. XIX. The Radioactive Elements | author = Weeks, Mary Elvira | journal = Journal of Chemical Education | year = 1933 | volume = |pages = 79 – 90
*Cite journal | title = Ernst Dorn | author = Wigand, A. | journal = Phys. Zeitschrift | year = 1916 | volume = 17 |pages = 299