Johann Gottlob Leidenfrost
Johann Gottlob Leidenfrost (
November 27,
1715 -
December 2,
1794) was a
German doctor and
theologian who first described the scientific phenomenon
eponymously named the
Leidenfrost effect.
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Johann Gottlob Leidenfrost |
Johann Gottlob Leidenfrost was born on November 27, 1715 in the town of Ortenberg in the County of
Stollberg,
Germany. His father, Johann Heinrich Leidenfrost, was a well-known minister. Little is know of Leidenfrost's life prior to the start of his academic career.
Leidenfrost first attended
Justus Liebig University where he followed in his father's footsteps by studying
theology. He soon switched his academic concentration to
medicine, following that career path in his subsequent attendance at the
University of Leipzig and the University of Halle in
Westphalia.
In
1741 he was awarded a doctorate in medicine largely based on a well-received treatise on the study of the movement of the human body, entitled
On the Harmonious Relationship of Movements in the Human Body. After the conclusion of his academic studies, Leidenfrost spent some years traveling and took a post as a field physician in the
first Silesian War.
In
1743 Leidenfrost was offered and accepted a professorship at
University of Duisburg. In
1745 he married a local
Duisburg woman, Anna Cornelia Kalckhoff. Johann and Ann had seven children together, including Johanna Ulricke (
1752-
1819), who was later the wife of the noted German theologian, Christian Krafft. In addition to teaching
medicine,
physics and
chemistry at the University of Duisburg, Leidenfrost also functioned as the university's rector, all the while maintaining a private medical practice.
In
1756, Leidenfrost became a member of the
Berlin Academy of Sciences. During his lifetime, Leidenfrost published more than seventy manuscripts, including
De Aquae COMM universities Nonnullis Qualitatibus Tractatus (1756) ("A Tract About Some Qualities of Common Water") in which the
Leidenfrost effect was first described (although the phenomenon had been previously observed by
Herman Boerhaave in
1732). Leidenfrost died on December 2, 1794 in Duisburg, exactly two hundred years to the day after
Gerardus Mercator.
The effect Leidenfrost described is a
phenomenon in which a liquid, in near contact with a mass significantly hotter than its
boiling point, produces an insulating
vapor layer which keeps that liquid from
boiling rapidly. This is most commonly seen when cooking; one sprinkles drops of water in a skillet to gauge its temperatureâ€"if the skillet's
temperature is at or above the
Leidenfrost point, the water skitters across the
metal and takes
longer to evaporate than it would in a skillet that is hot, but at a temperature below the
Leidenfrost point. It has also been used in some dangerous demonstrations, such as dipping a
wet finger in molten lead and blowing out a mouthful of
liquid nitrogen, both enacted without injury to the demonstrator.
*everything2.com (2006).
"Leidenfrost effect". Retrieved March 10, 2006.
*Volcaniclightning.tripod.com/leidenfr.htm (2006)
"Leidenfrost`s Phenomenon J.G.Leidenfrost". Retrieved March 10, 2006.
*
Johann Gottlob Leidenfrost from the German-language Wikipedia. Retrieved March 10, 2006 and containing the internal references:
*Born, Gernot and Kopatschek, Frank,
Die alte Universität Duisburg 1655 - 1818; Duisburg 1992.
*Ring, Walter
Geschichte der Universität Duisburg. Mit einem Lageplan; Duisburg 1920.
*von Roden, Günter,
Geschichte der Stadt Duisburg; 2 Bde., 2. verbess. Aufl., Duisburg 1979.
*
Leidenfrost - Ahnen (genealogy).
*
Scientists make water run uphill
