Johann Gottlob Leidenfrost (27 November 1715 – 2 December 1794) was a German

doctor Doctor or The Doctor may refer to: Personal titles * Doctor (title), the holder of an accredited academic degree * A medical practitioner, including: ** Physician ** Surgeon ** Dentist ** Veterinary physician ** Optometrist *Other roles ** ...

and

theologian Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...

who first described the scientific phenomenon

eponym An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''. Usage of the word The term ''epon ...

ously named the

Leidenfrost effect The Leidenfrost effect is a physical phenomenon in which a liquid, close to a surface that is significantly hotter than the liquid's boiling point, produces an insulating vapor layer that keeps the liquid from boiling rapidly. Because of this re ...

Personal life and career

Johann Gottlob Leidenfrost was born in Rosperwenda in the County of Stolberg-Stolberg. His father, Johann Heinrich Leidenfrost, was a well-known minister. Little is known of Leidenfrost's life prior to the start of his academic career. Leidenfrost first attended the

University of Gießen University of Giessen, official name Justus Liebig University Giessen (german: Justus-Liebig-Universität Gießen), is a large public research university in Giessen, Hesse, Germany. It is named after its most famous faculty member, Justus von L ...

where he followed in his father's footsteps by studying

theology Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...

. He soon switched his academic concentration to

medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...

, following that career path in his subsequent attendance at the

University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 Decemb ...

and the

University of Halle Martin Luther University of Halle-Wittenberg (german: Martin-Luther-Universität Halle-Wittenberg), also referred to as MLU, is a public, research-oriented university in the cities of Halle and Wittenberg and the largest and oldest university in ...

. 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 The First Silesian War (german: Erster Schlesischer Krieg, links=no) was a war between Prussia and Austria that lasted from 1740 to 1742 and resulted in Prussia's seizing most of the region of Silesia (now in south-western Poland) from Austria. T ...

. In 1743 Leidenfrost was offered and accepted a professorship at the

University of Duisburg The old University of Duisburg was a university in Duisburg, Germany. History Its origins date back to the 1555 decision to create a university for the unified duchies at the Lower Rhine that were later to be merged into Prussia. After the foundati ...

. In 1745 he married a local

Duisburg Duisburg () is a city in the Ruhr metropolitan area of the western German state of North Rhine-Westphalia. Lying on the confluence of the Rhine and the Ruhr rivers in the center of the Rhine-Ruhr Region, Duisburg is the 5th largest city in No ...

woman, Anna Cornelia Kalckhoff. Johann and Anna 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

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

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 Communis 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 Herman Boerhaave (, 31 December 1668 – 23 September 1738Underwood, E. Ashworth. "Boerhaave After Three Hundred Years." ''The British Medical Journal'' 4, no. 5634 (1968): 820–25. https://www.jstor.org/stable/20395297.) was a Dutch botanist, ...

in 1732). Leidenfrost died in Duisburg.

Leidenfrost effect

The effect Leidenfrost described is a

phenomenon A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried ...

in which a liquid, in near contact with a mass significantly hotter than its boiling point, produces an insulating

vapor In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Her ...

layer which keeps that liquid from boiling rapidly. It is most commonly seen when cooking; one sprinkles drops of water in a skillet to gauge its temperature. If the skillet's

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer. Thermometers are calibrated in various Conversion of units of temperature, temp ...

is at or above the ''Leidenfrost point'', the water skitters across the

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

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 more risky demonstrations, such as dipping a ''wet'' finger in molten lead or blowing out a mouthful of liquid nitrogen, both enacted without injury to the demonstrator. The Leidenfrost effect can be suppressed by virtue of structural design to decouple the liquid and vapor pathways, thus achieving the preferred superwetting and nucleate boiling of the liquid even on extremely high-temperature surfaces. As demonstrated in a structured thermal armor, the Leidenfrost effect can be prevented even over 1150 °C while maintaining efficient thermal cooling.

References

*everything2.com (2006)
"Leidenfrost effect"
Retrieved March 10, 2006. *Volcaniclightning.tripod.com/leidenfr.htm (2006

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. *Mengnan Jiang, et al. Nature, 2022.

External links

Leidenfrost – Ahnen (genealogy)

Scientists make water run uphill
*Carolyn Embach, ResearchGate: English translation of Johann Gottlob Leidenfrost, De aquae communes nonnullis qualitatibus tractatus, Duisburg on Rhine, 1756. (Carolyn S. E. Wares aka Carolyn Embach, translator, 1964) {{DEFAULTSORT:Leidenfrost, Johann Gottlob 1715 births 1794 deaths 18th-century German physicians 18th-century German Christian theologians People from Duisburg German male non-fiction writers 18th-century German writers 18th-century German male writers