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

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.

Personal life and career

Johann Gottlob Leidenfrost was born in

Rosperwenda Berga is a municipality in the Mansfeld-Südharz district, Saxony-Anhalt, Germany. The municipality consists of three villages: * Berga * Bösenrode * Rosperwenda Berga-Kelbra station, which is on the Halle–Hann. Münden railway } The Ha ...

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 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 th ...

. He soon switched his academic concentration to

medicine Medicine is the science and Praxis (process), practice of caring for a patient, managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, and Health promotion ...

, 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 i ...

. 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 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 founda ...

. 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 Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χρισ ...

. 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 rel ...

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 in 1732). Leidenfrost died in Duisburg.

Leidenfrost effect

The effect Leidenfrost described is a

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

in which a

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, an ...

, 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. H ...

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 measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on ...

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 typi ...

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 Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is wi ...

, 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 Johann Gottlob Leidenfrost (27 November 1715 – 2 December 1794) was a German doctor and theologian who first described the scientific phenomenon eponymously named the Leidenfrost effect. Personal life and career Johann Gottlob Leidenfrost was ...

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