Johann Andreas von Segner

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Johann Andreas von Segner

Johann Andreas von Segner , also Ján Andrej Segner or János András Segner , (born October 9, 1704 in Preßburg , † October 5, 1777 in Halle ) was a mathematician , physicist and doctor . A water wheel named after him is considered the forerunner of the Pelton turbine .

Life

Göttingen memorial plaque for Johann Andreas von Segner

Johann Andreas von Segner was born as the son of the Pressburg city ​​treasurer and tax collector Johann Michael von Segner. From 1714 he attended the city high school , and early on he showed special talents in mathematics and physics . In 1725 he began studying medicine , philosophy and mathematics at the University of Jena . Even before his graduation, he published various smaller articles. As a doctor of medicine he worked again in his hometown from 1730. However, this work did not prove to be satisfactory for him, and so he returned to Jena two years later (1732) , earned his master's degree at the university and lectured in mathematics and medicine as a private lecturer from 1733. In 1735 he accepted a call to Göttingen for the professorship for mathematics and natural science ( natural science ) created especially for him. As one of the first natural scientists , he held experimental lectures in chemistry , and he was also responsible for building the university observatory in Göttingen . In 1754 he was appointed professor of mathematics and physics to succeed the philosopher and mathematician Christian Wolff at the University of Halle . Here, too, he had the Halle observatory built. Christian Garve (1766) and August Niemeyer (1777) were among his students who did their doctorate with him in Halle .

As one of the most important natural scientists of his time, Segner was a member of the Prussian Academy of Sciences in Berlin (1746), the Royal Society London (1738) and the Russian Academy of Sciences Saint Petersburg (1753). From 1751 to 1753 he was a full member of the Göttingen Academy of Sciences .

His grave is in the town of Halle .

plant

Segner's water wheel

During his time in Göttingen, Segner published two scientific papers in 1750 that dealt with problems of hydrodynamics .

In it he presented the principle of a water wheel, which, as Segner's water wheel, became the forerunner of turbine technology. The wheel uses the potential energy as a reaction water wheel . The water pressure generates a circular movement with appropriately arranged nozzles. Some lawn sprinklers use this principle , which rotate through the recoil of the tangentially exiting water. This principle was first used in antiquity with the aeolipile , which Heron of Alexandria operated with steam. The blade tip drive used in some helicopters is also closely related. Segner's construction was picked up by Leonhard Euler and others and given suggestions for improvement. The figure shows the basic structure in longitudinal section (A, B: water inlet; B: axis of rotation; C: nozzles; F, G: decoupling of the rotary movement) and cross-section (D: tangentially curved nozzles).

Segner conducted further studies on the symmetry axes of solid bodies, on air pressure , on the surface tension of liquids (especially on capillarity ) and on solar eclipses . In Halle he worked on the weekly Halle advertisements outside the university .

In psychology, Segner is often associated with the first study of iconic memory ; In 1740 he is said to have carried out an experiment in which he let glowing coal rotate on a wheel; In a dark room, the observer found a steady image at approx. 100 ms; then called visual persistence.

Appreciations

A street and a school in Halle are named after Segner, in 1956 Segnerstrasse in Vienna was named after him.

The Segner crater on the moon bears his name. The asteroid (28878) Segner is also named after him.

Fonts

  • Specimen logicae universaliter demonstratae. (Ienae1740) Reprint published with English introduction by Mirella Capozzi, Bologna: CLUEB, 1990.
  • In contemplationibus hydraulicis pergit. (Gottingae 1746)
  • Clear and complete lectures on arithmetic and geometry: for the use of those who want to practice these sciences through their own diligence. (Lemgo 1747)
  • Introduction to nature. (Göttingen 1750)
  • Superficies fluidorum concavas ostendit. (Gottingae 1750)
  • Programma Qvo Principivm Parsimoniae Vniversaliter Demonstratvr Atqve Dissertatio Inavgvralis Medica Indicitvr. (Gottingae 1754)
  • Cursus mathematici. (5 volumes, hall 1758–1768)
  • The beginnings of arithmetic, geometry and geometrical calculations, from d. Lat. trans. (Hall 1773)

literature

Web links

Commons : Johann Andreas von Segner  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 223.


personal data
SURNAME Segner, Johann Andreas von
ALTERNATIVE NAMES Segner, Jan Andrej; Segner, János András
BRIEF DESCRIPTION German physicist and mathematician
DATE OF BIRTH October 9, 1704
PLACE OF BIRTH Pressburg
DATE OF DEATH October 5, 1777
Place of death Halle (Saale)