Siméon Denis Poisson

Siméon Denis Poisson (* June 21, 1781 in Pithiviers ( Loiret ), † April 25, 1840 in Paris) was a French physicist and mathematician.

Career

He was born the son of a soldier and subsequent administrative officials Siméon Poisson Pithiviers. After his father's request Poisson should be a doctor. For this purpose he was sent to train to an uncle in Fontainebleau, who practiced there as a surgeon. However, he broke off the course. In 1796 Poisson was sent to the École centrale in Fontainebleau, one founded by the Executive Board, Le Directoire school. Him to study at the École Polytechnique in Paris, recommended by his good mathematical achievements.

There, at the École Polytechnique Poisson began to study mathematics in 1798, where he made ​​the acquaintance of Laplace and Lagrange. Already in 1800 he successfully finished his studies with a thesis on Bézouts Étienne ( 1730-1783 ) theorem and theory of equations. In 1802 he became a professor in 1806 and took over the chair of Jean Baptiste Joseph Fourier, after it had been sent by Napoleon to Grenoble. As of July 1807, he was mentioned in the Memoires de Physique et de Chimie de la Société d' Arcueil as a member of the Société d' Arcueil.

In 1817 he married Nancy de Bardi, a child born in England orphan emigre parents. He had four children with her. He is immortalized in particular on the Eiffel Tower, see: The 72 names on the Eiffel Tower.

The lunar crater Poisson is named after him.

Scientific Work

Poisson was a student of Pierre Simon Laplace and dealt with the physical principles of waves, worked on acoustics, elasticity and heat as well as the electrical properties of solid bodies. 1812 he publishes an extension of the Laplace equation for the surface charge. In 1818 he told the Poisson spot ahead when light should have wave character. This he doubted however. He led with Augustin Jean Fresnel heated discussions as an advocate of the wave theory of light. The dispute was ended by the experimental proof of the spot by François Arago. In 1838 he published his theory of probability. Included was the derivation of the Poisson distribution.

The relationship between pressure p and volume V at adiabatic change of state went as a Poisson law in the physics:

In thermodynamics, also called caloric or thermodynamics, we speak rather of the Poisson equations:

It is (often also called κ ) γ the so-called adiabatic.

After Poisson and the Poisson's ratio is named. It indicates the ratio in which the longitudinal strain ε and the simultaneously occurring Poisson each other εq when a rod is subjected to train. The Poisson's ratio, also known as Poisson's ratio, is between 0 and 0.5 ordinary materials.

As a mathematician Poisson worked in many fields, including differential geometry, calculus and probability theory. Several mathematical concepts associated with his name, such as Poisson's equation, Poisson integral formula, Poisson kernel, Poisson distribution, Poisson's equation, Poisson's ratio and Poisson bracket. In total, he has published over 300 works.

After the laws of the deviation of Matthew Flinders had been found, Poisson Represent presented in mathematical form