Joseph Fourier

Joseph Fourier was a French mathematician and physicist. He was born on March 21, 1768, in Auxerre, Burgundy.

Fourier is best known for his work in mathematics. He started the study of Fourier series. This later grew into Fourier analysis and harmonic analysis. These ideas help solve many problems in science and engineering.

His work has been used to understand heat transfer and vibrations. Two important ideas are named after him: the Fourier transform and Fourier’s law of conduction.

Besides mathematics and physics, Fourier also discovered the greenhouse effect. This helps explain how Earth’s atmosphere traps heat from the sun.

He lived until May 16, 1830. His discoveries are still important today in many areas of science and technology.

Biography

Joseph Fourier was born in 1768 in Auxerre, France, the son of a tailor. When he was nine, he lost his parents. He was educated by a local religious group and later taught mathematics in the army. During the French Revolution, he helped his community and was briefly jailed but later became a teacher at a famous school.

Fourier traveled with Napoleon to Egypt in 1798, where he gave advice and helped set up a research institute. After returning to France, he became the leader of a region near Grenoble and worked on building roads. It was here that he started studying how heat moves through solids. Later, he became an important leader in the French Academy of Sciences. Fourier never married and passed away in 1830 after some health problems. He was buried in Paris, and his name is written on the Eiffel Tower today.

The Analytic Theory of Heat

In 1822, Fourier shared his big ideas about how heat moves in his book The Analytical Theory of Heat. He used a rule from Newton about how heat moves between things that are close in temperature.

In his book, Fourier made three big discoveries. First, he showed that math can describe things that change suddenly, using special patterns with sines. Second, he talked about making sure math equations make sense by matching up sizes. Third, he created a special math rule to explain how heat spreads out, which is still taught today.

His work helped other mathematicians develop new theories.

Roots of polynomials

When Joseph Fourier was young, he found a special way to figure out how many positive answers a math problem could have. Later, he worked on a hard math problem about finding the real answers to equations with many parts, but he didn’t finish it. Another scientist, Claude-Louis Navier, shared Fourier’s work in 1831 after he passed away. Fourier’s ideas were new and important, especially a big rule he shared in 1820. Another mathematician, François Budan, had shared similar ideas a little earlier, in 1807 and 1811. The full answer to this problem was finished in 1829 by Sturm.

Discovery of the greenhouse effect

In the 1820s, a scientist named Joseph Fourier tried to learn why Earth is warmer than it should be just from the Sun’s heat. He thought maybe something in our air was trapping heat, like how glass keeps a greenhouse warm. Even though he was not completely right about why, his idea was the first step in learning how Earth’s air helps keep the planet warm.

Works

Here is a list of important works by Joseph Fourier:

• "Sur l'usage du théorème de Descartes dans la recherche des limites des racines". Paris: Firmin Didot Père et Fils. 1822. OCLC (https://search.worldcat.org/oclc/2688081).
  • Théorie analitique de la chaleur (in French). Vol. 1. Paris: Gauthier-Villars. 1888.
• "Remarques Générales Sur Les Températures Du Globe Terrestre Et Des Espaces Planétaires". Annales de Chimie et de Physique. 27: 136–167. 1824a.
• Gay-Lussac, Joseph Louis; Arago, François, eds. (1824b). "Resume theorique des Proprietes de la chaleur rayonette". Annales de Chimie et de Physique. 27. Paris: 236–281.
• Mémoire sur la température du globe terrestre et des espaces planétaires. Vol. 7. Mémoires de l'Académie Royale des Sciences. 1827a. pp. 569–604. Translation by W M Connolley
• Mémoire sur la distinction des racines imaginaires, et sur l'application des théorèmes d'analyse algébrique aux équations transcendantes qui dépendant de la théorie de la chaleur. Vol. 7. Memoirs of the Royal Academy of Sciences of the Institut de France. 1827b. pp. 605–624.
• Analyse des équations déterminées on 30 September 2011. Retrieved 20 April 2011.
• Remarques générales sur l'application du principe de l'analyse algébrique aux équations transcendantes. Vol. 10. Paris: Memoirs of the Royal Academy of Sciences of the Institut de France. 1827d. pp. 119–146.
• Mémoire d'analyse sur le mouvement de la chaleur dans les fluides. Vol. 12. Paris: Memoirs of the Royal Academy of Sciences of the Institut de France. 1833. pp. 507–530.
• Rapport sur les tontines. Vol. 5. Paris: Memoirs of the Royal Academy of Sciences of the Institut de France. 1821. pp. 26–43.