Coulomb, Charles de

1995/08/02 Azkune Mendia, Iñaki - Elhuyar Fundazioa | Kaltzada, Pili - Elhuyar Zientziaren Komunikazioa

• Biografiak

(1736-1806)

French physicist who joined Angulema on June 14, 1736. As a young man he began to work as an engineer in the Army and, at his request, was sent to work in the West Indies (Martinique). There he worked for nine years in the construction of the fort called Fort Bourbon.

He returned from the Indies and left the army. By then he had a fondness for science within him and began to experiment. When the French Revolution broke out, he decided to retire to the village of Blois to continue working there. The Terror of the Revolution could have had a quiet time for having been in politics.

By then he was famous as a scientist. In 1777 he published on the one hand the first work entitled Studies for the manufacture of imanada needles in the best possible way, and on the other hand he invented the torsion scale that same year. Weight is the force of gravitation on a body, so it could be used to weigh the torsion balance.

The truth is that the English geologist John Michell had already invented a similar balance, but Coulombe did not know and did his work independently.

Coulomb used his precision balance in electricity tests. It placed a small electrically charged sphere at different distances in front of another small charged sphere and with its balance measured the force of repulsion or attraction (depending on whether the electric charges were equal or counterposed). Thus, in 1785 he was able to report his law: the electric force of repulsion or attraction was directly proportional to the product of the electric charges that the spheres had and inversely proportional to the square of the distance between centers of loads. Coulomb's law therefore means that the forces of electric attraction are similar to those found by Newton for gravitation. Since in the atom there are also positive and negative electric charges, the law of Coulomb is of vital importance in its forces of attraction and repulsion.

Priestley, for his part, came to these conclusions a few years earlier and Cavendish also, but Cavendish never published his discoveries and they met fifty years after his death. Coulomb published his discoveries in Mémoires de I'Académie royale des sciences (1785-1789).

Coulomb also published in 1779 the work entitled Theory of simple machines, in which he analyzed friction problems.

In 1789, studying the influence of the Earth's magnetic field on the magnetized needle, he invented the concept of magnetic moment and the theory of polarization.

In honor of Coulomb, the electric charging unit is named after him.

Charles de Coulomb died in Paris on 23 August 1806.