Phlogiston

Définitions de « phlogiston »

Phlogiston - Nom commun

• (Chimie, Histoire) Substance hypothétique, incolore et inodore, censée être contenue dans les corps combustibles selon la théorie de la phlogistique.

  Le phlogiston, cette substance invisible et inodore que l'on prétendait autrefois contenue dans tout corps susceptible de brûler, n'est finalement qu'une hypothèse fumante de l'histoire de la chimie.

Évolution historique de l’usage du mot « phlogiston » depuis 1800

Citations contenant le mot « phlogiston »

• phlogiston

• Vous avez raison : les "vérités de science" ne sont ni absolues ni définitives. Certaines finissent même par devenir tout à fait fausses. Par exemple, la théorie du phlogistique, qui postulait au XVIIe siècle que la combustion d’un corps consistait en l’émission par ce corps d’un fluide, le phlogiston, a été invalidée par Lavoisier au XVIIIe siècle. Le phlogiston n’existe pas. Mais d’autres "vérités de science", sans être démenties, peuvent présenter au fil du temps un visage changeant.

• I find myself in a kind-of modern version of the phlogiston story with my research into artificial general intelligence. I swim against the tide of the received view – that is, a position that is taken for granted without apparent need for criticism.

• In the late eighteenth century, Antoine-Laurent de Lavoisier discovered fire.” This is how the futurist and artificial intelligence researcher Eliezer Yudkowsky described it, and he’s not far off the mark. Through much of the 18th century, the dominant explanation of combustion was known as the phlogiston theory. Phlogiston theorists held that one of the basic building blocks of matter is a substance called phlogiston, which functions as elemental fire. Combustible substances are made up of phlogiston and a “calx” (residue). When something burns, phlogiston is released until only the calx remains.

• All this speculation seems questionable to me, but there may still be something to it: Obviously some clinical experiences exist that have led people to follow this idea along so much (which doesn’t mean it’s true: phlogiston was widely accepted in physics for centuries also).

• In 1774, English polymath Joseph Priestley proved that the air we breathe is not a single elementary substance but a mixture of gases, and one of the gases he discovered was crucial for the presence of flame. He believed he had found the substance in the air that absorbed the phlogiston and that was therefore responsible for the existence of flame. Because it had yet to absorb any phlogiston, he called this substance dephlogisticated air.

• It was Lavoisier’s obsession with weighing the reactants and products of a reaction that really turned the phlogiston theory on its head. When a substance burned in air, he found, it increased in mass rather than decreased as phlogiston theory predicted. Lavoisier coined the term ’oxygen’ to describe the part of the air that combines with a combustible substance when it burns. 

Traductions du mot « phlogiston »

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