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The Atomic Theory
John Dalton in 1808 published his atomic theory, in which he said that an atom is made of tiny indivisible particles. He also said that the atoms of different elements had different weights. -
The Dynamo
The English Michael Faraday invented the dynamo, which conversed the mechanical movements into electrical impulses. The old bicycles used to have a dynamo, -
The Anesthesia
It was the dental doctor Horace Wells who began using nitrous oxide as an anesthetic, after having seen it use the self-titled professor and chemist Gardner Q. Colton in his shows, which consisted of administering this gas to volunteers from the public. -
The Radioactivity
Radioactivity was discovered in 1896 by the French scientist Henri Becquerel while working with phosphorescent materials. These materials glow in the dark after exposure to light, and he suspected that the glow produced in cathode ray tubes by X-rays might be associated with phosphorescence. -
The Aspirin
In 1897, the young German chemist Felix Hoffmann discovered one of the substances that relieved the most headaches in the world, acetylsalicylic acid.
He began working in the Bayer Company chemistry laboratory in 1894. It was there, while working with another substance, that he managed to get acetylsalicylic acid in a chemically pure and stable form. The substance was shown to have analgesic, antipyretic and anti-inflammatory effects. In 1899, Bayer Company released it under the name Aspirin.
