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Democritus
He claimed that everything is made of atoms, and that they are physically indivisible and between atoms lays empty space. Also those atoms are indestructible and they always have been and always will moving. -
May 8, 1473
Antoine La Voisier
Proved the law of mass around the year. (Law of conservation)- Law of Conservation: Mass cannot be created of destroyed. The mass of the reactants must equal the mass of the products. -
Robery Boyle
He thought that the elements are made of ‘corpuscles’ of different shapes and sizes and that they’re able to organize themselves in different groups that represent different chemical substances. -
Joseph Priestly
He is best remembered for his discovery of the gas that is now known as ‘oxygen’ -
Joseph Proust
Discovered that every pure compound had its own characteristic elemental composition.Also that the ratio of the element never changed even when the mass did. H20 will always have a ratio of 2:1, even if it’s 10g or 100g. -
John Dalton
In 1803 he proposed the ‘Atomic Theory. In which all matter was composed of small indivisible particles –atoms-, atoms of a certain element have different characteristics and weight also three kind of atoms exist: simple, compound and complex. -
Sir William Crookes
Discovered Thallium and noted for his Cathode-ray studies.He continued to work with the Element, but kept it out of the way while he studies it.In 1873 he determined its atomic weight.While studying the element he discovered the use of the Crookes Radiometer- a device that turns light radiation into rotary motion -
Henri Becqueral
Known for discovering a form of radiation that could pass through solid matter, which caused a rush of scientists who rush to study the phenomenon.Radiation given off by uranium metal and its compounds apparently didn’t have anything to do if they were exposed to sunlight. Soon a new form of radiation had been discovered, it was called ‘Radioactivity’ but Marie and Pierre Curie. -
Joseph John (J. J.) Thomson
He discovered the electron with a series of experiments made to study the nature is the electric discharge in a high-vacuum cathode-ray tube.In 1904 he implied that the model of an atom was a sphere of positive matter in which electrons are positioned by electrostatic forces. -
Wilhelm Roentgen
Best known for his invention of the X-Ray in 1895. For the first time the human body could be seen with out cutting one open.It was soon realised that frequent exposure to the x-rays could be harmful. -
Aristotle
Was the first author whose surviving works contained a very detailed and extensive observation of the natural phenomena. First philosopher to get a sound grasp between observation and theory in a scientific method.