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Democritus formulated the theory of the atoms: the smallest unit of matter which still retains the identity and properties of that matter.
(Photo source: https://glamuur.ee/wp-content/uploads/2019/05/ERS-17.png) -
Aristotle refuted Democritus, postulated the theory of the four elements: Earth, Air, Fire, and Water; this caused 200 of years of pseudoscience.
(Photo resource: https://www.vectorstock.com/royalty-free-vectors/fire-wind-water-vectors) -
The medieval forerunner to chemistry, alchemy was based on the conversion metals into other substances. The word alchemy comes from the word Khemia, a Greek word meaning Egypt. As the Greek concept of the four elements was merged with Egyptian religion.
(Photo resource: https://www.factinate.com/things/42-dark-facts-medieval-alchemy/) -
A 16th century concept that sought to explain the animating principle behind life that distinguished it from non living matter.
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A theory that describes a combustible element released during combustion.
(Photo resource: http://treetownchem.blogspot.com/2016/02/oxygens-alchemical-origins-phlogiston.html) -
Antoine Lavoisier considered the father of modern chemistry and beheaded during the French Revolution. Lavoisier proved oxygen was responsible for combustion, discovered the law of conservation of mass, and taught that matter could change form but could not be created nor destroyed.
(Photo resource: https://en.m.wikiquote.org/wiki/Antoine_Lavoisier) -
Franklin discovered positive and negative charges in electricity.
(Photo resource: https://en.m.wikipedia.org/wiki/Electric_charge) -
He created The Law of Constant Composition, which states that a chemical compound always contains exactly the same proportion of elements by mass. He also discovered H2O always contains 88.9% O, 11.1% H by mass (Photo resource: http://scihi.org/joseph-proust-and-the-law-of-constant-composition/)
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John Dalton formed the basis to modern atomic theory; Matter is made up of atoms that are indivisible and indestructible, all atoms of an element are identical, atoms of different elements have different weights and different chemical properties, atoms of different elements combine in simple whole numbers to form compounds, atoms cannot be created or destroyed, and when a compound decomposes, the atoms are recovered unchanged.
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A Crookes tube is an early experimental tube invented by William Crookes
(Photo resource: https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/pioneers/william-crookes) -
Thompson continued experimenting on the cathode tube and discovered negatively charged particles he called electrons
(Photo resources: https://www.livescience.com/45590-electrons-have-split-personalities.html) -
Becquerel radioactivity in a uranium ore
(Photo resource: https://www.heart.org/en/news/2019/05/03/regular-low-level-radiation-exposure-raises-high-blood-pressure-risk) -
Marie and Pierre Curie discovered and isolated polonium and radium from uranium ores
Which would later lead to radiation poisoning
(Photo resource: https://www.nobelprize.org/prizes/physics/1903/marie-curie/biographical/) -
Millikan calculated the mass and charge of an electron
(Photo resource: https://m.youtube.com/watch?v=UTdQCZTxkbY) -
Rutherford deduced from his experiments that atoms have a core that was positively charged but were mostly made of empty space
(Photo resources: https://en.m.wikipedia.org/wiki/Ernest_Rutherford) -
He discovered the neutron, a particle with no charge.
(Photo resource: http://business.parkrapids.com/news/details/jimmy-neutron-star-of-nickelodeon-s-popular-animated-series-meet-area-kids-in-park-rapids)
