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The Alchemists used Aristotle's idea about matter and began to create experiments with his ideas. They also contributed to the theory because of their studies of natural processes. https://healthresearchfunding.org/alchemists-atomic-theory-explained/ -
Plato's cosmology comes from a mathematical discovery by Empedocles. http://abyss.uoregon.edu/~js/glossary/plato.html -
Democritus Said all matter was formed of different types of tiny discrete particles and that the properties of these particles determined the properties of matter. https://www.ccp5.ac.uk/sites/www.ccp5.ac.uk/files/Democritus/Basic/Atheory.html#:~:text=About%20400%20B.C.%20the%20Greek,determined%20the%20properties%20of%20matter. -
Galileo used his telescoped to prove the sun in the middle of the solar system and not the earth. He then creaated a model of the solar system called the Heliocentric model. https://spacecentre.co.uk/blog-post/galileos-telescope-changed-our-view-of-the-solar-system/#:~:text=The%20discoveries%20that%20Galileo%20made,by%20astronomers%20like%20Nicolaus%20Copernicus. -
Boyle Contributed to the atomic theory by his law which states that the volume of gas decreases with increasing pressure and the other way around/vice versa. https://www.bbc.co.uk/history/historic_figures/boyle_robert.shtml#:~:text=It%20is%20Boyle's%20Law%20for,'corpuscular%20theory'%20of%20chemistry. -
Lavoisier found that mass is conserved in a chemical reaction. http://chemed.chem.purdue.edu/genchem/history/lavoisier -
Dalton published his first general account of chemical atomic theory. https://pubmed.ncbi.nlm.nih.gov/18175369 -
John Dalton invented the Billiard Ball Model. He thought atoms were the smallest particles of matter, he saw them as solid, hard spheres, like billiard balls, so he used wooden balls to model them. https://www.ck12.org/chemistry/daltons-atomic-theory/lesson/Daltons-Atomic-Theory-MS-PS/#:~:text=Because%20Dalton%20thought%20atoms%20were,pictured%20in%20the%20Figure%20below.
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Avogadro hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. https://www.sciencehistory.org/historical-profile/amedeo-avogadro -
Jotted down symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table. https://www.newscientist.com/people/dmitri-mendeleev -
Thompson Discovered that atoms were made up of smaller components like neutrons, electrons, and protons. https://www.history.com/this-day-in-history/jj-thomson-announces-discovery-of-electrons -
The Plum Pudding Model is one scientific model of the atom introduced by JJ Thompson. He proposed this after his discovery of the electron. https://www.universetoday.com/38326/plum-pudding-model/ -
They successfully isolate radioactive radium salts from the mineral pitchblende in their laboratory in Paris. https://www.history.com/this-day-in-history/curies-isolate-radium -
Einstein mathematically proved the existence of atoms which helped revolutionize all the sciences through the use of statistics and probability. https://www.ans.org/news/article-969/albert-einstein-and-the-most-elemental-atomic-theory -
Rutherford discovered the atomic nucleus. https://www.aps.org/publications/apsnews/200605/history.cfm -
Bohr proposed a theory for the hydrogen atom, based on a quantum theory. https://www.nobelprize.org/prizes/physics/1922/bohr/facts/ -
Millikan's famous oil drop measured the fundamental unit of electric charge. https://www.aps.org/publications/apsnews/200608/history.cfm -
Moseley published a paper in which he concluded that the atomic number is the number of positive charges in the atomic nucleus. https://www.britannica.com/biography/Henry-Moseley -
Schrödinger formulated a wave equation that accurately calculated the levels of the energy of electrons. https://www.nobelprize.org/prizes/physics/1933/schrodinger/facts/ -
The electron cloud model proposed by Erwin showed people that electrons were no longer seen as moving particles around the nucleus of an atom, so he made an educated guess to where they were. https://www.universetoday.com/38282/electron-cloud-model/#:~:text=One%20such%20example%20is%20the,to%20the%20positions%20of%20electrons. -
Werner Heisenberg developed a key piece of quantum theory. https://www.aps.org/publications/apsnews/200802/physicshistory.cfm -
Chadwick reports his discovery of the neutron.
