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440 BCE
Plato
Aristotle's partner, he found out matter was always there, infinite, in every form, and all around us. Atoms are what make up matter. He believed in the four elements (Air, water, earth, and fire). https://www.ck12.org/section/evolution-of-the-atomic-model/
My amazing science teacher Ms.Shick. -
Period: 438 BCE to
Learning of Atoms and the people who discovered it.
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400 BCE
Democitrus
Is a Greek Philosopher, said that all matter was formed of different types of little discrete particles and that the properties of these particles are also determined properties of matter. Observed that compounds and that they always contain same elements in same proportions. This is related to atoms because compounds are made up of them. https://www.ucl.ac.uk/~ucfbasc/Basic/Atheory.html -
500
The Alchemists
Believed all metals were made from 2 principles- mercury and sulfur, both had different properties. This related to atoms because metals are made of atoms. These people were Arabian scientist. The time period extends to 1700 A.D. https://uwaterloo.ca/chem13-news-magazine/february-2019/feature/ancients-and-alchemists#:~:text=The%20alchemists%20believed%20that%20all,body%20and%20calcination%20(rusting). -
Robert Boyle
He expressed the "inverse relationship" that exists within gases' pressure and volume. This relates to atoms because gas is a state of matter, and matter has atoms. He was the 14th child and 7th son. https://www.britannica.com/biography/Robert-Boyle#ref218470 -
Antone Lavoiser
Expressed the law of conservation of mass. Stated mass is a remote property that is neither made nor demolished by chemical reactions or physical transformations. This is related to atoms because you can't destroy atoms so they vanish. https://www.sutori.com/en/story/atomic-model-timeline—qFp8aDM24zgcAtga3oiJ48fi -
John Dalton
Stated that all matter was made of invisible and indestructible, atoms that have distinct masses and properties, mix of which determined physical nature of their essential elements. His model "Billiard Ball Model" was of an atom. Had concepts of atomic nucleus, and electrons were undiscovered. Born in a quaker family. https://royalsociety.org/topics-policy/diversity-in-science/scientists-with-disabilities/john-dalton/#:~:text=His%20subsequent%20work%20on%20the,modern%20theory%20of%20the%20atom -
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Amedeo Avogadro
Was born in Italy and made right a molecular formula. Said that equal volumes of gasses at the same temperature and pressure, contain same # of molecules. Molecules are made up of atoms. https://www.britannica.com/biography/Amedeo-Avogadro -
Dimitri Mendeleev
Made the periodic table, putting atomic numbers and mass. He had 17 kids. https://www.newscientist.com/people/dmitri-mendeleev/#:~:text=On%2017%20February%201869%2C%20Russian,the%20periodic%20table. http://hobart.k12.in.us/ksms/PeriodicTable/mendeleev.htm#:~:text=His%20mother%2C%20Maria%20Dmitrievna%20Mendeleev,by%20opening%20a%20glass%20factory. -
Pierre and Marie Curie
Found powerfully radioactive elements Polonium and radium. Discharged the conversion of ions by preventing rays by specific atoms. They both won the Nobel prize for physics. https://www.britannica.com/science/atom/Discovery-of-radioactivity https://www.britannica.com/biography/Marie-Curie -
JJ Thompson
Found atom as a sphere of positive matter where electrons were positioned by forces. He discovered electrons. His "Plum Pudding Model" showed that electrons had been stuck in a uniform sphere of positive charge. First name is Joseph John. https://sciencehistory.org/education/scientific-biographies/joseph-john-j-j-thomson/ -
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Albert Einstein
Proved that atoms were real, and revolutionized all science. Said any liquid is structured of molecules. He was "the father of modern physics". He explained the equivalency of mass and energy, e=mc^2. This is related to atoms because liquid is a state of matter, and matter is made up of atoms. -
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Robert Milikan
Discovered about the elementary charge, which is a charge from 1 electron. He was born in Illinois in 1868. https://study.com/learn/lesson/robert-millikan-biography-atomic-theory.html#:~:text=Millikan's%20work%20proved%20that%20electrons,mass%20of%20a%20single%20electron. -
Ernest Rutherford
Said atom was tiny, dense, and positively charged. Stated mass of atom is contained in its nucleus. He died when he was 66 years old. https://www.primaryconnections.org.au/themes/custom/connections/assets/SBR/data/Chem/sub/atom2/atom2.htm#:~:text=In%201911%2C%20Rutherford%20described%20the,planets%20revolving%20around%20the%20Sun. -
Henry G. J. Mosely
Showed the major properties of an element are based on atomic number, not atomic weight. Stated the relationship between atomic number and charge of atomic nucleus. He went to Trinity college. https://www.britannica.com/biography/Henry-Moseley -
Niels Bohr
Made a theory for the hydrogen atom, built on quantum theory that some physical quantities take any discrete values. Electrons move in nucleus only in orbits. His model was "Solar System Model". It explains that atoms as having a nucleus with a # of electrons in orbits around it. He was born in Copenhagen, Denmark. https://www.nobelprize.org/prizes/physics/1922/bohr/facts/ -
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Erin Schrodinger
His model "Electron Cloud" showed the place where electrons would be in an atom. Electrons were thought to be mobile. He won a physics Nobel prize. https://rinconeducativo.org/en/recursos-educativos/heisenbergs-atomic-model-1927-ad/#:~:text=According%20to%20Werner%20Heisenberg's%20model,that%20surround%20the%20atomic%20nucleus. https://study.com/academy/lesson/electron-cloud-definition-model-theory.html#:~:text=The%20electron%20cloud%20model%20shows,than%20far%20away%20from%20it. -
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Werner Heisenberg
His model was focused on linear power and the place of an electron or other subatomic particles. He said it is not doable to simultaneously predict the equivalency of both variables. This is related to atoms because atoms are made of subatomic particles. He got his name from a German physicist. -
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James Chadwick
His model directed on modeling of all the Atomic nucleus. Enabled not only by protons but also by neutrons. Found where neutron was arranged and made up of a proton and a n electron. He lived for 82 years. https://rinconeducativo.org/en/recursos-educativos/chadwicks-atomic-model-1932-ad/ -
Andrew Harris
Andrew Harris showed in this perfect timeline project, that he is the next famous scientist who learned about atoms.