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Period: 400 to
Atom
BC 400 -
410
Democritus Atom (circa 470 BC)
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470
Democritus (circa 470 BC)
Democritus said that all matter is made up of tiny, indivisible particles called atoms. These atoms were completely solid and were eternally in motion. He also stated that every different type of atom differs slightly.Democritus was admired by Aristotle. -
Antoine Lavoisier
Antoine-Laurent de Lavoisier (also Antoine Lavoisier after the French Revolution; 26 August 1743 – 8 May 1794; French pronunciation: [ɑ̃twan lɔʁɑ̃ də lavwazje]) was a French nobleman and chemist central to the 18th-century Chemical Revolution and a large influence on both the histories of chemistry and biology.[1] He is widely considered to be the "Father of Modern Chemistry."[2]
It is generally accepted that Lavoisier's great accomplishments in chemistry largely stem from the fact that he chan -
John Dalton
Dalton compounded all the work of Lavoisier and Democritus into one, single atomic theory. This theory stated that all matter is made of indivisible and indestructible atoms, all atoms of a given element are identical, compounds are combinations of elements (atoms), and a chemical reaction is merely a rearrangement of atoms.Date Adopted: 1803Dalton built off the works of Lavoisier and Democritus. -
John Dalton Atomic Model
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Henri Becquerel
Henri Becquerel discovered radioactivity in his research of uranium and other materials. This helped to show what happened when atoms were affected and observed.Date Adopted: 1896
Becquerel shared a Nobel Prize with the Curies. -
J.J. Thomson
Sir Joseph John "J. J." Thomson, OM, FRS[1] (18 December 1856 – 30 August 1940) was a British physicist. In 1897, Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, and thus is credited with the discovery and identification of the electron. Thomson is also credited with finding the first evidence for isotopes of a stable (non-radioactive) element in 1913 as part of his exploration into the composition of canal rays (positive ions) and with the inv -
Max Planck
With the completion of his habilitation thesis, Planck became an unpaid private lecturer in Munich, waiting until he was offered an academic position. Although he was initially ignored by the academic community, he furthered his work on the field of heat theory and discovered one after another the same thermodynamical formalism as Gibbs without realizing it. Clausius's ideas on entropy occupied a central role in his work. -
Marie and Pierre Curie
Pierre and Marie Curie are best known for their pioneering work in the study of radioactivity, which led to their discovery in 1898 of the elements radium and polonium. Marie Curie, born Maria Sklodowska in Warsaw, Poland, on Nov. 7, 1867, d. July 3, 1934, spent many impoverished years as a teacher and governess before she joined her sister Bronia in Paris in order to study mathematics and physics at the Sorbonne, earning degrees in both subjects in 1893 and 1894. In the spring of the latter yea -
James Chadwick
Name: James Chadwick discovered the neutrally charged neutron, the discovery that ultimately led to the atomic bomb. He enhanced Bohr’s model by adding neutrons to the nucleus.Date Adopted: 1931Chadwick studied under Rutherford at Manchester College and Cambridge. -
Plum Pudding Atom (Thomson)
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Planetary Atom (Rutherford)
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Bohr Atom
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Electron Cloud Atom (Heisenberg)
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Aristotle (384 BC)
Aristotle (Ancient Greek: Ἀριστοτέλης [aristotélɛːs], Aristotélēs) (384 BCE – 322 BCE) was a Greek philosopher born in Stagirus in 384 BCE. His father, Nicomachus died when Aristotle was a child and he lived under a guardian's care. At the age of eighteen, he joined Plato’s Academy in Athens and continued to stay until the age of thirty-seven, around 347 BCE. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, gover
