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322
Aristotle
Died with the belief that all materials of earth were not made of atoms but of four elements: Earth, Fire, Water and Air. -
460
Democritus
He discovered atoms and that all matter was made of extremely small particles that could not be divided. BC -
Antoine Lavoisier
He was the first person to make good use of the balance, after a visit with Priestly he began careful study of the burning process and proposed the Combustion Theory which was based on sound mass measurements. -
Joseph Louis Proust
Published the Law of Definite Proportions , which states that a compound is composed of exact proportions of elements by mass, regardless of how they were made. -
John Dalton
He identified the hereditary nature of red-green color blindness and revealed the concept of Dalton's Law of Partial Pressures. He also provided atoms exist by discovering that compounds have a fixed composition. -
Michael Faraday
An English Scientist who studied the fields of electromagnetism and electrochemistry. -
Henri Becquerel
Concluding that atoms could be radioactive and also won the Nobel Prize in Physics for the discovery of Radioactivity. -
J.J. Thomson
He discovered the electron and demonstrated that cathode rays were negatively charged. He studied positively charged particles in neon gas. -
Marie & Pierre Curie
Both are best known for their work in the study of Radioactivity , leading to the discovery of the elements for radium and polonium. -
Max Planck
Discovered energy quanta winning him the Nobel Prize in physics. He also showed that light must be absorbed in descrete amounts. -
Albert Einstein
Formulated the Special Theory Of Relativity, which laid basis for the release of atomic theory. -
Ernest Rutherford
He discovered and designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure. -
Neils Bohr
Proposed a theory for the hydrogen atom based on quantum, that energy is transferred only in certain well defined quantities. -
Robert Millikan
The american experimental physicist honored with the Nobel Prize for Physics for the measurement of the elementary electronic charge and for his work on the photoelectric effect. -
James Chadwick
Awarded the Nobel Prize in Physics for the discovery of the Neutron tracking down evidence of Rutherford's tightly bound proton-electron pair.
