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Democritus
Greek Philosopher Democritus who was born in Abdera, Thrace, Greece.
He stated "by convention hot, by convention cold, by convention color; but in reality atoms and void" which means how you classify things as hot or cold or which color, but in effect what classifies them are the type of atom and the quantity of void.
Democritus formulated an atomic theory for cosmos. -
Isaac Newtown
Isaac Newton born in England proposed a mechanical universe with small solid masses in motion.
Newton described universal gravitation and the three laws of motion.He showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his theory of gravitation. -
John Dalton
John Dalton born in England was known for his research in atomic theory.
He proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. -
G.J. Stoney
Stoney born in Irish midlands, is most famous for introducing the term electron as the "fundamental unit quantity of electricity".. He proposed that electricity was made of discrete negative particles he called "electrons ". -
J.J. Thomson
Thomson was born in Manchester, UK was famous for his deduction of the electron and for his work on the conduction of electricity in gases.
He is credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer. -
E. Rutherford
Rutherford, born in New Zealand, studied radiations emitted from uranium and thorium and named them alpha and beta
Hediscovered the concept of radioactive half life, proved that radioactivity involved the transmutation of one chemical element to another, and also differentiated and named alpha and beta radiation. -
Max Planck
Max Planck born in Holstein was considered to be the founder of the quantum theory.
Planck used the idea of quanta (discrete units of energy) to explain hot glowing matter. -
Hantaro Nagaoka
Nagaoka born in Japan postulated a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle.
He proposed that electrons revolve around the nucleus, bound by electrostatic forces. -
Albert Einstein
Albert Einstein born in the German Empire was famous for his equation, "E=MC2"
Einstein wrote an article that explained that light absorption can release electrons from atoms, a phenomenon called the "photoelectric effect". -
R.A. Millikan
Millikan, born in USA, idea was his measurement of the charge on the electron using the "falling drop method" and for his work on the photoelectric effect.
He then indicatedc the atomic structure of an electricity since he proved that his measurement of the charge was the same for all electrons. -
H.G.J. Moseley
Henry Gwyn-Jeffreys Moseley,born in Dorset, is famous for his outstanding contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number.
Using x-ray tubes, he determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus". This work was used to reorganize the periodic table based upon atomic number instead of atomic mass. -
Niels Bohr
Bohr, born in Denmark, made foundational contributions to understanding atomic structure and quantum mechanics.
He developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons. -
Paul Dirac
Paul Dirac born in England made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics.
He later formulated the Dirac Equation which describes the behaviour of fermions and which led to the prediction of the existence of antimatter. -
James Chadwick
Chadwick was born in England and was awarded for his discovery of the neutron.
Using alpha particles, he discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron
