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410 BCE
Democritus
He developed the concept of the atom. He believed that everything in the universe was made up of atoms. -
Isaac Newton
Famous for his law of gravitation. Published Philosophae Naturalis Principia Mathematica. This book was widely regarded as one of the most important books in the history of science. -
Antoine Lavolsler
Determined the law of conservation of matter by extensive experimentation. Also named elements Carbon, Hydrogen, and Oxygen. -
Joseph Proust
Determined the law of constant composition, where compounds always contain the same proportion, by mass of elements. -
John Dalton
in 1803 john Dalton revealed the concept of Dalton's law of partial pressures and was studying color blindness, he was actually colorblind and wanted to know how it worked either genetically or in some other form. -
Dmitri Mendeleev
His deepest wish was to find a better way of organizing chemistry. This led to his discovery of the periodic law. He created the Periodic table in 1869 -
George Stoney
He estimated the number of molecules in a cubic millimeter of gas, at room temperature and pressure. Most important scientific work was the conception and calculation of the magnitude of the "atom of electricity." -
Wilhelm Roentgen
Discovered X-ray beams in 1895. He discovered that x-ray beams are produced by the impact of cathode rays on material objects. -
Henri Becquerel
This man newly discovered X-rays in 1896. He discovered radioactivity. -
J. J. Thomson
Discovered the electron in a series of experiments designed to study the nature of electric discharge in a high vacuum cathode-ray. -
Marie Curie
She and help from her partner Pierre Curie discovered radium and polonium in 1898. She had devoted her life to the investigation of radioactivity and was one of very few female scientists. -
Max Planck
Became considered the inventor of the quantum theory in 1900. Made Planck's Law of Black Body Radiation. -
Robert Milikan
Two major achievements: Measuring the charge of the electron in his famous oil-drop experiment and verifying Einstein's prediction of relationship between light frequency and electron energy. -
Ernest Rutherford
Discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei. Received Nobel prize for Theory of Atomic Structure. -
Henry Moseley
Because of his work, the modern periodic table is based on the atomic numbers of the elements. -
Neils Bohr
He developed the Bohr model of the atom in 1913. This model of the atom depicts the atom as a small, positively charged nucleus surrounded by negatively charged electrons that travel in circular orbits around the nucleus. -
Werner Heisenberg
Made foundational contributions to quantum Theory. He is best known for the development of the matrix mechanics formulation of quantum mechanics. -
Erwin Schroedinger
Expanded the idea that electrons behaved as particles and waves, this developed the quantum mechanical model of the atom. -
James Chadwick
He discovered the neutron in 1932. His own research was more focused on radio activity. After Rutherford discovered the proton it seemed that the proton wasn't the only particle in the Nucleus. -
Hideki Yukawa
Had a theory of Mesons (hadronic subatomic particles). This theory explained the interaction of neutrons and protons.
