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400
Democritus: 460-370 BCE
Democritus stated that everything is composed of atoms which are physically, but not geometrically, indivisible; that between atoms, there lies empty space; that atoms are indestructible; have always been, and always will be in motion; that there are an infinite number of atoms, and kinds of atoms, which differ in shape, and size. -
Antoine Lavoisier 1743-1794
The Father of Modern Chemistry. He wrote the Law of Conservation of Matter. He discovered the role of oxygen in combustion, discovered and named oxygen and hydrogen, and helped make the metric system. He wrote the first extensive list of elements. -
John Dalton 1766-1844
He is best known for work in the development of modern atomic theory. He wrote the Law of Multiple Proportions. He stated that compounds are made of elements of multiple proportions. His experiment with gases found that they were made of multiple elements. -
J. J. Thomson 1856-1940
His model "Plum-Pudding" was the most popular model of the time. He is credited with the discovery of the electron, and isotopes. -
Ernest Rutherford 1871-1937
He developed the concept of radioactive half-life, and discovered and named the proton. His theory was that the mass of the atom must be concentrated in a central location with electrons orbiting around it. -
Marie Curie 1867-1934
She was the first women to win a Nobel prize, discovered polonium, and radium which both emitted radiation. -
Max Planck 1858-1947
Created the quantum theory. -
Albert Einstein 1879-1955
Developed the general theory of relativity, and invented the mass-energy equivalence E=mc^2, He determined that a state of dependence in which the existence or significance of one entity is solely dependent on that of another. This theory changed the way scientists thought and led the way for modern pysics theories. He also discovered the Law of the Photoelectric Effect. -
Robert Millikan 1868-1953
He measured the charge of a single electron, and discovered and named cosmic rays. -
Niels Bohr 1885-1962
He made fundamental contributions to understanding the atomic structure and quantum physics. He proposed that electrons are found only in specific levels of energy and explained how electrons give off light (gain or lose energy) -
Arnold Sommerfeld 1868-1951
He pioneered developments in atomic and quantum physics, supervised many Nobel Prize winners and introduced the 2nd quantum number. -
Louis De Broglie 1892-1987
He made groundbreaking contributions to quantum theory, and made the wave-particle duality concept. -
Werner Heisenberg 1901-1976
One of key creators of quantum physics, published his uncertainty principle which he built his philosophy on. Also he made important contributions to the theories of hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic particles. -
Erwin Schrodinger 1887-1961
He stated that electrons were arranged in the region of space that surrounds the nucleus. This represents the Quantum Model of Electrons. He formulated the wave equation, developed formulism and matrix mechanics. -
James Chadwick 1891-1974
He discovered the neutron. He determined that nuclear fission released a neutron. -
The Manhattan Project
The first nuclear bomb is tested.
