500-428 BC - Anaxgoras and Empedocles.
Changes in matter are due to changes in indivisible particles
Changes in matter are due to changes in indivisible particles
484-428 BC - Empedocles. Separated indivisible matter into four elements; earth, water, fire and air.
442 BC - Democritus, a Greek philosopher,
Thinking about matter .
384-322 BC - Aristotle. Gathered all theories up to date and was responsible for formalizing the knowledge into one idea. Aristotle was leery that Democritus’s atoms didn’t account for the great variance of matter.
1785 - Antoine Laurent Lavoisier discovered The
Law of Conservation of Mass (or Matter) in a chemical reaction can be stated thus: In a chemical reaction, matter is neither created nor destroyed. However, philosophical speculation and even some quantitative experimentation preceeded him.
Thinking about matter .
384-322 BC - Aristotle. Gathered all theories up to date and was responsible for formalizing the knowledge into one idea. Aristotle was leery that Democritus’s atoms didn’t account for the great variance of matter.
1214-1294 - Rodger Bacon. Taught that in order to understand the natural universe there must first be observation, allowing for evidence to come from the natural world.
1704 - Isaac Newton.The universe is a mechanical universe with small solid masses in constant motion
Law of Conservation of Mass (or Matter) in a chemical reaction can be stated thus: In a chemical reaction, matter is neither created nor destroyed. However, philosophical speculation and even some quantitative experimentation preceeded him.
1803- John Dalton developed a theory that matter is simply composed of atoms of different weights and is combined in ratios by weight.
1832 - Michael Faraday. Split molecules with electricity by means of electrolysis, developed laws of electrolysis.
1859 -J Plucker. Built the first cathode ray tube, used for gas discharge
1873- James Clerk Maxwell. Magnetic and electric fields filled “empty” space in atoms
1879- Sir William Crookes. Studied the properties of cathode rays and found that they exhibit negative charge and mass.
1890 - Dmitri Ivanovich Mendeleev published The Periodic Table of all known elements.
1895 - Wilhelm Roentgen. Used cathode ray tubes to observe that nearby chemicals glowed and the penetrating rays coming from the cathode ray tube were not affected by magnetic fields. He named these rays, X-Rays.
1896- Henri Becquerel. Discovered that some chemicals spontaneously decompose and give off penetrating rays while working with X-rays and photography paper.
1897- J.J. Thomson. Discovers the electron and used cathode ray tubes to determine the charge to mass ratio of an electron to be 1.759 x 108Coulombs/gram. Found canal rays were associated with a proton, H+.
1898- Marie Skodowska Curie. Named the spontaneous decay process of uranium and thorium to be radioactivity.
1899- Ernest Rutherford. Discovers alpha and beta rays emitting from radium.A
1895 - Wilhelm Conrad Rontgen, German physicist discovers X-rays.
1896- Wilhelm Rontgen, discovers X-rays.
1896 - Henri Becquerel discovers radioactivity.
1896 - Henri Becquerel discovers radioactivity.
1898- Pierre and Marie Curie, discovers
Radiation, energy, and the atom. Also, polonium and radium.
Radiation, energy, and the atom. Also, polonium and radium.
1898 - JJ Thomson discovers electrons.
1900 - Max Planck develops quantum theory and photons.
1900 - Max Planck develops quantum theory and photons.
1905 - Albert Einstein develops the nature of light and energy.
1908 - Robert Millikan measures the charge of a single electron and the structure of an atom.
1909 - Ernest Rutherford known as the father of nuclear physics, developed the theory for the structure of the atom. Discovers the atomic nucleus.
1913 - Neils Bohr developed the Bohr atomic model. Bohr's theory was that electrons have certain amounts of energy. Electrons surrounded the nucleus in rings and they can jump from a level to another. He compared the electron function to the planets orbiting around the sun. The problems with Bohr's theory was that it violated the Heisenberg Uncertainty Principle. The theory considers electrons to have a known radius and orbit.
1918 - Max Karl Ernst Ludwig Planck,
German physicist whose discovery of energy quanta won him the Nobel Prize in Physics.
1920 - Johannes Wilhelm "Hans" best known as the co-inventor of the detector component of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus.
1918 - Max Karl Ernst Ludwig Planck,
German physicist whose discovery of energy quanta won him the Nobel Prize in Physics.
1920 - Johannes Wilhelm "Hans" best known as the co-inventor of the detector component of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus.
1926 - Erwin Shrodinger described how electrons move in wave form, and developed the Schrodinger equation which describes how the quantum state of a system changes with time.
1930 - Enrico Fermi, the "architect of the nuclear age" and the "architect of the atomic bomb", the creator of the world's first nuclear reactor, the Chicago Pile-1. Splits uranium but did not realize it.
1930 - Enrico Fermi, the "architect of the nuclear age" and the "architect of the atomic bomb", the creator of the world's first nuclear reactor, the Chicago Pile-1. Splits uranium but did not realize it.
1931 - James Chadwick discovers the neutron.
1933 - Leo Szilard conceives the idea of using a chain reaction of nuetron collisions with atomic nucleus to release energy considers the possibility of using this to make bombs. This predates the discovery of fission...
1933 - Leo Szilard conceives the idea of using a chain reaction of nuetron collisions with atomic nucleus to release energy considers the possibility of using this to make bombs. This predates the discovery of fission...
- 1934 - Ida Noddack publishes a paper in Zeitshrift fur Angewandte Chemie arguing that the anomalous radioactivities produced by neuron bombardment of uranim may be due to the storm splitting into smaller pieces.
- 1935 - Hideki Yukawa ForMemRS FRSE was a Japanese theoretical physicist and the first Japanese Nobel laureate for his prediction of the pi meson. Published the Theory of Mesons, which explained the interaction between protons and neutrons, and was a major influence on research into elementary particles.
1938 - Otto Hahn, regarded as the father of nuclear chemistry, discovers nuclear fission, along with Lise Meitner. Submitsa paper to Naturwissrnschaften conclusively showing the production of radioactive barium from nuetron irradiated uranium.
1938 - Otto Frisch and his aunt Lise Meitner correctly interpret Hahn's results as evidence that the uranium nucleus had split in two (Fission).
1939 - Niels Bohr publicly announces the discovery of fission at an annual theoretical physics conference at George Washington University in Washington, DC.
1939 -U.S. President Roosevelt receives "The Einstein Letter" warning about the prospect of an atomic bomb.
1939 - Niels Bohr and John A. Wheeler publish a theoretical analysis of fission. This theory implies that uranium-235 is more fissile than U-238, and that the isotope of the undiscovered element 94 with 239 nucleons is also very fissile. These implications are not immediately recognized.
1939 - The first meeting of the Advisory Committee on Uranium in Washington, DC, which was created at President Roosevelt's order. Approved $6,000 for research on preliminary uranium-graphite slow neutron experiments.
1940 - Otto Frisch and Rudolf Peierls, living in the United Kingdom, consider the possibility of fast fission in uranium-235. Based on a theoretical estimate of the fast fission cross section they estimate the critical mass of pure uranium-235 at "a pound or two", and that a large percentage could be fissioned before explosive disassembly. They also estimate the likely effects of the bomb, and possible assembly methods, as well as estimates of the feasibility of isotope separation. Conclude that only one pound of highly enriched uranium is needed for a bomb.
1940 - John Dunning, Manhattan, NY, USA was first direct measurements of the enormous slow fission cross section of uranium-235 .
1950 - Richard Phillips Feynman, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, and top-down nanotechnology.
1938 - Otto Frisch and his aunt Lise Meitner correctly interpret Hahn's results as evidence that the uranium nucleus had split in two (Fission).
1939 - Niels Bohr publicly announces the discovery of fission at an annual theoretical physics conference at George Washington University in Washington, DC.
1939 -U.S. President Roosevelt receives "The Einstein Letter" warning about the prospect of an atomic bomb.
1939 - Niels Bohr and John A. Wheeler publish a theoretical analysis of fission. This theory implies that uranium-235 is more fissile than U-238, and that the isotope of the undiscovered element 94 with 239 nucleons is also very fissile. These implications are not immediately recognized.
1939 - The first meeting of the Advisory Committee on Uranium in Washington, DC, which was created at President Roosevelt's order. Approved $6,000 for research on preliminary uranium-graphite slow neutron experiments.
1940 - Otto Frisch and Rudolf Peierls, living in the United Kingdom, consider the possibility of fast fission in uranium-235. Based on a theoretical estimate of the fast fission cross section they estimate the critical mass of pure uranium-235 at "a pound or two", and that a large percentage could be fissioned before explosive disassembly. They also estimate the likely effects of the bomb, and possible assembly methods, as well as estimates of the feasibility of isotope separation. Conclude that only one pound of highly enriched uranium is needed for a bomb.
1940 - John Dunning, Manhattan, NY, USA was first direct measurements of the enormous slow fission cross section of uranium-235 .
1950 - Richard Phillips Feynman, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, and top-down nanotechnology.
1951 - Glenn Seaborg, many discoveries of the transuranium elements, as well as many advances in nuclear medicine, including the development of I-131 for thyroid disease.
1964 - Murray Gell discovers Elementary particles smaller than the atom.
Sources:
1986 - Heinrich Rohrer , Gerd Binnig, & Ernst Ruska. who shared the 1986 Nobel Prize in Physics with for the design of the scanning tunneling microscope ( STM).
* Atomic Heritage
* Wikipedia
* //www.timetoast.com/timelines/10-famous-atomic-scientists
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