History of Atomic Theory continued

  • Henri Becquerel

    Henri Becquerel
    -French physicist who discovered radioactivity through his investigations of uranium and other substances.
    -Realized that some invisible radiation had been emitted from the uranium.
    -He won the Nobel Prize in 1903, along with Marie and Pierre Curie, for his discovery, and the SI unit of radioactivity, the becquerel (Bq), was named after him.
    -His work with radioactive materials, leaving him burned and scarred, may have contributed to his death.
  • Max Planck

    Max Planck
    -Planck's law describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature T.
    -The law is named after Max Planck, who proposed it in 1900. It is a pioneering result of modern physics and quantum theory.
  • Robert Millikan

    Robert Millikan
    -American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electronic charge and for his work on the photoelectric effect.
    -Determined the size of the charge on an electron and determined that there was a smallest 'unit' charge, or that charge is 'quantized.'
    -Experimenting with cathode rays in 1897, J. J. Thomson discovered negatively charged “corpuscles” with a mass about 1,840 times smaller than that of a hydrogen atom.
  • Ernest Rutherford

    Ernest Rutherford
    -Discovered that atoms have a small charged nucleus surrounded by largely empty space, circled by tiny electrons, which became known as the Rutherford model of the atom.
    -The first to split the atom.
    -Rutherford tested Thomson's hypothesis by devising his "gold foil" experiment.
    -Forced to discard the Plum Pudding model, reasoned that the only way the alpha particles could be deflected backwards was if most of the mass in an atom was concentrated in a nucleus.
  • Niels Bohr

    Niels Bohr
    -In 1913, Niels Bohr proposed a theory for the hydrogen atom based on the quantum theory that energy is transferred only in certain well defined quantities.
    - Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted.
  • Erwin Schrodinger

    Erwin Schrodinger
    -Took the Bohr atom model one step further.
    -Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position.
    -This atomic model is known as the quantum mechanical model of the atom.
    -Schrödinger's wave equation came as a result of his dissatisfaction with the quantum condition in Bohr's orbit theory and his belief that atomic spectra should really be determined by some kind of eigenvalue problem.
  • Louis de Broglie

    Louis de Broglie
    -He gained worldwide acclaim for his groundbreaking work on quantum theory. - In his 1924 thesis, he discovered the wave nature of electrons and suggested that all matter have wave properties.
  • Arthur Compton

    Arthur Compton
    -Arthur Holly Compton was an American physicist who won the Nobel Prize in Physics in 1927 for his 1923 discovery of the Compton effect, which demonstrated the particle nature of electromagnetic radiation.
  • Werner Heisenberg

    Werner Heisenberg
    -Heisenberg is best known for his uncertainty principle and theory of quantum mechanics, which he published at the age of twenty-three in 1925.
    -He was awarded the Nobel Prize for Physics in 1932 for his subsequent research and application of this principle.
  • Peter Higgs

    Peter Higgs
    • Proposed the existence of the Higgs boson, a subatomic particle that is the carrier particle of a field that endows all elementary particles. -The Higgs boson particle is so important to the Standard Model because it signals the existence of the Higgs field, an invisible energy field present throughout the universe that imbues other particles with mass. Since its discovery two years ago, the particle has been making waves in the physics community.
  • Murray gell mann

    Murray gell mann
    -American physicist who is credited with the introduction of the concept of quarks.
    -He won the 1969 Nobel Prize for physics for his groundbreaking work on the description and classification of subatomic particles.
    -Physicists Murray Gell-Mann and George Zweig were working independently on a theory for strong interaction symmetry in particle physics.
    - Worked on the Theory of elementary particles.
  • Carlo Rubbia

    Carlo Rubbia
    -Italian particle physicist and inventor who shared the Nobel Prize in Physics in 1984 with Simon van der Meer for work leading to the discovery of the W and Z particles at CERN.