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Event Summary 

1921: Stern & Gerlach demonstrate spatial quantization and the necessity of 
the intrinsic magnetic moment of the electron
Albert Einstein (See 1905 & 1915) receives Nobel Prize in physics 
(theoretical contributions and the photoelectric effect)
1922 Niels Bohr (See 1913) receives Nobel Prize in physics (structure of and radiation from atoms)
1923 Compton demonstrates change in X-ray wavelength due to scattering from electrons
(The Compton Effect)
Robert Andrews Millikan (See 1916) receives Nobel Prize in physics 
(electron and photoelectric effect)
1924 Zworkin Invents the Picture Tube
de Broglie postulates the wave behavior of particles
Karl Manne Georg Siegbahn receives Nobel Prize in physics (X-ray spectroscopy)
1925 Pauli proposes the Exclusion Principle
Goudsmit & Uhlenbeck introduce the concept of intrinsic angular momentum (spin)
Heisenberg proposes matrix mechanics (Quantum Mechanics)
James Franck and Gustav Hertz receive Nobel Prize in physics (electron-atom scattering)
1926 Schrödinger introduces wave mechanics (Quantum Mechanics)
Born establishes statistical (probabilistic) interpretation of Schrödinger's wave functions
Jean Baptiste Perrin receives Nobel Prize in physics (sedimentation equilibrium)
1927 Black Invents the Negative Feedback Amplifier
Heisenberg develops uncertainty principle
Independantly, Davisson & Germer and G.P. Thompson demonstrate wave nature of electrons
Arthur Holly Compton (See 1923) receives Nobel Prize in physics (the Compton Effect)
Charles Thomson Rees Wilson receives Nobel Prize in physics 
(visualization of path of charged particles via vapor condensation)
1928 Dirac Proposes relativistic quantum theory
Sir Owen Willans Richardson receives Nobel Prize in physics 
(thermionic phenomena esp. Richardson's Law)
1929 Hubble reports evidence of expansion of the universe
Prince Louis-Victor de Broglie (See 1924) receives Nobel Prize in physics 
(wave nature of electrons)
1930 First World Cup Soccer Match
Sir Chandrasekhara Venkata Raman receives Nobel Prize in physics (Raman effect)