Discovering new particles:  the birth of particle physics
     Experimental techniques:  making things "visible"
     Two new particles of the 1930s

The cloud on the horizon:  QED's infinities

The physics of nuclei

     The initial model:  protons plus electrons
     And the problems it raised for quantum mechanics
          Electron confinement
          The spectrum of b decay

     Discovery:  the neutron (1932)
     Heisenberg's quantum mechanical nucleus