Travel along our timeline to see a number of important discoveries about the electron and the atom Electron discovered by J J Thomson Splitting the atom: the new alchemy Cloud chamber The atom - according to Rutherford and Bohr Waves or particles? Counting particles The neutron The positron The first atom smashers The cyclotron A new kind of radioactivity Atom tracks Particle physics New particles Even bigger machines © Science Museum (www.nmsi.ac.uk/) and Institute of Physics (www.iop.org/), 1997. All rights reserved. Designed by the Electronic Publishing Group of Institute of Physics Publishing.