text: can anybody explain the two slot experiment?   i demonstrates the duality of wave/particle beahviour that characterises the universe.  it is easier to do with electrons.  if you take two slits, and shine a light at them you will see a diffraction pattern beyond the slits, because the light waves alternately interfere constructively and destructively.   the same happens with electrons. which shows that they behaves like waves.  but with electrons, you can arrange to fire them one at a time at the slits. so how on earth can they interfere? but the pattern seen to develop over time is precisely what is expected with the wave theory.