How was the Rutherford modle of the atom discovered by Geiger & Marsden ?
Geiger & Marsden fired alpha particles at gold leaf which had a detector screen behind it. They found that a very small proportion of particles (about 1 in 8000) were deflected through large angles (>90o) while most passed straight through. This lead to the 'Rutherford model of the atom' where almost all of an atoms mass is concentrated in a tiny portion of the atom containing all of an atom's positive charge.