What was inside the atom as early as1900?
Rutherford`s Gold foil experiment was probably the most important. A very elegant experiment his research students Geiger and Marsden measured how much deviation an alpha particle moved from a path. A beam of alpha particles, generated by the radioactive decay of radium, was directed normally onto a sheet of very thin gold foil. The gold foil was surrounded by a circular sheet of zinc sulfide (ZnS) which was used as an indicator. The ZnS sheet would light up when hit with alpha particles. Under the prevailing plum pudding model, the alpha particles should all have been deflected by, at most, a few degrees. However they observed that a very small percentage of particles were deflected through angles much larger than 90 degrees. From this observation Rutherford was able to observe and deduct the central structure of the atom Nice Pics here: http://en.wikipedia.org/wiki/Rutherfords… Then Bohr managed to write about the
