Slide 7 of 18
Gold foil is so maleable that it can be pounded into very thin foils that look like mostly empty space to most nuclear radiation. The results of Rutherford’s famous experiment could be understood only if the gold atoms had a massive nucleus that, if an alpha particle hit it head on, could bounce it straight back.
Rutherford’s quote at lower left is typical of his famous down-to-earth way of describing his physics experiments.
When asked why the electron moves in an atom and the nucleus doesn’t, Rutherford said “When a flea is on an elephant, it’s the flea that jumps, not the elephant.”