Rutherford scattering experiments

Experiments measured how alpha particles scatter from thin metal foil. Their rare large-angle deflections showed that atoms contain a small, dense, positively charged nucleus.

Geiger–Marsden experiment: A 1909 experiment measured alpha-particle scattering from thin gold foil. Geiger and Marsden produced the scattering observations Rutherford later interpreted.
Ernest Rutherford: A physicist who established the nuclear model of the atom and helped found nuclear physics. Rutherford interpreted the scattering results as evidence for a compact nucleus.
Rutherford model: An atomic model placing a compact, positively charged nucleus at the center of the atom. Rutherford proposed this model to explain the observed scattering.
Plum pudding model: J. J. Thomson's model pictured electrons embedded in a spread-out sphere of positive charge. Diffuse positive charge could not account for the observed large-angle deflections.
Rutherford formula: A formula gives the angular distribution of particles scattered by a point Coulomb charge. It predicts how the foil's concentrated charge redistributes alpha particles by angle.
Hans Geiger: A German physicist who developed particle-detection methods and studied radioactivity. Geiger conducted the foil-scattering work with Marsden.
Bohr model: An atomic model in which electrons occupy quantized orbits around a nucleus. Bohr added quantized electron orbits to Rutherford's nuclear atom.
Rutherford model of the atom: A model of the atom with a tiny positive nucleus and electrons surrounding it. It replaced the plum pudding picture, though it could not explain atomic stability.
Coulomb scattering: The deflection of charged particles by the electrostatic force between them. Alpha particles turn sharply when repelled by the nucleus's positive charge.
Ernest Marsden: A physicist who, with Hans Geiger, measured alpha-particle scattering from metal foil. Marsden carried out the measurements that exposed rare backward scattering.

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History of subatomic physicsBroader topic: Large-angle scattering exposed a compact, positively charged atomic nucleus.