Ernest Rutherford compared one of his discoveries to firing an artillery shell at tissue paper and watching it bounce back. This episode follows the farmer’s son from Brightwater, New Zealand, who won scholarships to Cambridge’s Cavendish Laboratory and went on to become the architect of modern atomic theory.

We trace his early radio receiver and the race with Marconi, his work with Frederick Soddy at McGill on radioactive decay and half-life, his challenge to Lord Kelvin’s estimate of the Earth’s age, the 1909 gold foil experiment, his wartime sonar research, the discovery of the proton, and his leadership of the Cavendish team that split the atom, along with his famous dismissal of atomic energy.

• How he classified alpha, beta, and gamma radiation by their penetrating power
• The coin-flip analogy that explains radioactive half-life
• How radioactive heat undermined Kelvin’s calculation of the Earth’s age
• Why the gold foil experiment killed the plum pudding model and revealed the nucleus
• How missing mass led to the prediction of the neutron, later found by James Chadwick