Hans Geiger

Johannes Wilhelm Geiger was born 30 September 1882, a German experimental physicist who would give radiation a voice. He carried out the Rutherford scattering experiments — firing particles at gold foil, expecting them to pass through, watching them ricochet — and in that deflection found proof of the atomic nucleus. Later he invented the Geiger counter, the device that turns ionizing radiation into audible warning. He also performed the Bothe–Geiger coincidence experiment, confirming that energy holds its ground even when light meets particle. His brother Rudolf charted weather and climate; H…