Origins & Early Life

Johannes "Hans" Wilhelm Geiger (30 September 1882 – 24 September 1945) was a German experimental physicist. He is known as the inventor of the Geiger counter, a device used to detect ionizing radiation, and for carrying out the Rutherford scattering experiments, which led to the discovery of the atomic nucleus. He also performed the Bothe–Geiger coincidence experiment, which confirmed the conservation of energy in light-particle interactions. He was the brother of meteorologist and climatologist Rudolf Geiger.

Pivotal Works & Achievements

Johannes Wilhelm Geiger was born on 30 September 1882 in Neustadt an der Haardt (now Neustadt an der Weinstraße), Kingdom of Bavaria, German Empire, the eldest of five children of Indologist Wilhelm Geiger. Geiger studied physics at LMU Munich and the University of Erlangen (now the University of Erlangen–Nuremberg). In 1906, he received a Doctor of Philosophy from Erlangen for a thesis on electric discharges through gases, supervised by Eilhard Wiedemann. After graduating, Geiger received a fellowship to the Victoria University of Manchester, where he worked as an assistant to Arthur Schuster. In 1907, after Schuster's retirement, Geiger began...

Enduring Legacy & Impact

The historical impact and works continue to influence the modern world.

Contemporary Figures & Related Historical Timelines

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• 1882 Historical Timeline & Archive — Explore world events and figures from 1882
• September 30 (09-30) On This Day — Historical birthdays and events on September 30
• 1945 Historical Timeline & Archive — Explore world events and figures from 1945
• September 24 (09-24) On This Day — Historical events and memorials on September 24