The Nobel Prize in Physics 1905
Philipp Eduard Anton von Lenard
Born: 7 June 1862, Pressburg (now Bratislava), Hungary (now Slovakia)
Died: 20 May 1947, Messelhausen, Germany
Affiliation at the time of the award: Kiel University, Kiel, Germany
Prize motivation: "for his work on cathode rays"
Field: atomic physics
Experiments at the end of the 19th century with cathode rays, radiation emitted in a low pressure glass tube when a voltage is applied between two metal plates, led to the discoveries of the electron and of X-rays. In crucial experiments by Philipp Lenard, started in 1893, the glass tube was equipped with a thin aluminium window making it possible to study the radiation outside the glass tube. One could show that the radiation was not electromagnetic.