Discovery
Einstein
Biographies
Timeline

1887
HEINRICH RUDOLPH HERTZ (Germany, 1857-1894) discovered the photoelectric effect while verifying the existence of the electromagnetic waves predicted by Maxwell.
1888
WILHELM HALLWACHS (Germany, 1859-1922) showed that only negative charges are emitted in the photoelectric effect.
1891
JOHNSTONE STONEY (Ireland, 1826-1911) introduced the name "electron" for an elementary unit of negative charge in electrolysis.
1895
WILHELM CONRAD ROENTGEN (Germany, 1845-1923) discovered x-rays.  He was awarded the Nobel prize for physics in 1901.
1897
JOSEPH JOHN THOMSON (England, 1856-1940) determined q/m for cathode rays.  He was awarded the Nobel prize for physics in 1906.
1899
PHILIPP EDUARD ANTON VON LENARD (Germany, 1862-1947) showed that photoelectric emission is due to electrons.
1899
JOSEPH JOHN THOMSON (England, 1856-1940) showed that the Edison effect is due to electrons .
1900
MAX KARL ERNST LUDWIG PLANCK (Germany, 1858-1947) introduced the quantum theory of radiation-a revolutionary concept. He was awarded the Nobel prize for physics in 1918.
1902
PHILIPP EDUARD ANTON VON LENARD (Germany, 1862-1947) discovered photoelectric threshold frequency and also that the kinetic energy of photoelectrons is independent of the intensity of the incident light.
1905
ALBERT EINSTEIN (Germany, Switzerland, USA, 1879-1955) completed the statistical theory of Brownian movement, introduced the quantum explanation of the photoelectric effect, and announced the special theory