Arthur Compton
Arthur Holly Compton (September 10, 1892 - March 15, 1962) won the Nobel Prize in Physics (1927) for discovery of the effect named after him.Around 1913, Compton devised a demonstration method for the Earth's rotation. In 1918, Compton studied X-ray scattering. In 1922, Compton found that X-rays wavelength increases due to scattering of the radiant energy by "free electrons". Scattered quanta have less energy than the quanta of the original ray. This observation furthers the "particle" concept of electromagnetic radiation. Compton also developed the method for observing at the same instant individual scattered X-ray photons and the recoil electrons (developed with A. W. Simon). In Germany, W. Bothe and H. Geiger independently form a similar method.