Werner Heinsenberg

   Werner Heinsenberg (1901-1976) was a German physicist, became famous for studies in theoretical atomic physics. He developed the principle of indeterminacy, or uncertainty principle. It states that the position and velocity of an electron in motion cannot simultaneously be measured with high precision. He won the 1932 Nobel prize in physics for founding quantum mechanics, which led to a more precise theory about atoms.
   Older concepts of the quantum theory were based on ideas on how atoms were made. Heisenberg based his theories on the observed frequencies (colors) of light given off by atoms. His theory shows that there is a natural limit to the accuracy of certain kinds of experiments. For example, to find the position of a moving electron, a ray of light must strike it. Because the electron is so small, the light must have a short wave length. Such radiation (a gamma ray) has a high frequency and high energy, which cause it to change the velocity of the electron. So the very means used to determine the position of the electron changes the electron's velocity.
   Heisenberg was born in Wurzburg, and was educated at Munich and Gottingen universities. He taught physics at Copenhagen University in 1926, at Leipzig University from 1927 to 1941, at the University of Berlin from 1941 to 1945, at Gottingen University from 1946 to 1958, and at Munich University since 1958. He became director of the Max Planck Institute for Physics and Astrophysics at Munich in 1958. His works include The Physical Principles of the Quantum Theory (1930) and Physics and Philosophy (1958).