Portrait of Werner Karl Heisenberg (1901-1976), German physicist. A graduate of the University of Munich, Heisenberg is remembered for his Uncertainty Principle. This states that it is impossible to make an exact and simultaneous measurement of both the position and momentum of any given body. This principle revolutionised physics, and Heisenberg was awarded the 1932 Nobel Prize as a result. He later postulated the existence of the strong nuclear force, proved later by Yukawa. After WW2, during which he was forced to work for the Nazis, Heisenberg became director of the Max Planck Institute for Physics at Gottingen.