Picture of Werner Heisenberg Courtesy of The Bettmann Archive

Werner Heisenberg was a German physicist who lived between 1901-1976. He developed new theories in quantum mechanics which agreed with the results of previous experiments.

Heisenberg is most famous for his uncertainty principle, which explains the impossibility of simultaneously knowing an object's position and momentum. However, this principle is only significant for submicroscopic particles such as electrons. Another of Heisenberg's famous theories maintained that a scientist interacts with an object while measuring it, and thus has some affect on it.

Heisenberg also wrote the plans for the first nuclear reactor in Germany and promoted such peaceful uses of nuclear energy.