Quantum Mechanics 3:9  Quantum Mechanics 4:9 » 
Quantum MechanicsThe Uncertainty Principle 

Heisenberg made one more fundamental and longlasting contribution to the quantum world – the uncertainty principle. He showed that quantum mechanics implied that there was a fundamental limitation on the accuracy to which pairs of variables, such as (position and momentum) and (energy and time) could be determined. This flew in the face of the traditional wisdom of determinism carried over from Laplace's times. If a 'large' object with a mass of, say, 1g has its position measured to an accuracy of 1, then the uncertainty on the object's velocity is a minute 10^{25} m/s. The uncertainty principle simply does not concern us in everyday life. In the quantum world the story is completely different. If we try to localize an electron within an atom of diameter 10^{10} m the resulting uncertainty on its velocity is 10^{6} m/s! 


Related Laureate 

The Nobel Prize in Physics 1932  Werner Karl Heisenberg »  