Phys.org September 7, 2012

This is a general method for measuring the precision and disturbance of any system. The system is weakly measured before the measurement apparatus and then strongly measured afterwords. Credit: Lee Rozema, University of Toronto Werner Heisenberg’s uncertainty principle, formulated by the theoretical physicist in 1927, is one of the cornerstones of quantum mechanics. In its most familiar form, it says that it is impossible to measure anything without disturbing it. For instance, any attempt to measure a particle’s position must randomly change its speed.

Read more at: http://phys.org/news/2012-09-scientists-renowned-uncertainty-principle.html#jCp