Nuclear Physicist and Professor Jim Al-Khalili explains Schrödinger's infamous Schrodinger's Cat gedankenexperiment in this excerpt from BBC Four's "Atom" documentary.<br /><br />The gedankenexperiment (thought experiment) has proved to be very useful in quantum theory. Physicists often conduct thought experiments prior to an actual experiment or when a particular physical experiment is impossible to conduct. (It was Einsteins gedankenexperiment of chasing a light beam which resulted in Special Relativity theory.)<br /><br />Published by Schrödinger in the mid-1930s to explain wave function collapse in relation to large objects, Schrodinger's Cat experiment<br />presents a paradox which demonstrates that observation itself affects an outcome - because an "outcome" does not exist until it is observed.