Schrödinger's Cat

Schrödinger's cat is a famous paradoxical thought experiment originally described by physicist Erwin Schrödinger. It is created in response to a debate with Albert Einstein about the reality of the Copenhagen interpretation of quantum mechanics. The paradox arises from issues of extrapolating quantum effects to macroscopic systems.

The experiment is usually described as follows:

A cat is completely isolated in a box, no information travels into or out of the box. A detector is set up to detect whether a single electron is on one side of the box or the other. If it detects it on a particular side a poison is released killing the cat, if it is on the opposite side then the poison is not released and the cat lives. Since the system is isolated it exist in a state of superposition where the electron is in both places at once. This essentially means that the cat is both dead and alive at the same time.