Schrödingers Katze 

SUPERPOSITION

The time of  atom’s decay is undetermined, as is its location.

It is in a superposed state. It is simultaneously there and not there.

Schrödingers thought experiment //

In a box, a radioactive element that decays very quickly, a cat and a container with a poisonous substance. It also contains a device with a Geiger counter that would smash the container of the poisonous substance with a hammer as soon as the detector measures that the radioactive element has decayed. The cat would be killed. If I were to open the box before the radioactive atom's decay, the cat would stay alive. As long as I don`t look inside the box the cat could be both – dead and alive.

Who decides?