Schrodinger's Cat

One of the most famous things about Quantum Theory is actually a thought experiment that was done by Schrodinger and much enjoyed by Einstein that seeked to show how absurb quantum theory is if taken literally. However many retorted that this is how the quantum world actually is!

According to the Copenhagen interpretation of quantum mechanics, essentially the world exists in a superposition of possibility states until an observation or measurement is made.

Therefore to show how absurd this is, Schrodinger came up with the thought experiment whereby a cat in a concealed box was both alive and dead if we set up the circumstances such that it could be poisoned or it might be, and only on opening the box was the cat alive or dead, otherwise it was both alive and dead which seems very odd.