I came across this experiment which was not actually carried out and it made my head ache. It was a thought to interpret quantum mechanics. Heavy for a topic? Yes, but the arguments that transpired after this cat-in-the-box experiment seemed pointless. An excerpt from this page tells:
In the early 1930’s Erwin Schrödinger published a way of thinking about the circumstance of radioactive decay that is still useful. We imagine an apparatus containing just one Nitrogen-13 atom and a detector that will respond when the atom decays. Connected to the detector is a relay connected to a hammer, and when the atom decays the relay releases the hammer which then falls on a glass vial containing poison gas. We take the entire apparatus and put it in a box. We also place a cat in the box, close the lid, and wait 10 minutes.
The answer according to quantum mechanics is that it is 50% dead and 50% alive.
I think it is not common sense to think that the cat is 50% dead AND 50% alive. It can EITHER be dead or alive. That is a more acceptable occurrence to me because how can a cat be dead and alive at the same time?
Enough of these. Common sense does not apply to some sciences I guess.