From “Minute Physics”. ( YouTube / Nebula )

Full video: https://www.youtube.com/watch?v=IOYyCHGWJq4
I’m sure you’ve heard some version of this famous thought experiment: you put a cat in a bunker with some unstable gunpowder that has a 50% chance of blowing up in the next minute, and 50% chance of doing nothing.
So until we look in the bunker, we don’t know whether the cat is dead or alive, and when we do look, it is either dead or alive.
But if we repeat the experiment enough times with enough cats and bunkers and gunpowder, we’ll see that half the time kitty survives, and half the time kitty goes bye-bye.
The quantum mechanical interpretation is that before we look, the cat is in a superposition – it’s both dead AND alive – and our act of looking forces nature’s decision.
So our curiosity kills the cat.
But what about the cat’s perspective?
Well, the cat either sees the gunpowder explode, or not – so inside the bunker we actually have these two possibilities: "the powder exploded and the cat saw it explode" or "the powder didn’t explode and the cat didn’t see it explode".
There’s no option: "the powder exploded and the cat didn’t see it explode" – so the cat’s reality becomes entangled with the outcome of the experiment!
And it’s our observation of the experiment that forces nature to "collapse" to one option or the other.

Minute Physics provides an energetic and entertaining view of old and new problems in physics — all in a minute!
Created by Henry Reich