In physics, Schrödinger's cat is a thought experiment in which a cat is trapped in a box with a particle that has a 50-50 chance of decaying. If the particle decays, the cat dies; otherwise, the cat lives. Confusing much? Maybe Astrophysicist Paul Sutter explaining it will help! It's a 50-50 chance.
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00:00 As far as we can tell in the subatomic world, everything is just so ridiculously and frustratingly
00:06 random.
00:08 You look at an electron and sometimes you look at it and it'll have a spin pointing
00:12 up and the next time you look at it, it'll have a spin pointing down.
00:16 And you're like, can't you just pick one?
00:18 Why do you have to be both?
00:20 Why do you have to keep flipping back and forth?
00:23 I'm Paul Sutter and this is Paul Explains the show where I, you know, explain.
00:30 The whole machinery of quantum mechanics is designed to translate the probabilities of
00:39 what you might measure when you go to make an observation.
00:44 In the case of an electron spin, the language that we use in quantum mechanics goes something
00:50 like this.
00:52 The spin of the electron is in a superposition of both spin up and spin down states.
01:00 And then when you go to measure it, something happens and it chooses one of those states
01:05 and that's what you actually measure.
01:08 But some of the founders of quantum mechanics didn't really like how this was being described.
01:15 One of those people was Erwin Schrodinger, one of the founders of quantum mechanics.
01:20 He looked at this example, this language, and developed a thought experiment to show
01:26 just how lame this language is.
01:29 He said, what if you put a cat in a box, you close the lid and you put some radioactive
01:34 element in there and just say that there's a 50/50 chance that the radioactive element
01:41 will decay, it'll poison the cat and it will kill the cat.
01:45 But there's a 50% chance that it won't decay, nothing bad will happen and the cat will live.
01:50 Now, as long as you have that box closed, you don't know what's going to go on.
01:56 You don't know if the cat is alive or dead.
01:59 And then you open up the box, you perform your measurement and you see either a dead
02:03 cat or an alive cat.
02:06 Classically, non-quantum mechanically, we would think that at some point the cat might
02:12 or might not die.
02:14 But our observation of it, our measurement of it has absolutely nothing to do with what's
02:19 going on inside the box.
02:21 Either the cat is dead or it is alive, we just haven't found out yet.
02:28 But Schrodinger pointed out that in quantum mechanics, the way we're supposed to think
02:34 about it is that the cat is both dead and alive.
02:40 It exists in the quantum superposition of deadness and aliveness.
02:46 And when we open up the box, that is the moment of the choice.
02:52 That is the moment of the cat becoming dead or becoming alive.
02:57 But until we open up the box, it is both dead and alive.
03:02 And Schrodinger said, "This sounds really dumb.
03:06 Do you actually expect us to believe this when it comes to quantum mechanics?"
03:11 And everyone else who was working on quantum mechanics said, "Yes."
03:17 How do you wrap your mind around this?
03:20 Well, maybe you don't have to.
03:22 Maybe reality is just weird and we should leave the cats alone.
03:28 Meow.
03:29 [Music]
03:35 (cash register dings)