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One of my favorite thought experiments. Yes, really. Just one of them!
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It's cat?Really?
Well,They will forget what they done soon, i think.
Google Plus comments are also an interesting thought experiment.
This experiment gets a little more complicated when you factor in the remaining lives of the cat.
I wonder how much more fun it would have been if he had used a wombat. Or maybe a marmoset. :)
It just seems like a lot of over-thinking to me.
I love the idea of the cat being though of as both alive and dead at the same time....yet..
I love this one too! What are some of your other favs?
This presentation makes it seem that ANY time there is a choice or options for what can occur--it becomes a superposition. But this is only true when the option is tied to a quantum event. In the original thought experiment, Schrodinger used radioactive decay to trigger the poison. In his words, "indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation."
It was an attempt to show how messed up quantum mechanics is with how we think of the world. I don't think he hated cats :)

Also check out the double-slit experiment:

A: The cat messes with the gunpowder and so it explodes.

B: The cat messes with the gunpowder and so it does not explode.

Thus you take into account feline behavior.
+Alan Kellogg C: The cat is the reincarnation of MacGyver, escapes the box using the gunpowder, and the observer is left in a state uncertainty indefinitely.
Man, Big Bang Theory always does everything first!
breaking even is top priority period
I tried to explain this to a lady at CFI the other day and she just did not get it.
+Roger White I was going to write the same thing--glad I scrolled through the comments! The video doesn't make a whole lot of sense unless the cat's life/death is tied to a quantum event. Even in Einstein's version of this experiment, the explosives were rigged to atomic decay within the box (a decay of which happens/doesn't happen at same time (aka superpositioned) until it is observed).
I don't get it... I'm lost at "your curiosity kills the cat"...
i reckon d cat wasn't feeded by anyone after Erwin ,so it is very slim n thin.....but here instead of poison a Burger is used....L OL

Minute Physics Videos from Univ of N ....always Gr8
Obviously the collective consciousness of life is observing all factors and therefore the cat only resides in one state and ultimately one universe. 
at four I crossed a major road to see a utility vehicle making a noisy mess only to be run-over coming back..
still does not explain why the many flat-cats which where run-over in later years
+Hajar Susilo Think of it this way. Someone is holding an object behind their back using both hands. You then ask to see what it is and when they bring it around it is in only one hand.

So in the movie when the bunker is closed the cat is both alive and dead simultaneously just as the object was in both hands. When you look inside it forces nature to make a decision so your act of looking inside is like the person bringing the object around using only one hand since it can't be both.
the double slit experiment remains my favorite. One can even reproduce it for not very much money. Its mind boggling. My brain enters a loop whenever I begin thinking about it.
Does it not seem the height of human arrogance that unless I witness something, it must not exist? That my mere glance causes reality to form around me? Can't something exist without my express permission, awareness, or understanding?
+Tyler Brown Yep >*sparkles*< It does not take a person to witness an event for the event to have happened. I never understood people when they asked .. "If a tree falls in the forest and no one hears it, did it make a sound?" I would look at them and ask "Who put what in your food?"
For your mere glance to mean anything, energy has to be shot at an object (to "observe it"--even if we're talking about a single photon), which then affects that object, especially at the quantum scale. It's not arrogance, it's science. And nobody's saying something doesn't exist unless it's observed--the opposite is true in that something can exist in two seemingly opposite states at once (wave/particle duality of light, upspin/downspin of electrons, etc) and the process of observing that "thing" forces that "thing" to be one or the other.
when it is said who is observing us observing the cat, that causes a recursion that can go on to infinity (who is observing the observer of ... of us?) thus it is pointless to even ask. we are simply observing, and making the outcome be decided, we do not need an observer as we are not a part of the experiment.
The observer being unaware of the cat's state doesn't affect the cat's state--it affects the observer's state. I never fucking understood this one. Maybe it works with electrons, but I don't see how it works with cats. There seems to me to be a leap in logic between "from my perspective, the cat exists in a state of superposition" to "from ALL perspectives, the cat exists in a state of superposition."

Also, not be be a dick, but wtf Veronica Belmont, do you really need to call attention to the fact that you are familiar with MORE THAN ONE thought experiment? "One of my favorite thought experiments. Yes, really. Just one of them!" What do you want, a cookie for your wisdom?
+Raphael Ellis The problem is with the video. It's tough to understand the coolness of the experiment because the video does not link the quantum level to the macro level. The "experiment" is meant to demonstrate how weird the quantum world is when its rules are applied to things we can actually see. This is a better video that I show my students: Schrödinger's Cat - Sixty Symbols
Mein Verstand erlebt Verstrickung.
Also, read through the comments to the video I linked, because people do a pretty good job of additional explanation.
Curiosity killed the cat - but satisfaction brought it back! Did the cat come back to life once the experiment was explained to it and it was satisfied with the answer?
You're right, that's a much better video. Thank you! Ok, the part I never understood was that the point of the experiment is to demonstrate how absurd the notion of a superimposed state is when applied to macro level things. I feel a bit stupid now, really, wondering what all those people were doing, trying to prove that a cat was both dead and alive until a human observed it.
как только в наш колхоз! оптоволокно подведут, обязательно посмотрю
excellent for your thought really nice
So, by observing this video, the universe collapsed into the reality of the video running on my computer?
the cat was bound to die or not to and anything we do does not change what will happen to the cat ,so in this equation we are the 'passive variable'
So thats where the phrase "curiosity killed the cat" comes from.... Thanks for that #Youlearnsomethingneweachday
At last I understand.
ditto~! I have a shirt that's even dedicated to it. And I liked how they had Sheldon Cooper apply it to a common personal emotional situation.
hey ... what r u doing .
Makes my brain feel funny... Or, "I can haz funny brainz?"
"This sentence is false."

It is a wonderful thought experiment though. Although this explanation is missing a very important detail:

Originally, it was supposed also to proof how a single atom changing (poison gas , released based on half-time of a radioactive element) can affect large things (like a cat).
I love Sheldon Cooper, I love science. I still think this video is crazy shit. I also think it is the scientists'/philosophers' job to explain why I am wrong. I don't hold out a lot of hope, but I want them to succeed.
It kind of bothers me that, with all the math and self-discipline involved, the scientists that see this as "real" are asking us to believe something hard to stomach:

That reality changes, just because we observe it.

Didn't we all realize the light in the fridge goes off or on, because we use the switch, and not whether we were hungry?
There's no point pickling your brain trying to understand this. The whole point about Schrodinger's thought experiment was that it was a criticism of a particular way of understanding quantum mechanics, the "Copenhagen interpretation". Schrodinger reckoned it must be incorrect because it implied something self-contradictory - the cat was alive and dead. It's a reductio ad absurdum.
I like how stuff like this is posted on Google+ while on Facebook I get flooded by month old memes.
Since the cat itself is an observer of whether or not there has been an explosion, its waveform is always collapsed to a state of alive or dead, regardless of whether or not we look into the bunker from outside.
my cat watched this with me. he thinks he wants to try this experiment with a dog
There is no rational basis on which to posit the state in which the cat is either alive or dead proposition in the first place.
To show the logical impossibility of this premise being true, imagine the following recursion: inside the bunker with the cat and the gunpowder, there is another bunker with a mouse and some gunpowder, and the cat, if it survives the explosion, will in time be able to open the bunker containing the mouse and observe whether it is alive or not; precisely what propositions about the mouse's physical state are true at any given moment?
Hmmm. Never thought of.this before, but is this just not man placing himself first in the order of reality. We have a tendency to do that, thinking we are the center of the universe. I mean what about kitty ? What about what SHE see's and what is affected by HER observations? Hmm..
This entire schtick was a dismissive joke by Shroedinger, told to demean the person he was talking to. Don't take it too seriously.
this is probably one of the least understood (or most misunderstood) thought experiments of all time. As Stephen Hawking said "When I hear of Schrödinger's cat I reach for my gun."
No cats harmed? Guess I'll watch anyways.
Very cool illustration of the idea. How about an alternate explanation that serves no real purpose to our experience but is interesting to ponder. Time does not exist, there is only one single moment, and our own perception of movement through time is merely an illusion. This still does not exclude alternate reality.
+A Wilson and yet it has been put to practical use in Quantum cryptography. Who'd have thought eh?
If a tree falls on a the cat in a hat, in a box, in a clearing, in a forest, and Pavlov's dog isn't around to hear it, does it drool?
If Pavlov's dog watches a film of it in Plato's cave, does it make for good TV?
I love minute physics on youtube. Give me a bloke doing a drawing and I understand far more than pure text. Schrodingers cat is an intellectually stimulating discussion. It is more about the science and philosophy of experiments rather than furtherance of our working lives. But it is one of my favourites too.
Until yesterday I didn't know about this "experiment", but then I've seen The Big Bang Theory series 1 part 17 :-)
i dont, plz send imformation
certainly no cats were harm, but u enjoyed the pleasure by grabing the moon in your palms.
Uhhh... I think I'll leave this one to the scientists!
Yeah, I think the minute physics are cute. And at least they could make people curious about the subject matter, even if they're somewhat inaccurate.
i cant play it, i see a kat eating burger? what does it mean plz?
I has answer: It doesn't matter. I still go about my life without knowing if reality can collapse into a single truth and you do the same. Same answer for how the universe came to be.
Veronica, I am quite impressed with the video it is one of the best explanations for this concept I have seen. It even included the historical significance. Thanks for sharing it with us.
BTW There are no unobserved events. Every event has an effect on the worldline of all its neighboring events forming the framework of reality. All events are thus "observed" by nearby casually dependent events. For instance, in the bunker example, the explosion sends minute ripples through the ground changing the soil so that when you walk towards the bunker your path is slightly different. The lag between the choice being made and you observing it does not really exist. In other words, our ignorance of quantum mechanical choices does not a universe create. Sorry Dr Bohr.
it means the kat is ususally this one is more of an exsperiment of blowin up poor kitty kat
This experiment will fail if they use basement/ceiling cats because as everyone knows they are immortal. So when you open the bunker they will still be alive and very very pissed off and the probability of 50/50 death or alive will shift to you.
Kitty is both alive and dead!
Leave the box closed for 12 month and the answer is easy
Why isn't the cat dead or alive; we just don't know it yet? Why does the cat have to be in suspended reality?
Sorry, I've love to look at it, but Im getting really tired of everything on YouTube being preceded by a 15-to-30-second ad.
Since we can't prove whether it is our observation that forces nature's decision or not because to do so would require observation then it's probably OK in a practical sense to say the cat has a 50/50 chance and leave it at that. Fun to think about though.
I like that people enjoy this thought experiment so much... seeing as it was meant as a joke... The experiment is ruined because the cat is living and is itself an observer.... Fun Fact: Schrödinger's cat is a LOL cat!
As a "curiosity killed the cat joke" I got it. As observation changing outcome, I went into a blank stare. I think I may have had some sort of epileptic incident. When I came to I remembered hearing something about this sort of thing on a quantum level and I went searching on the web and found this. My unlearned brain needs this simplified visual to even begin to understand the theory. Applying this theory to our everyday reality is truly a thought experiment. I think I need to go lay down.
before reading the comments. i new there where only 2 options. I was right!! No cat left any comments. I killed them all.
^this man was raped by al Stewart
+Christopher Himes The fact that the cat is living is actually irrelevant. To observe something in quantum physics is really to create an interaction that differentiates between that thing being in one state vs. another. For instance, to observe a particle's position, you create a detector that is located in specific region of space and which will register a signal if and only if the particle is in the same position. If you place many of these detectors everywhere and look to see which one registers a signal, you've now taken a measurement of the particles position. Even though the particle may not have had an exact position beforehand, this measurement gives it one. From that moment forward in time, any experiments involving that particle will behave as though the particle originated from this measured position and not from any of the other hypothetical places the particle might have been prior to the measurement.
+Tyler Brown - If it makes you feel any better, that's an utterly wrong interpretation of this thought experiment and leads to stupid theories that utterly misrepresent the rather mundane and mathematical quantum mechanics. +Tony Veroeven - Same to you... a cat would be clearly alive or dead, as it is not a particle subject to quantum effects. There is no wave function for a cat that exists in a closed system that can collapse when interacted with. (There's a key bit missing compared to the original that somebody points out above, but the focus is never supposed to be on the cat anyway).

The whole point is to show how -- at very specific sizes -- things behave oddly (and affect larger things). It's silly that a cat could be both alive and dead given these circumstances. But at a certain level (well smaller than a cat), it happens all the time. The "observer" is not a human - it's simply anything that takes information away from the system. Basically, if it interacts with any other particle (in a particular way), it is considered observed. Way less mystical or human-centric than it sounds.

It's pretty mundane and mathematical. My wife just walked out the door to go spend all day reworking a simulation that takes quantum effects into account. Her grad student and some of her post-doc work was specifically to do modeling of quantum effects (she did Proton Coupled Electron Transfer, which is, simplistically, when a proton and electron "jump" together).

+Carl Grahn - You say these theories don't help anybody? She's a theoretical chemist and works in the pharmaceutical research side of a research university to help model protein interaction. It's hard to say that actually healing and saving people's lives is of no "lasting benefit".

Thanks to +Andrew Piscitello for making some of the same points up top. This is a commonly misrepresented part of science.
Hey! I'm stuck watching these minutephysics ... can't get out :(
Lmao, showed this to R P Mcmurphy (my Cat). Sz he sees no humor in this.
I am not a physicist, but this seems like a bunch of BS to me. This seems a lot like the old question about a tree falling in a forest.

I suppose it follows a logical thought progression from a humanist standpoint, but I don't buy it.
Maybe it is to do with the interaction with the environment, i.e. if some detector interacts with the superimposed particle then it will have to assume a single quantum state rather then indeterminacy - so in the case of the cat and the radioactive poison, you would either get a cat that is dead or one that is alive because it must interact with the environment.

Also, in the cat experiment there is a mixing between classical and quantum physics, which doesn't always works - that's why we don't have a 'theory of everything' or quantum gravity because in their own domains the theories work (QM in the very small, and Classical Mechanics in the relatively large) but together they don't - hinting there is something more wonderful that we have yet to discover about the life, the universe and everything...oh and it's not 42!
On the other hand, theoretical physics has a rich history of positing "thought experiments" that makes the field very accessible to a novice like me. I enjoy exploring these thought experiments.
+Tate West You are thinking in the macro. This was metaphor was made as a way to try and comprehend what they saw actually happening when studying quantum mechanics. Schrodinger actually came out with this in response to the double slit experiment.

In the double slit experiment they did not observe the experiment and found the results to be baffling so they repeated the experiment whilst watching it and saw the results they originally expected and not what the results were in the first attempt. The only that changed was the act of observing the experiment.
The answer to the cat in the box....value vs purpose. We all are faced with these choices in life daily. Those who chose Value over Purpose run the chance of forestalling their God given senses; as such, they often bring harm to themselves and others. Individuals or (cats) who chose Purpose over value make more pragmatic choices; therefore, pay greater attention to their God given senses, and move and act in their best interest. As for the box....I say why imprison innocent life, science without Wisdom is a empty bag.
+Mike Mixon Could it be that each time this experiment is done it will have a different result no matter what? I read on Cracked that uranium molecules do not decompose if you are looking at them under a microscope. You might want to investigate that >*sparkles*< I'm wondering who put what in their food and if they'll share.
+David Greenberg and here I thought whether or not the cat was dead was the whole point of the experiment. At least as described. My point however is that the experiment is nonsensical. Describing quantum mechanics specifically in response to my criticism of a metaphor about quantum mechanics really doesn't damage my argument.
I know vastly superior minds than mine back this one, and it may work for quantum particles, but in the real world, with cats & such, it never made sense.

Yesterday was Valentine's Day and I walked into the house with my hands behind my back. My wife didn't know if I had (A) a Valentine gift in my hands or (B) no gift in my hand. It was not, however, true that I had both A & B (gift & no gift) in my hands and when my hands revealed (B) no gift, it was not my wife's observation that caused that state. It was B the whole time but simply not observed.

Kind of like the Zeno arrow thing. Theoretically the arrow can't move...but of course it does, and therefore killed lots of people in various early wars.
+Tom Sullivan - But in the alternate universe that was developed before the wave function was resolved, you did have the gift behind your back.
The Xeno thing doesnt say the arrow is stationary, just that the man pursuing can only run a certain speed and therefore can never catch up.

So hard did the wife slap you? :-)
who are you? you randomly showed up on my feed.
this is a whats hot on google+ post... if you dont want to see them turn down the slider on it
JC - It's a hot (ie popular) post - we can all see them by default.
I think everyone was stoned when they thought this up in the first place.
To all the doubters, well, this is just the world we live with. In practice its impossible to do it to a cat, but its completely possible in principle. People have rightly claimed that Schrodinger's point to devising this thought experiment was to show that the idea was absurd. But that was before Bell's theorem in 1964, which was the last nail in the coffin for attempts to explain QM in a way that is intuitively pleasing. Its just unreasonable to deny that this is the way the world works after 100 or so years of experiments conclusively demonstrating it, and many proofs showing that attempts to classicalize quantum behavior are unworkable, requiring retrocausality and other absurdities.

Of course we do have a better idea about the resolution of some of these things today. There is no fundamental role for consciousness, but because humans are quantum mechanical beings too, not just the systems under study, we become entangled with the systems we analyze. (this isn't strictly agreed upon, and you can never discern properties of your own superposition, but it is something that allows QM to make sense without a role for consciousness) Macroscopic creatures like cats cannot be maintained in coherence because they need an atmosphere to breath, and every atom bouncing off of them exchanges quantum information. But again, that is a practical difficulty only, all the rules of QM still apply to cats as much as electrons or anything else.
it would be funny if the burger ate the cat.
I think there are more important things to contemplate.
Your mere observing influences what happens...its not any more a thought experiment. It is proved at quantum physical level
+Veronica Belmont Check out TS Eliot's "The Naming of Cats" - He seemed to have been fond of this thought experiment as well. His answer is the obvious one, once we shed a bit of speciest hubris, The Cat Himself Knows.
Wow 4 me is amazing how many people invest their time to comment, ij just 12 hours, whatever happens in their heads hahaha. Well done Veronica. And about the cat... i love burguers to hahaha
Lol@ Schrodinger's wombat!!

I can just hear Schrodinger and Einstein arguing over this.

"You zee Albehrt, zeh wahmbaht ees bos alive ahn zee wahmbaht ees dett..."

"Zchrodinger zou ah zuch a poopstick! Gott dahz naht play mahmosetz unt wahbahts vit zee uneeverz!"
It's never been a good question. It's absurd. I'm a pretty smart guy. I get what they're getting at.....but it's reason beyond reality. Whether we ever open the box/door/etc. or not, whatever has happened has happened. We do not, as the video suggests, cause the outcome by looking at the cat. It's putting thoughts of what could be above the reality of what is. Junk physics. nothing more.
Cool, and johnathan raven how do you know
Ahh Duality! Photon / Wave? Alive / Dead? Caf / Decaf? Blues / Jazz? The Universe does play dice. Sorry Einstein.
Great presentation! I love the simple marker approach.
I see people keep referring to the tree in a forest situation.... I do wish people would use a bit more logic when thinking of that particular puzzle. The problem there seems to be that people have forgotten what sound actually is. The answer is stunningly simple - IF there is no-one in the forest (and more importantly there is also no other form of life with the ability to convert air movements into electrical impulses) then NO the tree does not make a sound as it falls - it does however still move the air. There now - that was much easier wasn't it. Now - all you need to do to make it easier is think of what happens if an explosion happens in space (if there is no air - there is no sound) - sorted.
That is my all time favorite! I often find myself using that while playing games "Is there an enemy around this corner??" I prefer to be prepared for the answer being yes. Sadly, that doesn't stop them from killing me if there is. If you look at BF3, at a 64 man server, the possibilities are endless and so would be a branch with its own sub-branches.

[[Who/how many people bought the game in how many parallels]] [[Who is playing in one and not the other and a set time]] [[Who sees something a second earlier in one parallel and not the other thus bringing the team to a victory instead of a loss]]

My mind is always on thoughts like this but not necessarily gaming related...
pics on accidenI got these pics on here accidently and now I can't get them off. Just ignore them till I can figure this out!!
I would like to add variables. Perhaps we add an endless supply of food and a computer to the bunker and then never look inside. maybe the bomb never blows and the cat lives his life out happy watching videos like this over and over laughing his ass off.
Things happen without being observed.
I agree. Aside from the very small,where the photons we need to observe something will affect it, things will happen whether we oberve them or not. It's pretty arogant to think we affect everything we see.
Our interests in relativity are selfishly motivated... Ba dum, dum...
It's obvious. The universe decides and knows if the cat is alive or dead. It just doesn't let anyone else know until we check.
Well, if the universe doesn't let us know, then we observe that the cat is neither alive nor dead until we open the damn box, because we don't observe it being alive or being dead until we do open the box.
Veronica Belmont, can you please stop having such cute bangs? I'm trying to grow mine out! Thanks.
I don't know if the first time I heard of this was on The Big Bang Theory or if that was just the first time it stuck... either way doesn't look good for me!

Great video!
cute bangs????????????????????????????
There is a probability that the cat will die on it own accord, that has nothing to do with checking to see or the powder blowing up.

The thought experiment makes assumptions without taking in consideration of all the possible variables.
I agree with +Stefen Randall. Take the part where cat is inside with the unstable gun powder. The cat could NOT see the gun powder blow up and it still blow up, seeing how the "container" the two are inclosed in, might, and probably is, air-tight. The cat would have know physical visibility of the gun powder blowing up.
schrodinger's cat is stupid. something doesn't make the decision of being dead or alive as soon as we see it.
Hey guys do you want to do the picture contest named:
I have herad about this- this is the first time someone has actually explained it to me :P
Wow! This is confusing... Haha so if I never look at the cat, it will never die...
But them it wouldn't be alive either! 
arjay u
minutephysics FTW
Awesome! I've just recently stumbled upon this experiment and it's a total mind trip. Thanks for sharing. :)
Ya decia q faltaba alguien q hiciera una pregunta como la de leonel .. •_•
Minute Physics is awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Schrödinger's cat was a thought experiment created by Erwin Schrödinger. It was his attempt to point out how ridiculous quantum mechanics was. He was attempting to mock the idea of superposition by using a macro sized experiment.

However quantum level events cannot be scaled up beyond the sub-atomic level. Schrödinger was wrong; superposition is very real. We cannot know the state of sub-atomic particles such as electrons until we measure them. Until then they exist in all possible states. By measuring them we cause them collapse into a single state.
Sad no one has pointed out yet that the experiment must be triggered by a quantum event (subjected to quantum uncertainty) affecting macroscopic events, otherwise there's no superposition of living/dead cat. A barrel of explosives would not produce that.
+Daniel Drehmer There doesn’t need to be a quantum event in the Schrödinger's cat experiment. The cat represents subatomic particles in that we don’t know their position until we measure them. Until we do the particles exist in all possible states.

So until we know whether the cat is alive or dead it is both; that is the superposition. By opening the door and observing we cause the superposition to collapse into one of the two possibilities i.e. either a dead cat or a living cat.
+Daniel Drehmer multiple people have pointed that out :) and +kevin Johnson yes, there does need to be a quantum event linked to the cat for the experiment to make sense. In the macroscopic world we normally live in, there are no superpositions. Without that part of the experiment, the cat is either alive or dead, and we just don't know yet.
C Oh
I really like that explanatory video and the drawings in it. I couldn't resist getting this very amusing Schrodingers Cat t-shirt, which plays on the current fad for zombies, with the cat both dead and alive, my favourite of all the Schrodingers Cat t-shirts around +Veronica Belmont
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