It's still a very famous experiment and in fact far more people have heard about
Schrodinger's cat than have any idea who is Schrodinger or what the cat was doing?
Schrodinger's cat is what physicists call a
Thought experiment. What's called a Gedanken thought experiment from the German thought [one]
I know this is an experiment that you'd like to do and you can talk about the consequences
But could you never do in practice like what would happen to the earth when it was going round around if the sun disappeared?
You could never make the sun disappear, but you could still calculate what would happen to the Earth
Schrodinger was an Austrian physicist who?
when the
Nazis invaded Austria
Fled to the uk and then to Dublin waking [add] quite a colorful career and actually fathered an illegitimate child
But that's nothing to do with his cat in the cat experiment was something he proposed
to try and explain an
Idea or how stupid he thought one of the ideas [that] had been proposed by quantum physicists working in?
Copenhagen who were discussing how if you couldn't observe something which had two possible [states]?
The two states could be muddled together, so you couldn't tell which was [which]
Schrodinger's cat is a thought experiment in which a cat is put in a box
Showing his cat thought experiment. Well it goes something like this imagine you have a cat. I'm sorry
this is not a very good model, but you can [imagine] this is a cat which can either be alive or Dead and
His idea was [that] you have a steel box which can be closed so that the hole it can be cut off completely?
From the outside and nobody not even physicists can see inside
[so] [the] idea is that you put the cat in the box
and
at the same time you put inside a small vessel that contains a tiny amount of a
radioactive [material] and
The radioactive material has a few atoms
And you choose the number of atoms so that during a period of say an hour
There's a 50% chance that one of them might decay
Radioactively and give out a particle
So you put that in the box?
So now [you] have the cat the radioactive material you then take a geiger counter
Here we have a very fine geiger counter which can detect
whether the radioactive Decay has taken place or not and
then and this is the cunning part
You connect the guide counter to hammer
which if it detects something it will break a
small glass container containing cyanide
which is poisonous which will come out and kill the cat so we now close the Lid and
we start
[timeing]
So we know that
While the box is closed
inside
During the period of one hour there's a chance that a radioactive decay might take place. We there's no way of us predicting
There are only equations. We write down how much physics
We try to do that is a quantum process, and we simply can't predict it and if it takes place the geiger counter
Triggers
gets the hammer the hammer smashes the cyanide and the cat dies the key question that
Schrodinger asked or the key Gedanken experiment that he put forward is well think about. What is the state of the cat?
Before you open the box since we don't know whether the radioactive decay has taken place or not
under this idea proposed by the people in Copenhagen the cat
Doesn't know whether it is Dead or alive
You've got no way of knowing whether the cat in the box is alive or Dead
Quantum mechanically what you would see is that the cat is in a superposition?
Of states, it's both alive and dead, and it's only when the our app is [up] and we open the [door]
That we then
Determine whether the cat is dead or alive, but while the door is shut
The cat is in this mixture of Dead and alive state
Now the point of this experiment at least as far as I know as a chemist was that trading has said
This is a crazy idea you can't have a cat that is Dead or alive
Now Shirley's idea was to bring this strange
Quantum business
to bring it patch to the general public
But [also] to make it the thing more real and relevant the genius of this experiment
And why people have thought about it so long and still get excited is
Because it links and at an event on the atomic scale one atom
Disintegrating or not to something that everybody can understand the cat being dead
or alive
So you can't tell the cat's dead or it's alive
I mean clearly the cat is never half dead and half alive is either alive and Dead, and I think the usefulness of the
Of a showing us cat story is a caution
it's really a cautionary tale that we have to use different rules of
thinking when we're dealing with everyday objects like cats and
Quantum objects, so schrodinger came up with this actually to try and show the the Pitfalls with some
elements of
the Quantum mechanical
[concept] because it is such a very strange concept he wanted to try and show the
ludicrousness of thinking like this the idea that the cat is in two separate states at the same time it's both alive and Dead and
This was really that that's the copenhagen interpretation that you can have this superposition of States showing
I really wanted to show that that wasn't the case, and [that] was just ludicrous to think like that
But the problem is we've done experiments and at this quantum. Level. That's how matter behaves
Our everyday notions of things being a well-defined states
For large-scale objects just do not apply the quantum level and we have to use
Just other ways of thinking
And that's what quantum mechanics is I mean there are lots and lots of examples the one
Probably the most famous one is [the] electron has a spin it in some sense behaves like a little tiny spinning top
[but] it's a weird quantum mechanical kind of spin
So it has all sorts of strange properties
but you can think of an electron as a little spinning top and
So one of the classic sort of [superpose] states you can have is you can actually you know there are two ways that spin think
And spin right it can go Clockwise or anti-Clockwise
You can actually have an electron that hasn't yet made up its mind which state it's in
so it actually is in a superpose state where it's both rotating one way and rotating the other way at the same time and
it's only when you do an experiment to actually measure the properties of that electron that it collapses into one state or the other so
It spins clockwise or anti-clockwise, and so that's an example of a quantum [mechanical] object
Which is can fundamentally be in two states at the same time?
Einstein got very excited about this and
wrote two Schrodinger later
Except that in Einstein's case he imagined it with explosives rather than cyanide
Which perhaps might be more dramatic?
but is no good because if the explosive went off it would destroy the box, so it would spoil the idea of the
Experiments. I thought answer I was clever. That's a stupid idea
Well perhaps he had the Strongbox