Quizzes & Puzzles0 min ago
Heisengberg's Uncertainty Principle
Can anyone explain in a relatively simple manner, that non-scientific people would understand, exactly what Heisenberg's uncertainty principle is ?
A simple example of how it might be used would also be welcome.
A simple example of how it might be used would also be welcome.
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If you do the maths/physics you find there are certain pairs of values you can not not exactly no matter what you do. It's not a measurement deficiency it's to do with the equation showing the more accurate one iis the less accurate you are on the other.
One of the consequences of this is that certain things :-) will always be uncertain. Leading to things that common sense tells you can't occur, occurring.
Basically what it says on the tin; some things are uncertain.
One of the consequences of this is that certain things :-) will always be uncertain. Leading to things that common sense tells you can't occur, occurring.
Basically what it says on the tin; some things are uncertain.
I said, "If you do the maths/physics you find there are certain pairs of values you can not know exactly, no matter what you do. It's not a measurement deficiency it's to do with the equation showing the more accurate one iis the less accurate you are on the other.
One of the consequences of this is that certain things :-) will always be uncertain. Leading to things that common sense tells you can't occur, occurring.
Basically what it says on the tin; some things are uncertain.
Oh sorry, an example. Quantum tunneling where a particle crosses through a classically-forbidden potential energy barrier.
Possibly the Big Bang might be a bigger example. Something for nothing - the ultimate free lunch."
One of the consequences of this is that certain things :-) will always be uncertain. Leading to things that common sense tells you can't occur, occurring.
Basically what it says on the tin; some things are uncertain.
Oh sorry, an example. Quantum tunneling where a particle crosses through a classically-forbidden potential energy barrier.
Possibly the Big Bang might be a bigger example. Something for nothing - the ultimate free lunch."
Yes and No
I can explain what it is fairly simply but the derivation is rather complex and you'll have to take a not on trust.
There are certain pairs of quantities such as energy and time or position and momentum and there is a limit to how accurately both can be known at the same time.
*This is not a practical limit due to our ability but a fundamental piece of how the Universe acts*
So you can know exactly where an electron is but have no idea of it's momentum or vice versa or you can have a rough idea of both.
This leads up to the joke about the physicist stoped by the speed cop who says:
"Do you know how fats you were going?"
the physicist sys:
"No but I know exactly where I was!"
(I'll get me lab coat)
I can explain what it is fairly simply but the derivation is rather complex and you'll have to take a not on trust.
There are certain pairs of quantities such as energy and time or position and momentum and there is a limit to how accurately both can be known at the same time.
*This is not a practical limit due to our ability but a fundamental piece of how the Universe acts*
So you can know exactly where an electron is but have no idea of it's momentum or vice versa or you can have a rough idea of both.
This leads up to the joke about the physicist stoped by the speed cop who says:
"Do you know how fats you were going?"
the physicist sys:
"No but I know exactly where I was!"
(I'll get me lab coat)
OG is like my brozzer - when you ask him to explain more,
he just shouts it louder ... until it sounds like a road drill and the neighbours get the benefit of the opinion
Heisenberg first thought of this in the tram when he realised that if you watched a politicians lips you could never be certain he was telling the truth
another example is buttered toast - it never ALWAYS falls btter side down
a third.... if you go to an RBS ATM - it will always pay the directors a bonus but need not necessarily give you your money - or even admit your are in credit.
Did you know you can now do nonmathematical A level physics ?
a fourth one - thanks to Kurt Godel - it is uncertain that it always applies.....
he just shouts it louder ... until it sounds like a road drill and the neighbours get the benefit of the opinion
Heisenberg first thought of this in the tram when he realised that if you watched a politicians lips you could never be certain he was telling the truth
another example is buttered toast - it never ALWAYS falls btter side down
a third.... if you go to an RBS ATM - it will always pay the directors a bonus but need not necessarily give you your money - or even admit your are in credit.
Did you know you can now do nonmathematical A level physics ?
a fourth one - thanks to Kurt Godel - it is uncertain that it always applies.....
Thanks everybody. I have done some research on Wiki since my original post, and I THINK I understand matters a little better !
Wished I has studied for my O Level Physics rather better than I did, back in 1969...I am sure there are lots of others things that I need to understand better than I do at present. I actually passed it OK but it all seems to be a tad vague now. Radical ideas don't seem to penetrate the old noggin at 60 nearly as well as they did when I was 16.
The uncertainty must make accurate calculations terribly difficult though.
Wished I has studied for my O Level Physics rather better than I did, back in 1969...I am sure there are lots of others things that I need to understand better than I do at present. I actually passed it OK but it all seems to be a tad vague now. Radical ideas don't seem to penetrate the old noggin at 60 nearly as well as they did when I was 16.
The uncertainty must make accurate calculations terribly difficult though.
Not at all - accurate calculations of certain things remain entirely possible -- indeed the most accurate measurement yet is of something called the electron's "Magnetic moment" - which is known to about 10 or more decimal places. Along the line you have to be aware of the Uncertainty principle in measuring this but the limit in accuracy it imposes isn't all that bad.
Surely the main point about HUP is that at the atomic level you cannot observe what is going on without interfering with what you are observing.
Since a quantum of light is the minimum amount of energy you can have, whenever you observe things at this level, you must add at least the amount of energy contained in a quantum of light to the system you are observing and therefore you make certain observations uncertain.
Since a quantum of light is the minimum amount of energy you can have, whenever you observe things at this level, you must add at least the amount of energy contained in a quantum of light to the system you are observing and therefore you make certain observations uncertain.
OG's post captures the truth more than yours does, vascop, I think. This is a statement that is independent of how you conduct the experiment or who is measuring and is a property of the qunatum systemn itself. While the light analogy is useful the HUP is about more than just limits of experimental accuracy.
Well, let's face it. 'Uncertainty Principle' is an oxymoron.
Seems that the more we learn about the nature of the universe we live in - the less certain we become of our own existence within it. To view reality objectively we must first eliminate ourselves as observers and ask how it would look if we weren't there.
Seems that the more we learn about the nature of the universe we live in - the less certain we become of our own existence within it. To view reality objectively we must first eliminate ourselves as observers and ask how it would look if we weren't there.
vascop //
Surely the main point about HUP is that at the atomic level you cannot observe what is going on without interfering with what you are observing. //
No that is not what it is about at all. It is a fundamental consequence of the fuzzy nature of the universe
// Since a quantum of light is the minimum amount of energy you can have, whenever you observe things at this level, you must add at least the amount of energy contained in a quantum of light to the system you are observing and therefore you make certain observations uncertain.//
There are ways to observe without adding any energy.
My favourite is a variation on the double slit experiment. It is possible to create a special filter where the probability of a photon taking a designated branch of the system can be controlled.
Even when only one photon passes through and is known to pass down the designated path the availability of the other path can be determined by the trajectory of the photon.
If it passes straight through the slot then the other slot is known to be blocked. If it is diverted then the other slot must have been open.
Hence it is possible to determine the state of the hidden slot even though no photons passed that way and hence no energy was added to the observation.
Surely the main point about HUP is that at the atomic level you cannot observe what is going on without interfering with what you are observing. //
No that is not what it is about at all. It is a fundamental consequence of the fuzzy nature of the universe
// Since a quantum of light is the minimum amount of energy you can have, whenever you observe things at this level, you must add at least the amount of energy contained in a quantum of light to the system you are observing and therefore you make certain observations uncertain.//
There are ways to observe without adding any energy.
My favourite is a variation on the double slit experiment. It is possible to create a special filter where the probability of a photon taking a designated branch of the system can be controlled.
Even when only one photon passes through and is known to pass down the designated path the availability of the other path can be determined by the trajectory of the photon.
If it passes straight through the slot then the other slot is known to be blocked. If it is diverted then the other slot must have been open.
Hence it is possible to determine the state of the hidden slot even though no photons passed that way and hence no energy was added to the observation.
I think beso is talking about a variation where the second slit can be blocked or open when the choice is made randomly by a computer or something like that. Then you can tell what choice the computer made without looking at the slit because the photon will behave differently depending on whether or not both slits were open.
There are several ways to vary the double-slit experiment -- all of them clever, and all of them obeying the predictions of Quantum Mechanics.
There are several ways to vary the double-slit experiment -- all of them clever, and all of them obeying the predictions of Quantum Mechanics.
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