Quantum mechanics
Quantum mechanics blows my mind.
No matter how many times someone patiently explains (usually with the help of ping-pong balls) that it is possible for atom-sized objects to exist in two places at the same time, or to be both a particle and wave at the same time, I end up saying, “Wha… Bu…?” and looking gormless. Inside my head, my inner Scotty1 yells into an intercom “The engines cannae take it, Cap’n! The dilithium crystals are gonnae blow!”, while being showered with sparks from an overloading console. I think of myself as a relatively intelligent person, and I do a fair bit of thinking about abstract things most days, but I can’t seem to get a mental hold on a theory that involves completely non-intuitive ideas that blow raspberries in the face of common sense. I do enjoy it though; it’s the intellectual equivalent of riding on a really intense rollercoaster — very scary, but rather exhilarating.
So I could sympathise completely with the look of terrified bewilderment on E’s face as various physics professors tried to help him understand quantum mechanics in the documentary Parallel Worlds, Parallel Lives. E (Mark Everett of the band Eels) was trying to find out about his father Hugh Everett III, who was the originator of the idea of parallel worlds (the ‘many-worlds interpretation’). Hugh died when E was quite young, and it sounds like he didn’t communicate much with his children when he was alive. E lost all of his immediate family within a relatively short space of time, so it’s understandable that he has — until now — found it quite painful to think about. It was a wonderful documentary, both from the perspective of the science, and the personal journey E went on. After talking to friends and colleagues of his father, he ended up feeling like he knew Hugh a bit better, and seemed to be more at peace with his past.
One of the bits I enjoyed most was when E was listening to some dictaphone tapes his father recorded, which he had never heard before. He wasn’t even sure that he would recognise Hugh’s voice, because he died so many years ago, and spoke so seldom in the home. In the end, he did recognise his voice, and was amazed to hear him sounding so talkative and enthusiastic, while chatting with a colleague. E had already said that his father was quite tolerant of his adolescent drum practices, and sure enough, half way through the tape, a loud drum solo comes in the background, and we know exactly who is responsible.
1 What? You mean you don’t have an irascible Scottish Starfleet engineer in your brain? Just me then… ↑
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I have often heard it said that a determined high school student can understand relativity, but that nobody has ever understood quantum mechanics.
by Milan @ 29/11/2007 8:35 pm • Permalink •
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It seems to me that the problem most people have with the idea of quantum theory boils down to all the years in education we learn that life becomes more exact and definable. As a youngster, we learn milk is good for you, and then as we grow older, we learn about chemistry and why milk is good for you (calcium). The same happens with matter. At a very young age, something exists only because we notice it, then we learn about "permanence," and then we learn about atoms and molecular interactions and attractions, etc.
I think very young children, who have not had logic melded into their core of thinking like adults, would have a better chance at believing the theory because they haven't learned everything adults take for granted as "intuitive."
by David @ 30/11/2007 2:03 pm • Permalink •
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The trouble with quantum mechanics is that the spanners are so small.
Anyway, Einstein misunderstood his own theory, the key point was time, not the speed of light. Time varies. The older you get the faster time moves, and it moves exponentially. See..... it's nearly Christmas again!
by Jonathan Briggs @ 30/11/2007 6:24 pm • Permalink •
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Milan: One of the physics professors in the documentary said much the same thing.
David: Interesting idea, but I'm not so sure that young children wouldn't have similar difficulties to adults with the theories. Quantum mechanics violates some very fundamental and deep seated theories (like two objects not being able to occupy the same point in space and time) which we know from experiments that even young babies possess. I don't think those theories are things that we learn, and I think that's why it's so intellectually troubling. Certainly, young children might be more prepared to just say, "It's magic, then", and be content with that explanation. But I could be completely wrong - we should do an experiment! Does anyone have any cooperative children they could explain quantum mechanics to?
Jonathan Briggs: :-D I know that feeling well...
by bsag @ 01/12/2007 4:32 pm • Permalink •
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Two Particles cannot be in two places at the same time, our Macroscopic world is the AVERAGE of the real world. Waves on the shore for example bear no resemblance to Atoms, yet they are made up of atoms.
There is a fundamental Law of Nature called the Heisenberg Uncertainty Principle, which is that 'you' can never know the precise location and momentum of a particle more than a certain amount of precision.
Now this law is ABSOLUTELY FUNDAMENTAL To Nature itself, it has nothing to do with the measuring accuracy of our equipment or of its design, it is inherrant in nature itself.
It explains for example atomic structure.
The Nucleus, being more massive, (heavier) has a slower momentum so it's position is easier to define, though not absolutely remember,
Electrons, being negatively charged are attracted to the Positive Nucleus, however their small mass means their Momentum HAS TO BE GREATER so they are to be found in a Large Volume around the Nucleus, because remember, the precision of the accuracy of their location has to be less.
Electrons 'travel' in orbits. around the Nucleus BUT, the Heisenberg Princinple still applies, so they do NOT follow a path around the Nucleus.
They exist within Orbitals about the Nucleus BUT they have no definate location, they are more accurately considered to have a statistical probability of being found at a precise location. but can NEVER be found at a PRECISE location because that would violate the Uncertainty Principle, the product of the definable location and the Momentum of a particle cannot be known with accuracy greater than a specific amount.
DxDp > h/2.......The precision with which 'you' can Know the location and momentum of a Particle is Always greater than h/2.
Note, this has nothing to do with the accuracy of our equipment. It means for example that when two electrons interact, there is a degree of 'fuzzyness' about the position of the interactions because even the electron cannot 'feel' the position of the other electron with absolute certainty.
So, the structure of an atom is the way it is because the Nucleus, being more Massive (Heavier) there is less uncertainty about its position. The electron, being much lighter has a greater uncertainty in its position.
A better way then of looking at the structure of an atom is to imagine the Nucleus as a Tiny Fuzzy ball, with no definate location, Surrounded by an electron cloud, this 'cloud' being where the electron has higher probability of existing, but remember you can not look closer and closer to see its exact position. Look from afar at an electron, it appears as a dot, but the closer you look at it, the fuzzier it gets.
Energy causes atoms to move, vibrate, what then would happen if we cooled some helium or oxygen to Absolute Zero (Yes there is an absolute Zero of Temperature, an object cannot be coolled to less than Minus 273 degrees C which is Absolute Zero, or Zero Degrees Kelvin.
Now what happens if we cool matter down to Absolute Zero, according to the above since we cannot know both the Position and Momentun to an infinite precision then even at Absolute Zero, there should still be some Uncertainty in these values. Lo and Behold, when this experiment is done, we find that the Atoms are not Frozen Solid and motionless because remember, the Heisenberg Uncertainty Principle ALWAYS applies and we can never know the Precise location to an accuracy greater than h/2.
We do not notice this curious effect in our everyday life because h/2 is such a tiny tiny tiny value.
The Heisenberg Uncertainty Principle is one of the reasons why Quantum Mechanics causes Problems of Understanding to Students.
because we live in the Large world, we expect atoms and electrons to behave similarly, they do not, electrons are NOT ball bearings travelling round a bigger ball bearing in the center.
It's probably best to be a little humble and accept the Universe was Not designed with our preferences in mind.
Nature is the Way she is.
Personally I love the fact that Nature is so exquisitely interesting and will challenge our understanding more as we explore deeper and deeper.
by British Patriot @ 04/12/2007 7:07 pm • Permalink •
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Dear Sir / Madam I am writing to inform you of a New Defence and Security Organisation, The UK National Defence Association recently established in the Uk and headed by Senior Members of the Armed Forces, the aim of said Organisation is to Lobby for Better funding for our Armed Services so that they may better be able to Protect this country and Its People. Would you be willing to Link to this Organisations website (details Below) and would you be willing to forward the Link on to any / all of your contacts. Membership is Open to ALL Uk Citizens, concerned about matters of security. Thank you Founding Paper. http://www.uknda.org/mydocuments/myfiles/NDA-FOUNDING-PAPER.pdf UKNDA Chairmans Column http://www.uknda.org/chairmans_column/c-12.html Home Page http://www.uknda.org/
Also, can you support this worthy cause, send a Pressie to our Boys in the Gulf.
http://iaindale.blogspot.com/2007/12/send-parcel-to-our-boysgirls-in-itaq.html#links
by British Patriot @ 04/12/2007 7:11 pm • Permalink •
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This uncertainty/fuzziness sounds like the W bit of Boltzmann´s S=k log W. Nobody believed him and he topped himself. I must admit that not having your lifetime research accepted by your peers must P / U = off somewhat.
You are right about time & age though. When I was faced with a decision at the age of 24 of whether to commit myself to military service to the age of either 38 or 55, I could not imagine being 38 ever, & 55 was like trying to imagine what it would be like on the outside of the universe looking in. Now at the age of 77, it is a mere instant....with a certain amount of Mr H´s uncertainty!
by JakP @ 05/02/2008 1:02 pm • Permalink •
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In many ways QM is not waired at all. It is simply a formulation of the fact that the matter is stabie and ordered when tied together with forces and shows an arbitrarynes when this is not so. Classical physics did not have any formulation for this. But QM does not give any deeper explanations. Therefore there is nothing to understand beyond this. It is not worth pondering on a theory that do not give any information beyonf the probability of observations.
QM simply do not say that a particle is at two places simultanouly. It do not tell anyying at all about this. What it however says is that a particle may have a chance of being observed om several places.
by Knut Holt @ 21/06/2008 8:25 pm • Permalink •
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