EPTBrief googling found me not much information.
Edit:
I more so want this to be about why we think things take up space? Photons do not take up any space but when it turns into mass it gains volume? Why?
Why do fundamental particles take up space?
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syth99
United States59 Posts
Brief googling found me not much information. Edit: I more so want this to be about why we think things take up space? Photons do not take up any space but when it turns into mass it gains volume? Why? | ||
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tryummm
774 Posts
Sound good? | ||
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syth99
United States59 Posts
On March 24 2012 10:56 tryummm wrote: Give me 2-3 more years of studying physics and I'll PM you an answer. Sound good? haha, sounds great | ||
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munchmunch
Canada789 Posts
On March 24 2012 10:54 syth99 wrote: Might be over my head on this one, but I think it's the Pauli exclusion principle, a fundamental law of quantum mechanics.I have been thinking about this a bit since i saw a tv show and someone stated the size of an electron. Why do fundamental particles take up space? if i was to take two electrons and push them together strong enough to overcome their repulsive forces what stops them from taking up the same space? Brief googling found me not much information. Edit: Oh ShadowWolf, how embarassing for you  | ||
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ShadowWolf
United States197 Posts
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N3rV[Green]
United States1935 Posts
2 things cannot occupy the same space if they are solid. This assumes electrons are solid. | ||
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sheaRZerg
United States613 Posts
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Lixler
United States265 Posts
On March 24 2012 11:21 N3rV[Green] wrote: Simple, an electron is a thing, with mass and size and charge. 2 things cannot occupy the same space if they are solid. This assumes electrons are solid. It's nigh-meaningless to call something on the particular level "solid." The actual forces that keep fermions apart have nothing to do with "solidity," which is really just an emergent property of electromagnetically interacting macroscopic bodies anyway. | ||
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dangthatsright
1160 Posts
The Heisenberg uncertainty principle tells us that the position and momentum of a particle cannot both be measured exactly at any one time (more precisely, the product of the errors is at least the reduced Planck's constant over 2). This basically tells us that you can only describe a particle's state with a probability distribution. For the electrons in an atom, this is what the electron orbitals are. The Pauli exclusion principle tells you that no identical fermions (for example, the electron) can have the same quantum states. Electrons in the atom have their quantum state described by four quantum numbers. Of these, the first three determine the electron orbital and the last one is the so-called spin of the electron. What this means is that essentially, two electrons can in fact be in the same place (though we are referring to the fact that they're in the same orbital) as long as they have different spins. | ||
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Chaves
Brazil315 Posts
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Candadar
2049 Posts
Also, Pauli Exclusion Principle. | ||
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turdburgler
England6749 Posts
On March 24 2012 11:21 N3rV[Green] wrote: Simple, an electron is a thing, with mass and size and charge. 2 things cannot occupy the same space if they are solid. This assumes electrons are solid. epic troll | ||
micronesia
United States24779 Posts
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Serpest
United States603 Posts
Complicated, I know, but then I just finished my QM final exam today. | ||
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Roe
Canada6002 Posts
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Candadar
2049 Posts
On March 24 2012 12:05 Roe wrote: how could something that exists not take up space? Because it's so incredibly small its atomic mass is essentially 0. With a quick search the estimated mass is like 9.10938188 × 10^-31, which again, is so small it may as well be 0. Add into that that they move at near the speed of light, Heisenberg Uncertainty Principle, and Pauli Exclusion Principle and well -- you can't mash together two Electrons as described in the OP. So yeah. Electrons exist but, for all intents and purposes, do not take up any space (technically). | ||
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d3_crescentia
United States4054 Posts
On March 24 2012 12:20 Candadar wrote: Because it's so incredibly small its atomic mass is essentially 0. ... are you equating mass and position/volume? | ||
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micronesia
United States24779 Posts
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Candadar
2049 Posts
On March 24 2012 12:28 micronesia wrote: I think he just means that for extremely small particles the everyday concept of position and volume aren't applicable. Technically they aren't for everyday objects either, but the approximation is so close that we neglect the difference. ^ But hell, I won't pretend like I know what the fuck is going on in the Quantum/Subatomic world.  | ||
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keeperton
United States233 Posts
On March 24 2012 12:04 Serpest wrote: Actually, electrons with the same spin can't occupy the same quantum state - a slight difference in semantics. Electrons have two spins: spin 1/2 (which is characteristically referred to as spin up) and spin -1/2 (spin down). Also, electrons (as do other quantum particles) don't actually occupy a particular location, but rather, they exist within a probability space. So when someone says two electrons occupy the same space, what they actually are saying is two electrons with degeneracy and opposite spins are within an area (of which their location comes down to energy probabilities). Complicated, I know, but then I just finished my QM final exam today. This is also true in writing the electron configuration of an atom. Doesn't necessarily need to be as complex as quantum mechanics in this case as that's more of a general chemistry thing. | ||
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DoubleReed
United States4130 Posts
They take up space because that's the way reality works. I suppose you could invent a reality where they don't take up space, but that's not the one we live in. What makes you say that photons do not take up any space? I'm pretty sure that's incorrect. | ||
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pedduck
Thailand468 Posts
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deathly rat
United Kingdom911 Posts
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dangthatsright
1160 Posts
In the context of the Pauli exclusion principle, photons are bosons and thus don't have to obey the Pauli exclusion principle. This allows many of them to occupy a single state. But how that translates into "taking up space" requires the phrase to be cleared up. | ||
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UniversalSnip
9871 Posts
On March 24 2012 11:53 micronesia wrote: Quantum states aside, I would think that the energy needed to get them that close would disintegrate them lol Can you disintegrate a fundamental particle? It's not like I actually know what any of this means, but particularly that makes me confused about the meaning of fundamental. What are you going to disintegrate it into? Doesn't 'fundamental' imply it doesn't have smaller pieces to break up and fly apart into? | ||
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vega12
Japan73 Posts
On March 24 2012 16:54 UniversalSnip wrote: Can you disintegrate a fundamental particle? What micronesia meant, I think, is that the two electrons would require such high energies to get that close, that the extra energy would start creating other particles through intermediate virtual photons. | ||
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adwodon
United Kingdom592 Posts
On March 24 2012 13:04 DoubleReed wrote: I believe the current understanding is everything is energy and waves. Particles are essentially dense clusters of energy. They take up space because that's the way reality works. I suppose you could invent a reality where they don't take up space, but that's not the one we live in. What makes you say that photons do not take up any space? I'm pretty sure that's incorrect. There is no current understand like this, all 'understanding' at this level of physics is just maths which is validated by numbers on a screen that the maths predicts, it tells us nothing about what actually happens, just that we can predict certain things. Photons don't have mass, they dont take up 'space' either, you could I guess interpret them as a vector which had a 2d disc perpendicular to its axis, but there's no volume involved so it doesnt take up space. They aren't concepts you apply to things like photons. On March 24 2012 16:54 UniversalSnip wrote: Can you disintegrate a fundamental particle? It's not like I actually know what any of this means, but particularly that makes me confused about the meaning of fundamental. What are you going to disintegrate it into? Doesn't 'fundamental' imply it doesn't have smaller pieces to break up and fly apart into? Seeing as disintegrate means reduction to component parts, no you cannot disintegrate an electron. Colliding things in a quantum mechanical sense (not a classical sense) isnt as obvious to interpret, what essentially happens is the particles 'meet up' and interact via forces and then continue on their way, although I suppose you could interpret the momentum transfer as being collision-like. For electrons, they arent point like so they can never 'hit' each other, its just interaction. At low energies they simply deflect each other, get a more energy behind this and they emit photons (light) and crank it up to massive accelerator level and you can get other leptons, anything goes as long as you don't violate conservation laws, energy, charge, linear / angular momentum etc, for instance you cant make 4 electrons from two but you can make electron-positron pairs. On March 24 2012 10:54 syth99 wrote: I have been thinking about this a bit since i saw a tv show and someone stated the size of an electron. Why do fundamental particles take up space? if i was to take two electrons and push them together strong enough to overcome their repulsive forces what stops them from taking up the same space? Brief googling found me not much information. Edit: I more so want this to be about why we think things take up space? Photons do not take up any space but when it turns into mass it gains volume? Why? Shows which try to explain complicated physics always make actual physicists cringe, they use concepts which arent applicable (like size) to explain things. This is all well and good when you're just trying to have an idea what to expect when you learn about these concepts, but as I said above, these are all mathematical concepts, learning or trying to understand them without the mathematical grounding is never applicable.. once you learn the maths this would make sense. Your question about electrons isn't really valid, you're thinking about it in a classical sense, you can't 'push' electrons together, they arent solid objects, its like trying to push two clouds together, at which point do you say they collide? As has been said, electrons are fermions so they cannont violate the Pauli principle, but all this means is they can't have the same quantum states but this is not the same thing as position as position doesn't apply to electrons, they aren't in any one place at one time, they are a probability field. Your edit question is pretty complicated, firstly you have to get to grips with how mass comes about (http://en.wikipedia.org/wiki/Higgs_mechanism), its not a question I really feel I can give a satisfactory answer to, sorry. I think most of the questions in this blog come from a lack of understand of the nature of particles and their interactions (which is fine, you need a physics degree to understand them), you essentially have to throw away all your 'classical' conceptions of matter and approach from a more mathematical angle. | ||
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micronesia
United States24779 Posts
On March 24 2012 18:53 adwodon wrote: Seeing as disintegrate means reduction to component parts, no you cannot disintegrate an electron. I should have been more clear than 'disintegration' but can the electrons get converted into photon energy similar to how an electron and a positron would (annihilation) under those types of circumstances? | ||
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surfinbird1
Germany999 Posts
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surfinbird1
Germany999 Posts
On March 24 2012 20:41 micronesia wrote: I should have been more clear than 'disintegration' but can the electrons get converted into photon energy similar to how an electron and a positron would (annihilation) under those types of circumstances? No this isn't possible. You would violate the conservation law of leptonic numbers. The annihilation of an electron and a positron (which is an antielectron!) works because they have opposite leptonic numbers (electron +1 and positron -1), so they can annihilate to photons, which are bosons (leptonic number 0) and ergo the leptonic number was zero before and after the interaction. On the topic of pushing together electrons: Coming from a classical point of view the electric field is proportional to the inverse of the square of the distances. Therefore the work required to push them together would become infinite. Sp it wouldn't be physically possible. But since we're dealing with quantum objects here, the act of pushing doesn't quite work the way classical pushing works. So this view is problematic to say the least. | ||
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Otolia
France5805 Posts
Every other relevant problem is linked either to the particle-wave duality, or Heisenberg's incertitude principle or Pauli's principle, which are tied together by the fundamental equation of particle physics. | ||
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micronesia
United States24779 Posts
On March 24 2012 21:42 surfinbird1 wrote: No this isn't possible. You would violate the conservation law of leptonic numbers. The annihilation of an electron and a positron (which is an antielectron!) works because they have opposite leptonic numbers (electron +1 and positron -1), so they can annihilate to photons, which are bosons (leptonic number 0) and ergo the leptonic number was zero before and after the interaction. On the topic of pushing together electrons: Coming from a classical point of view the electric field is proportional to the inverse of the square of the distances. Therefore the work required to push them together would become infinite. Sp it wouldn't be physically possible. But since we're dealing with quantum objects here, the act of pushing doesn't quite work the way classical pushing works. So this view is problematic to say the least. This makes perfect sense and is consistent with what I already know about particle, but I can't help but feel like if you shot an electron with a 'bullet' with 10^1000000000 joules of energy you wouldn't still have an electron afterwards. | ||
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surfinbird1
Germany999 Posts
On March 24 2012 21:55 Otolia wrote: There is no need to invoke Pauli's principle here. Fermions take space (as defined with the conventional 3 dimensions) because they have a mass. Every other relevant problem is linked either to the particle-wave duality, or Heisenberg's incertitude principle or Pauli's principle, which are tied together by the fundamental equation of particle physics. How much space do they take up? I'm pretty sure they're point particles. And they don't have a classical volume in that sense. On March 24 2012 22:26 micronesia wrote: This makes perfect sense and is consistent with what I already know about particle, but I can't help but feel like if you shot an electron with a 'bullet' with 10^1000000000 joules of energy you wouldn't still have an electron afterwards. Haha, I know. Sometimes Quantum mechanics just fucks you up :D But if it consoles you in any way, the particles don't actually meet in a classical sense. There's no billard ball collisions. They're just interacting/scattering. It's pretty freaky to be honest. | ||
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felisconcolori
United States6168 Posts
^^^ Also, yeah... at that level, there is not a physical interaction because all of the various forces are stronger and interaction takes place further out (if there is a "physicality" to begin with on that level - most of the "solid" things are merely empty space anyways, and the "physical" bumping my palm exhibits against my face may be just the interaction of atomic-scale (or sub-atomic scale) forces). Of course, if you want the Quantum Physics answer - MAGIC!! (IE, we know that this happens according to this mathematical formula, and the observations hold up for validation, but it's still really a "spooky" field.) The long answer probably involves math I cannot even read, let alone comprehend, and may fill many a chalkboard. | ||
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adwodon
United Kingdom592 Posts
On March 24 2012 22:26 micronesia wrote: This makes perfect sense and is consistent with what I already know about particle, but I can't help but feel like if you shot an electron with a 'bullet' with 10^1000000000 joules of energy you wouldn't still have an electron afterwards. I'm pretty sure at high energy e-e- collisions you can get other leptons, or at least neutrinos (due to oscillation they make conservation laws a bit weird though), if it doesn't violate conservation laws then it could happen in principle, but ill also say that I'm not sure about that. ee collisions are fairly boring though, e+e- (as you can produce hadrons from these collions, oddly enough) are more studied now, or lepton hadron collisions. If anyone's curious this is what a pp collision looks like (prepare to have your mind blown): + Show Spoiler + ![[image loading]](http://a6.sphotos.ak.fbcdn.net/hphotos-ak-ash4/422900_10151374105760187_821855186_23352866_78286757_n.jpg) My masters thesis is about event generators used to predict these kinds of collisions, working on ep collions at HERA at the moment  | ||
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whatthefat
United States918 Posts
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Vlare
748 Posts
Super basic | ||
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whatthefat
United States918 Posts
On March 25 2012 04:35 Vlare wrote: Pauli exclusion principle. Super basic I don't consider that a very satisfactory explanation. First off, it's only applicable to the case where there are multiple particles in a quantized system, and even then it says nothing about their spatial distributions within their respective states. Moreover, it doesn't tell you anything about the spatial distribution of a single particle (either in a potential well or in free space). | ||
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ymir233
United States8275 Posts
I don't think electrons at higher levels of modeling are described geometrically (that is, by their volume as if they were just balls in vacuum) so much as they are energetically (in quantum states). I mean, if you look at what they do in quantum mechanics (I only took an intro course), they talk less about theoretical electron volumes and more about Stern-Gerlach machines and raising/lowering operators that deal with energy/orientation states/probabilities. As for the quantum states themselves, the Pauli exclusion principle for electrons is sufficient enough because it just says that half-spin fermions can't be in the same state together. As for the derivation, there's some random (not too bad) showing on Wikipedia involving linear. But I probably wouldn't get it because while I can understand linear/Dirac notation I fail at probabilities. As for how they create free space, leading to chemical properties such as hydrogen bonding and elastomer synthesis, that's just essential electron-to-electron repulsion (the whole Born repulsion term) IMHO. Theoretically electrons could be near the same space, but it would take a shitton of energy to overcome that repulsive term (esp. since if you look at it, the term is proportional to r^(-b), where b is like 4-7 or something). | ||
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