in Quantum Mechanics how can an atom be in two places at the same time? (as long as you don't look at it!?!)
79068
Your question implies that an atom has a position when it is not being measured; the correct answer is that it does not even HAVE a position when it is not being observed.  This was shown by J.S. Bell who proved that "hidden variable" theories (that is, for example, those that claim an atom has a position when not being observed, but that we simply can't know what it is -- thus the hidden) can not adequately explain quantum mechanics.\n\nWhat it does have, however, is a probability distribution (called a "wavefunction" in QM jargon) which will tell you the probability of detecting an atom at a certain location when you make a measurement.  [To be precise, the absolute-square of the wavefunction is the probability distribution, but don't worry about that.]\n\nWhen you make a measurement the wavefunction is said to "collapse" to that point so that subsequent measurements made immeditially afterward will yield the same result; that is, the probability of finding it at the same location again approaches 100% while the probability of finding it elsewhere approaches 0%.  This distribution, however, will eventually spread out again.\n\nI hope that helps.
950457
yes you are right.. there are two sets of electrons
251335
It can be "explained" with quantum mechanics. If you can find the movies of the lectures given by Richard Feynmen in New Zealand, there are 4 lectures if I am correct, In the first lecture he explains it very well in Laymans terms.\n\nIt takes a fair bit of explanation so I won't attemp to relate it here.
870020
While photons don't have any force-mitigated interactions, there can be interference.  Matter (fermions) has the Pauli Exclusion Priniciple preventing, say, two electrons from being in the same spin-state in the same sub-orbital...there's a destructive interference term in the probability wave equation that comes from their half-spin states.  \n\nSimilarly, there's an inverse sort of "Pauli Inclusion Principle" for bosons (which have integral spin states and includes photons) to constructively interfere in the wave equation such that there's an increased probability for them to be in the same place at the same time.  \n\nOne might be able to, as you say, 'channel' this and force them to work together by creating an energetic population inversion of electrons ready to emit, then sending through a photon of the proper wavelength to produce a cascade of stimulated emission...Oh wait, that's a laser.
63744
B only seems impossible because you're looking at it from a small, everyday perspective.  Read a book on quantum phenomenon and you'll discover that particles literally appear out of no where everyday, and we take this as completely normal.  The Universe and Everything is far more sophisticated than you're giving it credit for.
754961
An atomic particle can be represented either as a particle or as a wave; such a particle has both properties simultaneously and with appropriate experiments you can see either property.  Electrons, for example, act as particles when you use them to light a CRT screen, but if you set up an apparatus with two slits and throw electrons at them such that they could go through either slit, you see a diffraction pattern as from a wave.  A consequence of this is the Heisenberg uncertainty principle: you cannot determine both the position and momentum of a particle with unlimited precision: the product of the uncertainties of the two measurements must be at least as large as a small number called Planck's constant.  For more on this, see any textbook on quantum mechanics.
306636
For the nth level, the quantum numbers left are l,m, and s.\nWe have that l goes from 0 to n-1 and is an integer, and m goes from -l to l and is an integer, while s takes on two values +-(1/2). Pauli's exclusion principle says that no two electrons can have exactly the same quantum numbers. So there is one electron for each valid choice of l,m, and s. Now count the possibilities.
375887
I think what you're asking is why when a photon is detected at one location it can never be detected anywhere else even though it seems to be (and is) a wave rolling over many detectors simultaneously.\n\nFirst it's necessary to dispose of the canard that a photon is a particle in the classical sense, whose position is hidden or unknown until it transpires (becomes known) by means of a detection event. That's false even though standard terminology such as "detection", "measurement", "uncertainty" seem to support it. A photon is an elementary excitation of the electromagnetic field described by a wavefunction over space.\n\nThe photon initially can be described by a superposition of states:\n\n|s1> + |s2> +...\n\nwhere for example |s1> is a state in which the wavefunction is nonzero only near detector 1, in |s2> it's nonzero only near detector 2, and so on. Wherever the photon wavefunction overlaps the wavefunction of a charged particle there's an interaction. If the photon wavefunction overlaps an electron in detector 1 there is some evolution into a state in which the photon is absorbed (destroyed) and an electron is ejected from the atom triggering the detector, so the above state evolves into something like:\n\n|d1> + |d2> + ...\n\nwhere |d1> is a state in which detector 1 has registered an event, and so on.\n\nIn each state |di> there is no possibility that any detector other than i has registered an event since it evolved directly from |si> in which the photon wavefunction was nonzero only near detector i and zero everywhere else. So in each of the component states there is only the one detector which registered an event and no photon left around to trigger any more. Because the states |d1>,... are forever orthogonal to each other we can focus on just one and pretend the others don't exist. That's the idea behind the Copenhagen interpretation.\n\nTechnically a single photon cannot be detected without destroying it, but an electron can be. After the electron detection process the states |d1>,... etc. of the world would include various components of the original electron state in each one. Once two components of the electron state or wavefunction have become hooked or entangled with separate orthogonal states of the external world they can no longer interfere with each other.
1111040
According to quantum mechanics, electrons can be represented by wavefunctions, from which the electron density can be determined. Each electron has its own wavefunction, which is called an orbital. The exact momentum and position of an electron cannot be simultaneously determined. This is a limitation described by the Heisenberg uncertainty principle, which, in this instance, simply states that the more accurately we know a particle's position, the less accurately we can know its momentum, and vice versa.  So, exact postion of an electron impossible to determine.  Thus electron can be two places at ones.
1159743
Quantum superposition suggests it would exist in multiple places but in an experiment the heisenberg uncertainty means it can only ever be measured in one place (observing it causes its wavefunction to callapse to a single location).
190186
Schroedinger said that the cat must be in a superposition of dead and alive states before the observer opens the box because the cat's fate is tied to the wave function of the atom, which is itself in a superposition of decayed and undecayed states. Of course, the cat can't be dead and alive at the same time, wave functions don't give a complete view of reality and that's what Schroedinger tried to say with this paradox.
972422
Looks like only one person got the right idea so far so I will try to underscore that.\n\nEveryone who says that it is possible to have NOTHING inside a box if you have a total vacuum has ignored quantum theory which has proven to reflect reality extremely well.\n\nThe uncertainty principle allows energy to be borrowed from the vacuum for a very short time.  The vacuum is seething with pairs of "virtual" particle+antiparticle pairs that are created with this borrowed energy.  They pop into existence and then annihilate with each other extremely quickly.\n\nSo no, as far as anybody knows we have strong reason to believe that it is impossible to have absolutely nothing inside a box because something is always popping up everywhere in space.  Maybe if you had a very small box and very big luck luck it would be empty just for the tiniest period of time.
788044
i can assure you that  the answer is \n\nA. the Bohr model of the atom, with discrete orbits. \n\ni have been analyzing this work  for 3 years.\n\n\np.s the answer is so funny C."C. the Einstein model of the atom."
1126630
Theoretically, it'd be trapped inside the sphere forever. In practice, mirrors are not perfect. The material the light bounce off would absorb energy, allow light to "leak" through, etc etc.\n\n\nsomething related.. maybe...\nThis remind me of one thought experiment to determine the position and energy of an electron simultaneously by putting the electron in a box and making the box smaller and smaller. Heisenberg's uncertainty principle said u cannot determine both the momentum and position of the electron infinitely accurately at the same time. The idea is to make the box so small eventually the electron would be confined to a fixed position with 0 velocity and known position. But however, by making the box smaller and smaller, the wall of the box push against the electron, giving it more and more energy and when u thought u have zoom in on its position, the electron would have so much energy it'd simply burst out of the box.
475479
here's my guess --\nthat these particles are somehow "connected" . that they do not violate casuality (this one is proveable) or locality....somehow.
538049
Yes.  In fact protons even from two different elements are indistinguishable.  This is a fundamental property that is quite interesting, and it results in some very odd behavior.
484232
According to quantum mechanics, an object exists for you only when you are aware of its existence. Otherwise it is a probablitly.\nI will give an example: If you look away from your computer to say a TV, then the computer object has ceased to exist and TV has started existing. But the you who is looking at TV is different from the previous you who was looking at the computer, because when the computer ceased to exist, so did you and so did the universe frame containing you, computer and the elements like light that made looking at computer possible. Now you, TV and the process of looking at TV is happening in a different universe.\nNow if you again turn your head to look towards computer, you will cease to exist with the TV universe and enter a third universe identical to the first universe. But how do you see the same computer if you are entering the new universe, then this is one of the less known uses of our memory, that is being used by the universe to make fools of us.