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Please explain to me this:

What is the physical mechanism of the field and atraction force; in which way a force (electro, magnetic or gravity) is transmited between two objects? I will try to explain that question with a few sub-questions (basicly the same ones): On the extreme basic level, the question is: how two particles (proton and electron) atract each other? I know they have opposite charges, but how that charges atract each other? How they "comunicate" that information? How they "produce" atraction force? On the other hand - is it the same mechanism with gravity force? How two bodies "comunicate" their masses? How they start to move toward each other despite their inertial masses? Where that energy come from? What is that force? I know it's a "bit" messy question, but what is the essence of that atraction?

Thanks a lot. Boris

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    $\begingroup$ Ever try separating an iron ball from a strong magnet? Uses a lot of energy, doesn't it... $\endgroup$ – DJohnM Jan 24 '15 at 21:28
  • $\begingroup$ Why should we not compare this with gravity? :) How is it different? Something sets up a field of some sort. And something else is attracted. For me, intuitively, all fields essentially work the same way - they just work on different "objects". (Except of course that gravity only attracts, while a magnetic field, an electric field etc. can also cause repulsion) $\endgroup$ – Steeven Jan 24 '15 at 22:57
  • $\begingroup$ Think about this: Remove the table, and everything else than the magnet and the ball. The ball is moving towards the magnet, but the magnet is also moving towards the ball. So which object gives the "energy"? The energy is not from either body, it is from the combination. From the system. We call it potential energy. $\endgroup$ – Steeven Jan 24 '15 at 23:25
  • $\begingroup$ Thank you for the answer. I think we should not compare gravity and magnetic field in means that magnetic atraction happens only between metal objects - it means that nature of that field is very different than of gravity field. Second: I don't think that both the magnet and the ball gives energy. Why? If we put 2 balls together - nothing will happened. It means that the magnet is one who gives energy. Anyway, my questions are still the same: 1. is this energy endless? 2. what is the physical mechanism of that atraction force? $\endgroup$ – zagreb boris Jan 26 '15 at 22:14
  • $\begingroup$ Due to the massive edit, the linked duplicate no longer fits for this post. However, it now seems to be a duplicate of this question. $\endgroup$ – Kyle Kanos Jan 27 '15 at 0:43
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First of all, welcome to SE :)

Now, there's a misconception that magnets create/spend energy. They don't really. Yes, the ball did use some energy to move BUT that energy was NOT created by the magnet. Magnetism is NOT caused by some sort of 'active' energy creation scheme that goes on in the atomic level. Quite surprisingly, it's a state of artificially induced equilibrium at the level of "crystal domains". Now it's a bit difficult to go into the specific details but let's give it a try ..

Answer #1: The short story is that magnets are composed of lots of what's called "domains" which are made lots of atoms which in certain materials like iron can align their "magnetism" altogether towards a specific direction. Now in an unmagnetized piece of iron, these "domains" point their collective "magnetism" towards random directions. In essence they align in a way that's the easiest for them to maintain; which in physics we say that's it's the way that requires less energy. The following link shows an image of these unmagnetized domains as seen under a special (Kerr) microscope. The alternate colors you see in each crystal shows the orientation of those domains. Now when the material is magnetized, the domains will mostly have one color (black or white, depending on the magnetization direction) but in essence they will NOT create nor loose anything. They will simply realign themselves.

Answer #2: This is a tough one. Believe it or not, magnetism is really electrical in nature. Yes, we need to go into the quantum level to accurately explain it but if we want a more "everyday" explanation, then it's safe to say that the magnetic force in your case is really the collective attraction of unpaired moving charges at the atoms of both the magnet and the iron ball.

I can't really put it any simpler than that.

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  • $\begingroup$ thanks for answer. I understand your explanation of domains. My question is: what is the physical mechanism of that atraction force? How this force is "transmited" from one object to another? $\endgroup$ – zagreb boris Jan 26 '15 at 22:30
  • $\begingroup$ @zagrebboris This goes into the debate of "Action at a distance" which started at the 17th century with Isaak Newton and believe it or not, it still lives on! Early depictions of how a magnet was thought to be working (see images by Descarte) were presenting magnets as a "porous" material emanating tiny magnets which could go through any substance. Ofc none of this is proven right BUT it shows how people were a bit reluctant to accept the idea that one body can exert a force on another without any kind of "physical" contact. To be honest, no one really knows for sure how EXACTLY that happens ! $\endgroup$ – micmanos Jan 28 '15 at 13:25

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