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How magnets attract objects mechanically?

  1. Feb 22, 2013 #1
    I've seen many technical explanations relating field theory, but haven't seen an explanation to this date that can clearly explain how magnets attract at a distance. What is the physical medium used to attract and what is the mechanism? Please no elevated technical talk, and no references to books, explain it as if you were seeing it with your naked eyes!!!
     
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  3. Feb 22, 2013 #2

    tiny-tim

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    welcome to pf!

    hi dejesusluisx1! welcome to pf! :smile:

    the explanation is the same as how electric charges can attract (or repel) each other desipte being at a distance …

    if you're happy with that, what is your objection in the case of magnetism? :confused:
     
  4. Feb 22, 2013 #3
    There is no physical medium necessary...no more than sunlight needs a 'medium' to propagate through space. the electric and magnetic field are two closely related entities found in every electromagnetic field...what you observe depends on your relative motion with respect to the field. Sit still with a magnet, you observe a magnetic field; move and it becomes an electric field.
     
  5. Feb 22, 2013 #4
    My textbook asked us an equivalent question phrased as: "how does one object "know" of the presence of another object that it would attract/repel?"

    And the answer is the interaction of their magnetic fields. All magnetic objects "set up" a vector field around them. It's not something we can see in and of itself, we can only observe its effects. It's a bit like gravity in that way - we can't "see" gravity, we see its effects.
     
  6. Feb 22, 2013 #5
    Light is the physical phenomenon responsible for magnetic and electrostatic attraction and repulsion. Light carries momentum from one charged body to another, the direction depends on the sign of the charge. Magnetism is the consequence of relativistic motion (in familiar cases rotational or revolutionary motion) of electric charges.
     
  7. Feb 22, 2013 #6
    I don't think this is true. There is no light between objects or particles atracting electricaly or magneticaly. Light is just the disturbance of the electrmagnetic field.
    Maybe you are talking about QED model, where interaction is explained by exchange of virtual photons, but they are not light.
     
  8. Feb 22, 2013 #7

    sophiecentaur

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    He means Electromagnetic Waves / Fields. Light is a subset of these.
    It is asking too much, I'm afraid, to ask for a "Mechanical" explanation of something that just isn't mechanical. We are supposed to be advancing in our understanding of Physics and, consequently, there will be ideas that don't fit in with the old views. Insisting on an easy explanation of Physical phenomena is just debasing the whole Subject.
     
  9. Feb 22, 2013 #8
    Dr. Feynman was asked the same question. His answer will give you great insight and it is very simple to understand.
     
    Last edited by a moderator: Sep 25, 2014
  10. Feb 22, 2013 #9

    Integral

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    Iron is a shorter path for the magnetic field lines then air. It is the nature of magnetic field lines to be as short as possible. The shortest possible path with the highest density of lines is with the iron as close as possible to the magnet. If they are free to move, the magnet and iron, will seek this lowest energy state, that is the shortest possible field lines.

    That is a very hand wavy attempt at giving you an intuitive feeling for what is happening. I have left several open questions, why is iron a shorter path, and the connection between field lines an energy. The answer to those questions lie in Maxwell's Equations.
     
  11. Feb 22, 2013 #10

    Integral

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    Good video. but it does not answer the question.
     
    Last edited by a moderator: Sep 25, 2014
  12. Feb 22, 2013 #11

    sophiecentaur

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    That video answers the question perfectly. You just didn't listen to what he was saying.
     
  13. Feb 22, 2013 #12

    jim hardy

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    Until i figure it out, i'll say "Aether".
    Whatever free space is made of, it has magnetic permeability μ0. And that number is significant in elctromagnetics.

    Is there universal frame of reference ?
    That we haven't found one yet only says to me perhaps its nature is not electromagnetic.

    but i'm a plodder.

    old jim
     
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