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What IS magnetic force?

  1. Jul 11, 2012 #1
    Noob, apologies to all.

    What is magnetic force? I can calculate it, and know that it is perpendicular to the motion of an electric force, but what is it? Just because I can calculate it does not mean that I know what I am calculating.

  2. jcsd
  3. Jul 11, 2012 #2


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    Staff: Mentor

    A force is just an influence that causes a change in an object. A magnetic force is simply a force arising from an interaction between the magnetic properties of charges. Does that help?
  4. Jul 11, 2012 #3
    I believe that you have just asked a question that appeals to the subject of the philosophy of science. Such questions are not about the description of nature but on the why's of nature. Scientists have not been able to explain why we observe but has ony been able to describe what we observe. While we can describe the force on a charged particle we still don't know why there is a force exists or why it does what it does.
  5. Jul 12, 2012 #4
    Drakkith: that does actually help to put things in perspective, I suppose I have accepted the reason for other forces while not understanding where they arise from either.

    Boston Guy: fair enough, I think that I have simply accepted electric and gravitational forces, but haven't quite accepted magnetic forces yet. Obviously I know they exist, they are directly observable, it is just much harder to envision because I have a chemistry background. Almost everything I've been exposed to so far has been positive and negative electric charges, and even when we did a magnetism experiment, we talked about it in terms of charged ions moving with the magnetic field.
  6. Jul 12, 2012 #5
    One way that might help is to go over electrodynamics, where the electric and magnetic fields are sort of unified into one single electromagnetic field tensor. It involves a bit of maths and some time, but it does shed some light on what's going on. In fact, it involves a lot of maths and a lot of time.
  7. Jul 12, 2012 #6
    In Special Relativity, the laws of magnetism pop up naturally from the laws of electricity.
    You can check out Griffith's introduction to electrodynamics, Ch 10...
  8. Jul 12, 2012 #7
    It's true that we do not know what exactly is going on "in reality"; electric and magnetic fields are just models. However, a magnetic field is itself an effect of moving electric charges. So, if you you can intuitively "accept" or understand the existence of such charges (at least as a model) and the fact they can move, then the intuitive understanding of magnetic force isn't far away. :smile:

    For the more philosophical aspects, see also the following thread from post #40:
  9. Jul 12, 2012 #8
    True, I think that I just need to do as Mikey suggests and practice a little. Morgoth, I don't have the book but if it's required for a class or I find it at a good price I will definitely take a look.
  10. Jul 12, 2012 #9
    I just put that book's name because I have it...
    I guess any book that has to do with electrodynamics, and contains special relativity, will have it...
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