What does north and south mean on a magnet?

  1. I understand the "north" is where to field is "coming out of" and south is where it returns, and i can see how two magnets would repel and attract. However when electrons or protons are brought near magnetic fields they are deflected. Why?
    What determines which direction a negativley charged particle would deflect towards? Is "south" negative and "north" positive?
    I cant seem to type this into google in a way that wouldnt bring up links to "magnets for kids" or similar.
  2. jcsd
  3. Simon Bridge

    Simon Bridge 15,474
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    Welcome to PF.
    The "north pole" of a magnet is the end that would, if left to it's own devices, point along the Earth's surface towards the position on the horizon closest to the pole star (close enough for simple navigation anyway). Thus it is properly called the "north-seeking pole".

    Charged particles are not deflected by magnetic fields unless they are moving, in which case the direction deflected is 90deg to both the velocity and the magnetic field.
    At beginner level you can think of moving charges as electric currents - electric currents have a magnetic field around them which can interact with other magnetic fields.

    In more advanced levels, electricity and magnetism are understood as different aspects of the same electromagnetic interaction - so charges and magnetism are closely related.
    Last edited: Feb 27, 2014
  4. SteamKing

    SteamKing 10,967
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    If you google "magnetism", you will get a wiki article on magnetism, and there is quite a detailed discussion of particular forms of magnetism and magnets contained therein.
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