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Magnetic Monopoles?

  1. Oct 5, 2011 #1
    Magnetic Monopoles??

    1. The problem statement, all variables and given/known data

    why do such things exist?? how exactly do they work? when cutting a bar magnet into half, both halfs have their own north and south pole right??

    found this excerpt on the internet(i'm currently learning magnetism )If you've ever seen a compass, you will remember that it has the interesting property of always pointing to the north. This is because there is a magnet on the end of the compass needle. If you bring a bar magnet near to a compass, you will notice that the needle repels from the bar magnet's north pole. (my question is, how do we even know which pole is the north pole of the magnet?)This means that the compass needle is also a north pole. Like charges repel. So if the magnet is north, it should point AWAY from the north pole of the earth, since like charges repel. The answer to this little riddle is simple- the north pole of the earth is actually a magnetic south pole. (another question: why must it be this way? why can't the south pole of the earth be the magnetic north pole?)
     
  2. jcsd
  3. Oct 5, 2011 #2

    PeterO

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    Re: Magnetic Monopoles??

    60 years ago, magnets were often painted blue one end and orange/red the other. Ithink the convention was that the North Pole is the red/orange one.

    The most recent magnets I have seen in the class room have N moulded into the side of one end - that pretty well says it all.

    The North Pole of the Earth is:

    The Pole of the Earth to which the North Pole of a suspended magnet will point towards.

    That statement is too long so all bar three words are generally left out. Those three words are the ones in Red.

    In other words:

    The North Pole of the Earth is the North Pole
     
  4. Oct 5, 2011 #3

    NascentOxygen

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    Re: Magnetic Monopoles??

    They don't.

    It can be, and in the past has been, and it will be again. The earth's magnetic poles reverse periodically. Recently the poles have been wobbling around more and more, and it is thought this may be preparatory to a complete pole reversal.
     
  5. Oct 5, 2011 #4
    Re: Magnetic Monopoles??

    but my teacher asked us if there were such things today.... and the internet says recently scientists have found that there are magnetic monopoles??

    ahh... i see. thank you!
     
  6. Oct 5, 2011 #5
    Re: Magnetic Monopoles??


    huh?? the north pole of the earth is the north pole? isnt there only one north pole?
     
  7. Oct 5, 2011 #6
    Re: Magnetic Monopoles??

    The geographic north pole and the magnetic north pole are not to be confused.

    What Peter means is that the MAGNETIC north pole of the earth is, by definition, the direction where the north pole of a magnet will point. It has been shown that it switches locations every once in a while among earth's life.

    The geographic north pole is the geographic north pole, always will be. In other words, the geograpgic north pole and magnetic north pole didn't always near match.
     
    Last edited: Oct 5, 2011
  8. Oct 5, 2011 #7
    Re: Magnetic Monopoles??

    ahhh i seee. thank you! so are there magnetic monopoles?
     
  9. Oct 5, 2011 #8
    Re: Magnetic Monopoles??

    No..
     
  10. Oct 5, 2011 #9

    phinds

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    Re: Magnetic Monopoles??

    The term "North" is a name that we humans give to a particular direction. It was discovered some time ago that the earth has a magnetic field with the standard two poles. It has been known since ancient times that a compass points in a particular direction, which happens to be almost lined up with the geographic North Pole, so it was naturally enough stated that a compass points North. Put all that together and you get the very natural convention to call one of the bar magnet poles the North pole, and by convention to then call the other one the South pole. It's just a naming convention.

    More recently it has been discovered that the earth's magnetic field reverses every so often, so one of these days all the map makers in the world (if we still have maps when it happens) are going to be REALLY pissed off because all their maps will have to either be redrawn upside down or have the "N" and "S" names switched on the compass rose.

    Magnetic monopoles are mythical beasts, much like unicorns and dragons, although to be fair physicists HAVE looked to magnetic monopoles but only alchemists have looked for unicorns and dragons.
     
  11. Oct 5, 2011 #10

    NascentOxygen

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    Last edited by a moderator: Apr 26, 2017
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