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Question on Magnets

  1. May 31, 2008 #1
    How are magnets made? I mean how are they made to produce a magnetic field? How are some magnets made to attract and some to repel?

    And just to know:-

    Does magnetism got some connection with gravity? Because practically we can notice some similarities.I think I am asking an answer to silly question but this stuff has been bothering me for quite a number of days.
     
  2. jcsd
  3. May 31, 2008 #2
    Magnets can be made but they can also naturally occur.
    Magnets that are made are made using coils of wire that make something called a solenoid. There are also electromagnets that can be turned on and off and work much the same way as a solenoid.
    All magnets attract and repel at the same time. All magnets have a North and a South pole. If you put two North poles or two South poles together they repel but if you put a North and a South pole together they attract. You may have heard the saying opposites attract. That is the case here.

    Magnetism is a different force to gravity.

    The most magnetic naturally occurring substance is pure iron.

    If you want any more info just ask.
     
  4. Jun 1, 2008 #3
    Thanks, but iron is not magnetic is it? Though magnets get attracted to it can we say that it produces a magnetic field ? Can you please tell me how magnets occur naturally? I mean in the case of the man-made one the solenoid is produced by passing an electric current through the coils, but what about the natural ones? Is some natural system in the universe dependent on magnetism?I mean I know that Earth and some of the other planets have a magnetosphere, but is that the reason why magnetism works in the Earth? Does that mean that magnets won't attract in Venus?
     
  5. Jun 1, 2008 #4

    russ_watters

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    Staff: Mentor

    Iron is ferromagnetic: http://en.wikipedia.org/wiki/Ferromagnet

    In other words, you can turn an ordinary piece of iron into a magnet and it will stay a magnet for a very long time.
     
  6. Jun 1, 2008 #5
    I am not entirely sure as to why iron is magnetic but I think it has something to do with its electron structure.
     
  7. Jun 1, 2008 #6
    Magnets are made by exposing material, either powdered under pressure as in a manufactured sintered magnet, or as a predisposed object such as a nail or other ferrous material to a force which aligns thier internal structure to impose and retain a magnetic field.

    The simplest way is by taking ferro (iron based) magnetic materials such as steel, iron, or it's composits and exposing them to a short, but very intense field as is found in the inside of a solenoid. The strength of the magnet made depends to a great extent on the materials used and thier composition.

    Please note that not all material is magnetically enhancable. Materials like brass for instance are largely magnetically inert. Others, such as Bismuth, are anti-magnetic. Which is to say that they repel all magnetic fields.

    As to your last question about magnetism and gravity, while they share similar properties vis-a-vis attraction over a distance, they are different phenomena.
     
  8. Jun 2, 2008 #7

    I believe that microscopically it is. An untreated piece of iron is probably made of tiny "grains" each of which is a magnet (iirc they are called "magnetic domains"), but these grains are themselves not all aligned with each other. I think a possible method to help the domains order themselves goes through melting and slowly solidify the iron possibly with some external "help" such as a magnetic field to "suggest" the newly-forming domains to form in a certain direction rather than randomly.

    (I should definitely go back and pick my old solid state physics book...)
     
  9. Jun 2, 2008 #8
    After all, isn't each electron like a small magnet?
     
  10. Jun 2, 2008 #9
    As long as it orbits or spins, yes.
     
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