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Homework Help: Engaging and Disengaging Magnetism

  1. Jan 12, 2012 #1

    I need a little help trying to determine the possibility of magnetizing and demagnetizing an object. My question is as follows:

    Is it possible to line two different slabs of thick glass with magnetic strips that can be magnetized to one another for the purpose of holding them together where they do not separate without great opposing force but that can also be demagnetized for the purpose of pulling the two slabs apart?

    If there is a way to demagnetize these slabs to allow them to be separated, by what process is this achieved? Is it a reaction that could be activated and deactivated by a button?
  2. jcsd
  3. Jan 12, 2012 #2


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    Staff: Mentor

    Welcome to the PF.

    Electomagnets would work. Is this for a school project?
  4. Jan 12, 2012 #3
    No, actually this is my own personal curiosity :smile: so, in using electromagnets, is it indeed possible for them to be disengaged by using a button? Are electromagnets strong enough to hold two thick slabs of glass together without them separating? Would they separate if the slabs were to be dropped or would they stay in place?
  5. Jan 12, 2012 #4


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    Staff: Mentor

    If you were a sci-fi writer, you might be able to make use of a metal's Curie temperature. You have magnets on one slab, and a metal alloy on the other. Normally they attract. But if you were to heat the alloy above its Curie temperature, it loses almost all of its magnetic attraction until it cools. Unfortunately, the Curie temps of most magnetic materials are probably higher than most glasses can withstand, so you may need to invent a new material. As for the push button, I had in mind electrically heating the metal strip by passing current through it ...

    This could be made to work, at least in theory.
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