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Can a magnet be made by friction?

  1. Aug 2, 2006 #1
    at work, i was using a tool which is used to tight objects to each other, and after a while, i put it on the table, and small steel pins sticked to it.

    the steel tool, i guess that every time i tight the tool to the metalic objects there was friction, and somehow it became a magnet.

    and no, it is not electric, i checked other materials than steel. and no, it wasnt magnetic before.

    i never heard of such phenomenon... i need someone to direct me to an article about friction and magnetism...
     
  2. jcsd
  3. Aug 2, 2006 #2

    Danger

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    I'm not sure about that. Is there a chance that it came into contact with a permanent magnet, such as being set down in contact with a magnetic screwdriver, or suffered an impact like being whapped with a hammer to make something tighter? If you hold a piece of steel rod pointed toward magnetic north and smack it with something, it becomes magnetized.
     
    Last edited: Aug 2, 2006
  4. Aug 2, 2006 #3
    what about hiting a hamer with it while its pointing to magnetic south?
     
  5. Aug 2, 2006 #4

    Danger

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    Which would leave the other end pointing where? :tongue:
     
  6. Aug 2, 2006 #5
    but then the end in question wouldnt become southerly magneticiesed

    anyway what 'other' end?
     
  7. Aug 2, 2006 #6

    Danger

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    Whaddaya mean, 'what other end'? :confused: If you've ever seen a rod with only one end, you must live in an Escher painting.
     
  8. Aug 2, 2006 #7
    well, here in israel, we call it japka, i dont know the english name for it.

    its a tool like a player, which is used to pull two surfaces togather, real tight.
    it locks after the surfaces are tight.

    also it have been banged some, though it wasnt what i was trying to do with it...(i droped it on the metalic table every time i finished working with it)

    there were no magnets nearby, though i think i would retest it again... its realy wierd, im not physics student, but i know a thing or two about magnetism, and i never heard of such thing.... i should check the enviorment again, and try to redo that, i think i should bring a compass..
     
    Last edited: Aug 2, 2006
  9. Aug 2, 2006 #8

    Gokul43201

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    This may be due to the magnetomechanical effect (something like an inverse of the magnetostrictive effect), but I'd be surprised if the weak terrestrial field of the earth is sufficient to produce a noticeable effect.
     
  10. Aug 3, 2006 #9
    it seems like the steel tool carries the magnetic aura for a long time, actully i didnt fell like it was reducing in time at all, i isolated it from other metals, it stayed magnetic just the same.

    so i guess that its enough that a screwdriver with a magnetic head was close to it a week ago or so, and it would be magnetic...

    odd... i never thought that magneticly induces steel last long as a magnet...
    i even banged it a bit, it didnt turn off the effect... maybe banging only works on compressed powder magnets...
     
  11. Aug 6, 2006 #10

    Gokul43201

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    Oh yes, it can, depending on the type of steel. Only certain kinds of steel (silicon steels and some ferritic stainless steels) are magnetically very soft. Other kinds will retain a considerable remanent magnetization for a long, long time.
    No, banging works on other materials too, but what is important is how hard you banged it, and how many times.
     
  12. Aug 7, 2006 #11

    LURCH

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    Friction is how magnetism was first discovered (or "noticed"), wasn't it? People found that if you rubbed certain materials, like waxes or you hair, against certain other materials, like cat's fur, they would become attractive and you could pick up bits of string or make your hair stand up and "reach toward" other objects. It's like what happens when you rub a balloon on the carpet or on your head, and then stick it to the cieling.

    Friction between two objects can cause ellectrons to "rub off" from one object onto the other. This leaves both objects with a slight charge. If noe of these objects is a tool that brushes against a large number of metal objects over time, then the individuall objects might pick up a slight charge as a result of that contact, but the tool would accumulate a charge equall to the combined charge of all the instances of contact.

    I suppose this would meen that all the parts you've assembled using that tool also have a slight magnetic filed, and that the power of the tool's magnetic field is almost exactly equal to the combined power of the fields of all those parts.
     
  13. Aug 7, 2006 #12

    berkeman

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    I think you're confusing static electricity (which can be separted with friction and rubbing as you describe) with magnetism. You don't get any magnetic effect by rubbing materials together -- that's static electricity. And I doubt that any static electric effect accounts for the attraction of ferrous bits to this poster's metal tool. He said that he was setting it on a metal table, after all, so static charges will not be staying put on the tool.

    The pounding theory with the tool pointing toward one (:biggrin:) of the Earth's magnetic poles sounds like the most likely explanation at this point.
     
  14. Aug 7, 2006 #13
    i think u should rethink that...
    try pulling ur hairs with a magnet, and redo that with arubbed object, or a CRT tv screen...

    im anxious to hear the results...
     
  15. Aug 7, 2006 #14
    nope, its a workshop... it could have easly been a magnet around to induce it.
    when i saw the the steel hold the magnetic qualities for long, a thing which i did not know, i convinced myself that it probably was like that before i used it...
     
  16. Aug 7, 2006 #15

    berkeman

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    Well phhhtttt. That's not what you said in your original post. But I'm glad that you figured it out, and we all have an experiment to do now pounding the heck out of steel bars in our home workshops....:biggrin:
     
  17. Aug 8, 2006 #16

    Danger

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    Let me know how that works out for you; I have a life. :tongue:

    Tuvia, the item that you describe is generically called 'locking pliers' over here. The most famous brand-name, Vise-Grip, is usually used casually in reference to any of them.
     
  18. Aug 8, 2006 #17
    ty... here we call it japka, it aint hebrew thats for sure. i think its arabic.
    but i guess that has nothing to do with physics...
     
  19. Aug 8, 2006 #18

    Gokul43201

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    Whaa? Vise-grips are called 'locking pliers' !!?? :wink:
     
  20. Aug 9, 2006 #19

    Danger

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    :confused: They are here. Not in the US?
     
  21. Aug 9, 2006 #20

    berkeman

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    I think Gokul was just funnin' with you.:wink:
     
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