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Magnetism on tapered surface

  1. Nov 15, 2008 #1
    I have a pair of scissors. The blade is about 1.5 cm wide on one end (near the handle), and it tapers down to nothing after about 7-8cm. The blades are about 3mm in thickness. It's been magnetized, meaning, I guess, I've stuck a magnet on it a few times. I'm exactly sure how or why there is such a lasting residual effect, or how to get rid of it, but that's another topic.

    Anyway, when I take something magnetic, like a stainless steel keychain ring, and hold it near the scissors, it is magnetically attracted much more so at the very tip of the scissors rather than anywhere else on the blade. I can tell this by feeling how hard I have to pull to get the keychain away from the scissors. It's much harder to lift it when its stuck to the tip than it is if its just a couple of cm away from the tip. Near the base of the blade it's barely attracted at all. The same applies to the edges of the blade.. it's not attracted to the edge of the blade unless its near the tip.

    I wonder, how can the shape of the blade make it more magnetic on one end than the other? What would happen if I made the tip of the blade extremely narrow, would it become infinitely magnetic? Does the blade thickness factor into this, as well?

    Thank you all for your input :)
  2. jcsd
  3. Nov 16, 2008 #2


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    The scissors are magnetized along their length, just like a bar magnet. The magnetic lines of force travel along the metal and exit at the ends, which is why you feel the greatest force there. Here is a diagram showing the concentration of lines at the magnet ends ("poles").
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