MadSci Network: Physics |
Hi, That is a very good question. The answer is yes, hitting a magnet can reduce its magnetic field. However, it is more likely that it will break a modern magnet into little chunks. The various parts of a magnet are pushing on each other really hard, so they can fly outward pretty fast if you hit it with a hammer. Don't do it! The little electron "spins" that produce the magnetism are coupled to a particular direction in the crystal "lattice" (the three dimensioal arrangement of the atoms in the magnet) by a quantum mechanical energy. This energy is very sensitive to the distances between the atoms. When you hit a magnet, you force a local change in the separations between the atoms. This lowers the magnetic energy and can partially demagnetize the magnet. You can find lots of sites on the web by looking under "magnetostriction". You can do your own demonstration of this effect! Go to a hardware store like Home Depot and buy a very large nail. The one I used is 12 inches long! Magnetize it parallel to the length of the nail by rubbing with a large and strong magnet. The nail should then be magnetized enough to pull or pick up a paper clip. Holding the nail as tight as you can near the point, hit it as hard as you can a dozen times or so. Don't hit your hand!! When I did it, the nail would no longer pick up the paper clip! Good Luck! Let me know how it worked. Fred Jeffers Jeffers@iomega.com
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