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Magnetism. I. Magnets: Natural and Artificial. Ferromagnetic – naturally magnetic Examples:. Iron ( F e). Steel (alloy). Cobalt (Co). Nickel (Ni). Dysprosium ( Dy ). Gadolinium ( Gd ). Ferromagnetic substances can lose their natural magnetism if heated at a specific temperature.
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I. Magnets: Natural and Artificial Ferromagnetic – naturally magnetic Examples:
Ferromagnetic substances can lose their natural magnetism if heated at a specific temperature.
Artificial Magnets • Can be made from ferromagnetic substances • Alnico magnets are made with aluminum, nickel and cobalt
Permanent Magnets • Hold on to their magnetism • High retention • Hard Magnets
Temporary Magnets • Low Retention • Tend to lose magnetism easily • Soft magnets • Example: Iron-Silicon alloys
Making Magnets • You can make a temporary magnet by placing a ferromagnetic material in a magnetic field. • You can stroke a ferromagnetic material (like a nail) with a permanent magnet in one direction. This aligns all the north and south seeking poles in opposite directions.
Credit Cards have magnetic strips • Being in contact with a magnetic field will erase the information by realigning/reversing the iron particles. Common demagnetizers include: • pads used to deactivate security devices in new books, CDs, and movies • some security screening machines • Small magnets like those used on the refridgerator • Speakers • Some cell phones, • Magnetic clasps on wallets and purses
A magnet can destroy a hard drive • Magnet on a laptop
A magnet can lose its magnetism By: • Dropping it • Heating it • Striking it
Keeping Magnets strong • Placing a Keeper across the poles when not in use.
Storing magnets in pairs with opposite poles together • Keeping the magnet on a metal like attached to a filing cabinet