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The non-homogeneous mix of magnetite, iron, oxygen and other trace elements in lodestone, the only naturally occurring magnet, is what makes it permanent (hard). Pure homogeneous magnetite or iron is not permanent but a temporary (soft) magnet. An ideal permanent magnet is a heterogeneous alloy with high coercivity, meaning it is difficult to demagnetize. These alloys have elements with atoms that can be induced to point persistently in the same direction (ferromagnetic) making them strongly magnetic. Only three--iron, cobalt and nickel--of the 100 elements in the periodic table are ferromagnetic at room temperature. Alloys are made magnetic by exposing them to magnets or electromagnets.
Extract afrom a loudspeaker.
Use tongs to heat the steel nail over a stove, allowing atoms in the nail to move around more freely.
Use the compass to determine the Earth’s magnetic north and south poles. Align the steel nail in the North-South direction and place the loudspeaker magnet just north of the nail.
Hit the nail with the hammer until it is cool, at least 50 times, making sure the nail remains all the while in the north-south direction. The atoms within the steel nail will be shaken to line up with the magnetism of the nearby magnet.
Tips & Warnings
Other common household items, such as the microwave oven, also have strong permanent magnets that can be used instead of the loudspeaker magnet. The stronger the magnet, the better the result.
The Earth's magnetic field alone is capable of weakly magnetizing the steel nail, without use of the loudspeaker magnet.
Choosing a strong ferromagnetic material to magnetize will yield better results.
Children must have adult supervision when doing this project.
Magnets are capable of erasing magnetically stored data on such things as video tapes, hard drives and credit cards.