Today's Magnets!
Ines Miraka
Today’s Magnets!
All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field.
Some substances can be magnetized by an electric current. When electricity runs through a coil of wire, it produces a magnetic field. The field around the coil will disappear. The Earth is a magnet. Scientists do not fully understand why, but they think the movement of molten metal in the Earth’s outer core generates electric currents. The currents create a magnetic field with invisible lines of force flowing between the Earth’s magnetic poles.
The geomagnetic poles are not the same as the North and South Poles. Earth’s magnetic poles often move, due to activity far beneath the Earth’s surface. The shifting locations of the geomagnetic poles are recorded in rocks that form when molten material called magma wells up through the Earth’s crust and pours out as lava. As lava cools and becomes solid rock, strongly magnetic particles within the rock become magnetized by the Earth’s magnetic field. The particles line up along the lines of force in the Earth’s field. In this way, rocks lock in a record of the position of the Earth’s geomagnetic poles at that time.
Today magnets are obviously still used. You come into contact with magnets many times in the course of your daily life. They play an important role in a wide range of devices including simple toys, computers, credit cards, MRI machines and business equipment. Magnets range in size from barely visible specks to industrial monsters, weighing tons. Though some are plainly visible, others are often tucked inside the inner workings of appliances and other household, medical and commercial items, doing their job silently and unseen.
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