Phil Todd, age 10, of Muncie, Indiana, for his question:
How are magnets made?
Sometimes natural magnets are created when seething volcanic activity occurs in the earth's crust. Other natural magnets sometimes plonk on the ground from the sky above. These strangers are meteorites that suffered through violent adventures, either out in space or on their crashing collision with the earth. It seems, then, that powerful forces are needed to transform a stodgy chunk of metal into a magnet with built in magic.
It is true that the earth uses mighty volcanic energy to make magnets and also true that mighty forces were used to add the magic to meteorite magnets. But smart human minds figured out how to do the trick without using such mighty forces. In fact, you, can make a magnet. Of course, you must start with the right ingredients and refuse to give up when you run out of patience. You need two small bars of iron. One must be a magnet in good working order, with its two opposite poles and its built in magnetic energy. The other is a piece of ordinary iron, maybe a worn out magnet that has lost the power to do its magnetic work.
Locate the two poles of the working magnet and use the piece of plain iron to stroke, stroke, stroke from pole to pole always in the same direction. If the plain iron happens to be a worn out magnet, it helps to know which were its north and south poles. You can recharge it faster if you stroke from the old and new north poles toward the old and new south poles. You can also magnetize a piece of metal ::; placing it in the magnetic field around a large magnet and using a hammer to tap tap¬tap it until your arm grows tired.
These are simple ways to make small new magnets or to magnetize worn out magnets. Mightier magnets can be made because magnetism is related to electricity. An electric current is surrounded by the same invisible lines of force that surround a magnet. Both these magnetic fields attract certain metals and act in the same way. This trick is used to create a mighty electromagnet that can lift carloads of steel. It is a massive coil of copper wire attached to an electric generator. When the switch is turned on, the current turns the coils into a magnet. It is lowered by a crane to where its magnetic force can attract and grab a fistful of steel. Then the crane lifts and swings it above the new location. When the generator switch is turned off, the electromagnet loses its power and drops its load of steel.
We did not learn to make the best use of giant magnets until the 1900s. This was after scientists discovered what causes magnetic force in certain metals and alloys that include iron and steel, nickel or cobalt. The secret is in zillions of infinitesimal electrons, whirling around tiny atoms. When the electrons of most of the atoms whirl in the same direction, they act like a team. Their united energy create., the invisible force that surrounds a magnet.
On the tiniest scale, whirling electrons create a magnet with a north and south pole around each atom. A bar of iron becomes a magnet when enough atoms are arranged so that the electrons whirl in the same direction and pull together. Scientists suspect that this often happens when substances are frozen almost down to absolute zero, which is about 491 degrees Fahrenheit colder than ordinary ice.