Vicki Hauber, age 12, of St. Marys, Pennsylvania, for her question:
What makes a magnet attract and reel?
A metal magnet pulls and holds slivers of steel. So we know that its magical force extends outside the metal. Its two ends are its north and south poles. The north poles of two magnets repel each other. So do their two south poles. But a pair of north and south magnetic poles attracts each other and cling together. The magnetic force that causes these happenings occurs inside the iron magnet and extends outside it.
This mystery takes us down to the mini world of atoms and the tiny particles from which they are made. The same thing happens in all magnets so let's explore the process in a simple little bar magnet. It is made of iron atoms that are all alike. Each atom is a tight fisted nucleus in the center of whirling electrons. The main particles in the nucleus are protons, charged with positive electricity. Each whirling electron has a negative charge, equal and opposite to one proton.
Every iron atom has exactly 26 protons in its nucleus and room for 26 swirling electrons. All its electrons swirl around in the same direction, creating a mini breeze as they go. In a magnet, numerous atoms are tilted so that their electron breezes blow together in the same direction.
Iron atoms are so small that a row of 100 million of them measures about one inch. Zillions of them are jam packed in a small bar of iron. And each atom creates its tiny breeze of swirling electrons. If the iron bar is not a magnet, its atoms are tilted so that their electron breezes whirl in different directions and cancel each other out.
One tiny electron breeze amounts to almost nothing at all. But when Zillions of them whirl together in the same direction, they whip up quite a storm. In a magnet, numerous atoms are arranged so that their electron breezes blow together as a team. Together, they create the magnetic force that extends outside the magnet. This force is not the same as the positive and negative charges of protons and electrons.
When zillions of electron breezes inside the magnet blow as one, their magnetic force extends outside the metal and loops in lines between the magnet's two poles. In some mysterious way, this magnetic force creates two opposite magnetic poles. Its north pole attracts the south pole of another magnet. Opposites attract each other. Two south poles repel each other, so do two north poles.
It is not necessary to line all of their electron breezes in the same direction. Actually they are arranged in magnetic centers called domains, each of which has a team of perhaps a thousand million atoms whose electron breezes blow in the same direction. If an iron bar has enough of these domains, their combined force makes it into a magnet.