How do magnets
Magnetism is a force created by electricity. When a
thing has more electrons than it has protons, it has a negative charge.
If it has more protons than electrons, it has a positive charge. If you
put two things with negative charges near each other, they push apart
from each other, and so do two things with positive charges. A
positively charged thing will pull toward a negatively charged thing. We
call this pulling and pushing, “magnetism.”
Small iron rocks on the surface of the Earth are
also sometimes naturally magnetic. Inside these iron oxide rocks, called
lodestones, are iron atoms that are tiny magnets that have electrons
moving around and around in a circle that sets up a magnetic field. In
ordinary iron, the atoms are jumbled up so that they all pull in
different directions. In a lodestone the iron atoms have gotten lined up
so that most of them pull in the same direction, making the lodestone
into a big magnet.
Magnets are usually made of metal iron or another
material that has a lot of iron in it. Magnets cans be in many shapes
and sizes, but all of them have the ability to pull things toward
themselves. Magnets only attract or pull metals that are made of iron or
Magnetism is concentrated around the poles, or
ends, of a magnet. A magnet has a north pole and a south pole. The two
poles may look the same, but they behave differently from each other. If
you put one pole of a magnet near the pole of another magnet, you may
feel an attraction (pulling) force as the two poles stick together, or
you may feel a repulsion (pushing) force, as the two poles push away
from each other. It has been shown by experiments that like poles repel
each other, and unlike poles attract each other.
The space surrounding a magnet where the magnetic
force is exerted is called a magnetic field. If a magnet is placed in
such a field, it will experience magnetic forces. The field will
continue to exist even if the magnet is removed. In many ways, our Earth
is like a big magnet. Lines of magnetic force run through the planet.
And, just like a magnet, Earth has a north pole and a south pole.
When current flows in a wire, a magnetic field is
created around the wire. From this it has been shown that magnetic
fields are produced by the motion of electrical charges. A magnetic
field of a magnet results from the motion of negatively charged
electrons in the magnet.
You cannot see the magnetic force around a magnet,
but you can see the effects of its presence when an iron nail sticks to
a magnet. You can see the shape of a magnetic field by using tiny,
powder-like pieces of iron, called iron filings, which reveal that the
lines and strength of the magnetic force are concentrated around and
between the poles at the end of the horseshoe magnet. On a bar magnet,
they line up to show how the magnetic force spreads out from the poles.