That is a very good question, and in fact the
answer is very complicated!
First you might
want to try an experiment:
Take a magnet
(a refrigerator magnet will work fine) and try
attaching it to all of the metal objects in your
house (be careful you don't scratch your parents'
car while you're doing this!)
What do you
You should find that in fact it
doesn't attach to all of the metal objects, only
to some of them. If you know a little bit about
metals, you might notice that most of the metals
that stick to the magnet are made of steel. Steel
is what we call an ALLOY, a fancy word which just
means that it contains a few different things
mixed together, but it's mostly made up of
So why does iron stick to a
Well, first we have to think a
little bit about how magnets work, and this is
where it gets a bit complicated. We can think of a
magnet as having a"north pole" at one end, and a
"south pole" at the other end. (The names come
from the fact that the Earth is in fact a magnet,
with the "ends" of the earth's magnet at the north
and south poles!) Whenever a magnet's North Pole
comes across the south pole of another magnet it
sticks to it. Whereas if a north pole comes across
another north pole it pushes it away.
can try this if you have 2 bar magnets; they stick
to each other strongly in one direction, but not
in the other.
Next you have to believe me
that iron is actually made up of billions of tiny
little magnets! Each one is just like the needle
of a compass, but much smaller. (If you've heard
about atoms, you can think of each atom as being a
Now let's do a "thought
experiment" (scientists use this lot to try to
figure out what might happen before they go into
the lab and do a real experiment). Let's imagine
that we have a piece of iron, and we bring the
north pole of a big magnet close to the top of it.
(You might want to try sketching a picture of this
as you're thinking through it; scientists do that
a lot too!) Well, we know that the north pole of a
magnet will push away any other north poles it
comes close to. So each of the tiny magnets in the
iron will turn itself round (just like a compass
needle) so that its north pole is as far as
possible from the north pole of the big magnet. Of
course this means that the south poles of the tiny
magnets lineup close to the north pole of the big
magnet. And we know that south poles stick to
north poles! So the iron sticks to the big magnet!
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