EXPERIMENT 47
EXPERIMENT 46
WHAT’S HAPPENING
Now the needle really does act
like a magnet, even if only a
weak one.
The needle is made of steel,
which is a kind of iron that has
been treated in a special way.
When you magnetize steel, it
retains its magnetic power.
46
WHAT’S HAPPENING
Whether you’re inside or
outside, the magnet always
points in the same direction.
TIP!
Be sure to keep the
magnetic needle in a safe
place, since you’ll be
needing it for other
experiments.
Mysterious behavior
HERE’S HOW
Place the hanger device, with the bar magnet sus-
pended from it, in various locations around your
home. Wait each time for the magnet to stop moving.
Watch carefully. Do you notice anything?
Look for a notable landmark some distance away
(say, a tall building or a mountain) in the direction in
which the magnet is pointing. Also try going outside
to see what direction the magnet points.
Researchers tend to have excellent powers of observation. Are you a good observer?
Let’s find out!
Birth of a magnet
HERE’S HOW
Start by using the iron pieces to test the
needle for magnetism. It will presumably
be very weak at best.
Now stroke the blue pole of the bar mag-
net 50 to 100 times across the needle,
always in the same direction.
Test the needle again. What do you find?
In Experiment 32 (Contagious magnetism), you saw how a piece of iron can turn
into a magnet when it is touched by a magnet. Unfortunately, the magnetic
power disappears as soon as the iron and the magnet are separated. But that
isn’t true for all iron objects.
Содержание Electricity and Magnetism 620417
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