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Lesson 2 Summary
Use with pp. 48–53
Lesson 2: What are magnetic effects?
Compasses and the World’s
Largest Magnet
The needle on a compass always moves
so that one end points north and one end
points south. Why? A compass needle
points north because the Earth is like a
large magnet.
No one knows exactly why Earth is like
a magnet. Scientists think that deep inside
the Earth, there is a layer called the outer
core. The outer core is made of very hot,
melted iron. The Earth rotates, or spins.
This makes electric currents flow in the
liquid iron. The current makes a magnetic
field.
Magnetic Minerals
Some rocks and minerals are magnets.
For example, magnetite is a mineral
that is magnetic. Magnetite is also called
lodestone. Hundreds of years ago, sailors
used lodestones as compasses. Lodestone
points north the same way that a compass
needle points north.
Earth’s Magnetic Poles
Earth’s magnetic field is strongest at the
magnetic poles. But the magnetic poles are
not the same as the poles on a map or on
a globe. The poles on a map are called the
geographic poles. The magnetic north pole
is in Canada. It is about 1,000 kilometers
(600 miles) away from the geographic
North Pole. The magnetic south pole is in
the ocean near Antarctica.
What happens if you put a magnet or
a magnetite rock near a compass? The
magnetic field of the magnet is stronger
than the magnetic field of the Earth. The
compass needle moves toward the magnet.
The compass needle does not point to the
north.
Earth’s Magnetic Field
Any magnet can act like a compass. You
just have to hang a magnet so that it turns
or moves easily. The magnet will turn so
that one end points north and the other
end points south.
How to Make a Compass
You can make a compass. Use a needle,
a magnet, a bowl of water, and a sponge or
piece of cork.
First, rub the needle on the magnet.
Move the needle quickly. Always move the
needle in the same direction. The needle
gets a magnetic field. Then put the needle
on top of the piece of sponge or cork. Put
the sponge or cork on top of the water. The
needle will line up with Earth’s magnetic
field.
Finding Your Way
The directions north, south, east, and
west are labeled on a compass. Turn the
compass so that the needle points to the
“north” label.
© Pearson Education, Inc. 4
Compasses
A compass needle is a tiny, lightweight
magnet. The needle is attached inside the
compass so that it can turn and spin easily.
One end of a compass needle always points
to the magnetic north pole. The compass
needle lines up with Earth’s magnetic field.
10 Chapter 2, Lesson 2 Summary
Intervention Study Guide
Name ______________________________
Lesson 2 Questions
Use with pp. 48–53
Lesson 2 Questions
1. In the Lesson 2 Summary, find one example of a mineral that is
magnetic. Underline the name of the mineral.
2. Where is the Earth’s magnetic field strongest?
© Pearson Education, Inc. 4
3. Imagine that you put a magnet near a compass. What does the
compass needle do?
Intervention Study Guide
Chapter 2, Lesson 2 Questions 11