The document discusses the aurora borealis and australis, which are light effects caused by cosmic rays interacting with gases in the Earth's atmosphere at the magnetic poles. It also describes how compasses work, noting that the compass needle points towards magnetic north and was an important tool for medieval trade and exploration. Finally, it provides some review questions about magnets, the Earth's magnetic field, where compasses point, and the usefulness of compasses.

2. Electricity and
Magnetism Part 3

3. Aurora Borealis and
AuroraAustralis

4. Did you know?
 The Earth´s magnet field protects our planet from
cosmic rays.
 However, some of them enter the Earth´s
atmosphere at the magnetic poles.
 They combine with the gases in the atmosphere to
produce incredible light effects.
 These are called the Aurora Borealis in the
Northern Hemisphere and the Aurora Australis in
the Southern Hemisphere.

5. Compass
 A compass is a navigational instrument. The
needle in the compass is magnetised and
points to the magnetic North Pole.The circle
around the needle, also called a rose, is
marked with the cardinal points, north,
south, east, and west, and the degrees in
between. Using a map and a compass, you
can find your way in unknown terrain, even if
visibility is poor.
 Compasses were first used in medieval times
and the invention of the dry compass which
could be taken aboard ships meant that trade
and exploration flourished in this period.

6. Check out 1
(Notebook)
 Explain the differences between permanent
magnets and induced magnets
 Write two sentences about magnets using
the key words
 a. magnet/poles b. attract/repel
 How can we see the magnetic field around a
magnet?

7. Check out 2
How does the Earth´s magnetic field
protect us?
Where do compasses point towards?
Choose the correct answer.
a. North Pole b the Sun c the South
Pole d magnetic North Pole
Why are compasses useful? Why were
they important in the past?