Magnetism
Primary 6 · Science and Elementary Technology
Magnetism
Lesson 6 of 6
15 min
Let's begin
On a school hiking trip in Nyungwe Forest, the path splits in two. Thick clouds hide the sun, and nobody can tell which way is north.
The guide smiles and takes a small round object from her pocket. A thin needle inside swings, trembles and settles. "Our camp is to the east," she says. "This way!"
A compass has a small, light magnetised needle that turns freely on a pin, inside a case marked with the directions North (N), East (E), South (S) and West (W). Because the Earth is a giant magnet, the needle lines up with the Earth's magnetic field, and its north pole points north.
To use a compass: hold it flat, wait for the needle to stop, then turn the case until the letter N lines up with the needle. Now you can read every direction. Keep the compass away from magnets, iron objects and phones, because they pull the needle and give a wrong reading.
Tip
Where is the magnet hiding?
If something sticks shut, makes sound, spins with electricity or points north, there is probably a magnet inside.
Try each one on your own first, then tap Show answer to check.
Why does a compass needle point north?
Answer: The needle is a small magnet, and it lines up with the Earth's magnetic field.
Name three uses of magnets in the home.
Answer: Any three: fridge door seal, fridge magnets, cupboard catches, loudspeakers, radio, electric fan motor, bag clasps.
How does a scrap-yard crane drop the iron it has lifted?
Answer: It uses an electromagnet; the operator switches off the current, so the magnet stops working and the iron falls.
Why should you keep a compass away from a magnet?
Answer: The magnet pulls the needle, so the compass points the wrong way.
What do you need to make a floating compass?
Answer: A magnetised steel needle, a piece of cork (or a leaf or bottle top), and a bowl of still water.
What you learned today
Sources and credits
Quick check
Put the steps for using a compass in order.
Tap the cards in the right order.
