Exploring MagnetsIntroduction
Long, long ago — so the story goes — a shepherd named Magnes lived in a Greek town. One day, while walking with his iron-tipped staff and iron-fitted sandals, he found his feet strangely stuck to the ground on a particular hillside. The hill was made of a rock that pulled iron towards itself!
That rock was lodestone, a natural magnet — and it gave us both the words magnet and magnetism. Whether or not the legend is true, people have been fascinated by this invisible force ever since.
In this chapter we will explore what magnets attract, why every magnet has two poles, how a compass uses a magnet to find directions, and the fun tricks magnets make possible. The book uses hands-on activities — here you can do the same explorations virtually.
Magnetic and Non-magnetic Materials
Let's start with the book's very first activity. Collect a few objects from around you: an iron nail, a steel pin, a plastic ruler, a pencil, a copper wire, a piece of chalk, an eraser and an aluminium foil. Bring a magnet close to each one. Which objects stick to the magnet?
Sort the materials
Drag each object onto the magnet to test it — or away from it to leave it untested!
Magnetic: 0 · Non-magnetic: 0
Materials that are attracted by a magnet — like iron, nickel and cobalt — are called
Notice one surprising case: while iron sticks strongly, a steel spoon is magnetic too — because steel is mostly iron! But a copper coin or an aluminium foil is not, even though they are metals. Not all metals are magnetic.
Do you know?
Magnets are used in everyday life: refrigerator doors, pencil boxes with magnetic lids, pin holders on notice boards, smartphone cases, and electric bells. A smartphone even contains a tiny magnetic sensor that detects the Earth's magnetic field — more on that below!
Poles of a Magnet
Sprinkle some iron filings around a bar magnet (or drag the virtual filings below) and watch where they stick:
The iron filings cluster most thickly at the
Every magnet — whatever its shape — always has two poles:
North pole
The end of a freely-suspended magnet that points towards the
South pole
The end that points towards the south is the south-seeking pole, or the South pole (S).
COMING SOON: freely-suspended magnet animation
Attraction and Repulsion
What happens when you bring two magnets close to each other? Try it:
Find out
The ends of two suspended magnets are brought together in different combinations. Predict, then verify:
| Ends brought together | Attract or repel? |
|---|---|
| N – N | |
| N – S | |
| S – N | |
| S – S |
The rule is simple:
Like poles repel each other; unlike poles attract each other.
Move the slider to bring the two magnets closer. Watch how the top pair (unlike poles) pulls together, while the bottom pair (like poles) pushes apart. This is exactly what you will observe with real magnets in Activity 4.5 of the book.
Finding Directions
A freely suspended magnet always comes to rest in the north–south direction. Sailors and travellers have used this property for over a thousand years: the magnetic compass.
A compass has a small magnetised needle that can rotate freely. Try it:
Compass explorer
Rotate the world around the needle:
Wherever you turn the compass case, the needle always settles along the
The needle's red end points towards the Earth's geographic north and the blue end towards the south. This is because the Earth itself behaves like a giant magnet!
That is also how a smartphone compass works: the phone contains a tiny magnetic sensor that measures the Earth's magnetic field and displays the direction — a lovely example of "Thinking with AI" from your book.
Fun with Magnets
Magnets lose their properties if they are heated, hammered or dropped from a height. They also become weak if not stored properly — that's why bar magnets are stored in pairs with keepers, and compass needles are protected.
Quick quiz — test yourself
- A magnet attracts iron, nickel and cobalt, but not copper or aluminium.
- A magnet has
poles. - Like poles
each other. - A freely suspended magnet settles along the
direction. - Which of these is NOT magnetic?
Wonderful! You can now explain why a compass works, why magnets stick to fridge doors, and why dropping your magnets is a bad idea. Next stop: measuring the world with rulers and understanding motion — in the Measurement of Length and Motion course!
Chapter Summary
- Magnetic materials — iron, nickel, cobalt (and their alloys like steel) — are attracted to magnets; most other materials are non-magnetic.
- Every magnet has two poles, north (N) and south (S). The magnet's attraction is strongest at the poles.
- Like poles repel; unlike poles attract.
- A freely suspended magnet always aligns along the north–south direction — the working principle of the magnetic compass.
- The Earth itself behaves like a giant magnet.
- Magnets lose their magnetism when heated, hammered or dropped.
Magnets are everywhere: fridge doors, pencil boxes, speakers, electric bells, and even inside your smartphone's compass sensor.