Magnets & Magnetism
Year 7 ⚡ Electricity & Magnetism Describe magnetic poles, fields and uses of magnets; compasses.
🧲 Magnetic Poles
Every magnet has two poles: a north pole (N) and a south pole (S). The rules for attraction and repulsion are simple!
🧲 Magnetic Poles Rule
$$\text{Unlike poles ATTRACT} \quad (N \leftrightarrow S)$$
$$\text{Like poles REPEL} \quad (N \leftrightarrow N \text{ or } S \leftrightarrow S)$$ You can NEVER separate a magnet into just one pole — if you cut a magnet in half, you get TWO smaller magnets, each with N and S poles!
| 🔬 Material | 🧲 Magnetic? |
|---|---|
| Iron, steel, nickel, cobalt | ✅ Yes (ferromagnetic) |
| Copper, aluminium, plastic, wood | ❌ No |
🗺️ Magnetic Fields
A magnetic field is the region around a magnet where magnetic forces act. We draw magnetic field lines to show the direction and strength.
| 📝 Rule | 📖 What it means |
|---|---|
| Direction | Field lines go from North to South outside the magnet |
| Strength | Closer lines = stronger field (near the poles) |
| Never cross | Field lines never intersect |
🌍 Earth's magnetic field: Earth acts like a giant bar magnet — a compass needle's north pole points toward geographic North, because Earth's geographic North Pole is actually a magnetic south pole!
⚙️ Uses of Magnets
Magnets are incredibly useful in modern technology!
| ⚙️ Use | 📖 How magnets help |
|---|---|
| 🧭 Compass | Needle aligns with Earth's magnetic field |
| 💳 Credit/debit cards | Magnetic strip stores account data |
| ⚡ Electric motors | Magnetic forces spin the motor |
| 🏥 MRI scanner | Strong magnets create body images |
| 🔊 Loudspeakers | Electromagnet vibrates to produce sound |
| 🚂 Maglev trains | Magnetic repulsion lifts the train! |
Keep magnets away from credit cards, computers and pacemakers — magnetic fields can damage them!
Ready to test yourself? Click the Quiz tab above to answer questions on this topic!
🧲 Magnetic Field Explorer
Explore magnetic field concepts and materials.