Exploring Magnets

Class 6 Science - Chapter 4: Discover the fascinating world of magnets, magnetic materials, poles, and how compasses work.

A stormy, overcast night at sea… no stars to guide the sailors.
What else can show direction? → A magnetic compass!

🧲 Big Ideas & Story Hook

In olden days, travellers used a magnetic compass to find directions when stars weren't visible.
Magnets appear in daily life: pencil-box closures, purses, dusters on boards, toy parts.
Natural magnets: lodestone (ancient). Today we also have artificial magnets in many shapes.
Why this matters: magnets help in navigation, holding/closing, sorting metals, toys, and science tools.

🧲 Magnetic vs Non-magnetic Materials

Magnetic Materials

Iron (Fe)

Nails, paperclips, steel objects

Nickel (Ni)

Some coins, alloys

Cobalt (Co)

Some magnets, alloys

Non-magnetic Materials

Wood

Tables, chairs, pencils

Plastic

Bottles, toys, containers

Glass

Windows, bottles, mirrors

Rubber

Erasers, tires, bands

Most stones

Rocks, pebbles, gems

💡 Memory Trick:

"INC are IN the magnetic club" → Iron, Nickel, Cobalt.

🔧 Shapes of Magnets

Bar Magnet

Rectangular with N and S poles at ends

General purpose, experiments

U/Horse-shoe Magnet

U-shaped with poles at tips

Stronger field, lifting objects

Ring Magnet

Circular with poles on opposite sides

Motors, generators

Disc Magnet

Flat circular with poles on faces

Small devices, crafts

🧭 Poles of a Magnet

Key Points:

Ends are poles: North (N) and South (S)
Magnetism is strongest near the poles
No single pole exists: breaking a magnet gives smaller magnets, each with both N and S

Misconception Fix:

You cannot get an isolated N or S by cutting a magnet.

🧭 Make Your Own Compass

You'll need:

Sewing needle, bar magnet, cork, bowl of water

Lay needle on table; stroke it 30–40 times with the same pole of the bar magnet in one direction

Pass needle through a cork; float on water so needle stays above water

When it stops turning, note direction → your compass!

History Nugget:

A floating, magnetised fish-shaped iron (matsya-yantra) in oil was once used for navigation in India.

⚡ When Two Magnets Meet: Attraction vs Repulsion

Attraction

Unlike poles attract (N–S)

↔️

Repulsion

Like poles repel (N–N or S–S)

↔️

Sure Test of a Magnet:

Repulsion (only a magnet can repel a magnet; an unmagnetised iron bar will be attracted by either pole).

🧪 Mini-Labs & Observations

Concept	Setup	What to See	What it Proves
Poles strongest	Iron filings + bar magnet	Filings cluster at ends	Poles are strongest
Direction finder	Suspend magnet by thread	Settles N–S	Earth is like a magnet
Make a compass	Magnetise needle, float on cork	Needle aligns N–S	Needle became a magnet
Repulsion test	Two bar magnets	N–N or S–S push away	Like poles repel (sure test)
Through materials	Compass + magnet + wood/plastic/glass between	Needle still deflects	Field passes through non-magnetic sheets

🎮 Fun with Magnets (STEM corners)

Magnetic Garland

Ring magnets stick into a chain

Maze Game

Move steel balls in a maze with a magnet beneath the board

Paperclip-in-water Rescue

Lift it using a magnet outside the cup (no wet fingers!)

Matchbox-magnet Cars

Face like poles to repel and 'drive' them apart

Ring-magnet Hover

Stack rings with like poles facing to keep a gap

🧠 Memory Boosters

INC

Iron, Nickel, Cobalt are magnetic

No Single

No single pole exists; poles come in pairs

AR rule

Attract (unlike), Repel (like)

R = Real test

Repulsion is the real/sure test for identifying a magnet

🛡️ Caring for Magnets (Do's & Don'ts)

❌ Don'ts

• Do not heat magnets
• Do not drop or hammer magnets
• Keep away from mobiles/remotes

✅ Do's

• Keep unlike poles together
• Use wooden spacer between magnets
• Use soft iron keepers across ends

Reason:

Protects magnetic strength and prevents self-demagnetisation.

📚 HOTS / Exam-Style Practice

1. You have 3 identical metal bars; 2 are magnets, 1 is ordinary iron. No other tools. How do you identify the magnets? (Hint: look for repulsion.)

2. A bar magnet has no pole markings. How can you find which end is North without another magnet? (Hint: suspend it freely; the North-seeking end points North.)

3. Why is repulsion considered a sure test for magnetism, but attraction is not?

4. A compass shows N–S even with a plastic sheet in between. What does that tell you about magnetic influence?

5. In a 'matchbox-magnet car' race, cars rush apart when brought close. Explain using poles.

🎯 Quick Recap

Key Points:

• Only some materials (mostly iron, nickel, cobalt) are magnetic
• A magnet has two poles; no single pole is possible
• A free magnet aligns North–South; compasses use this to show direction
• Unlike attract, like repel; repulsion is the sure test for a magnet
• Magnetic influence can act through many non-magnetic materials
• Handle & store magnets carefully to retain strength

Memory Tricks:

• INC → Iron, Nickel, Cobalt are magnetic
• No Single → No single pole exists; poles come in pairs
• AR rule → Attract (unlike), Repel (like)
• R = Real test → Repulsion is the real/sure test for identifying a magnet

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