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Class 6 Science • Chapter 13

Fun with Magnets

Vardaan Learning Institute • Detailed Chapter Notes

🧲 1. What is a Magnet?

A magnet is a material that can attract certain metals (mainly iron, cobalt, nickel) towards it. The word "magnet" comes from Magnesia, a place in ancient Greece where a special black rock was found that could attract pieces of iron. This rock was called magnetite or lodestone (Fe₃O₄).

Magnetic Materials = materials attracted by a magnet: Iron, Cobalt, Nickel (and their alloys like steel)
Non-magnetic materials = NOT attracted by a magnet: Plastic, wood, paper, glass, rubber, aluminium, copper, gold, silver
Note: All materials attracted by a magnet are metals but NOT all metals are magnetic! (Aluminium, copper, gold are metals but non-magnetic)

🏔️ 2. Types of Magnets and Their Shapes

Type Shape Use
Bar Magnet Rectangular bar/stick shape Science labs, door latches
Horseshoe Magnet U-shape (like a horseshoe) More powerful — both poles face same direction; used in motor repair, holding
Disc/Ring Magnet Round, flat disc shape Loudspeakers, microphones
Cylindrical Magnet Cylindrical rod Fridge magnets, small devices
Electromagnet Coil of wire around iron core Electric bells, cranes, MRI machines, speakers
📸 Image Prompt
A neat educational diagram showing 4 common magnet shapes side by side on white background: (1) Bar magnet — rectangular stick with one end labeled N (red) and other end labeled S (blue), (2) Horseshoe magnet — U-shaped with N and S at the open ends both facing the same direction, (3) Disc/ring magnet — round flat disc with N and S on top and bottom faces, (4) Cylindrical magnet — thick rod shape with N and S at the two ends. Each shape labeled with its name below it. Clear colors: red for N pole, blue for S pole. Simple educational illustration style.
Fig. 13.1 — Types of magnets and their shapes

🔴🔵 3. Poles of a Magnet

Every magnet has two ends called poles — the North Pole (N) and the South Pole (S). The magnetic force is strongest at the poles.

🧲 Law of Magnetic Poles: Think: "Opposites attract, but similarities repel!"
📸 Image Prompt
Two-panel illustration: Left panel labeled "Like Poles Repel" — two bar magnets facing each other with N facing N, showing bold curved red repulsion arrows pushing them apart. Right panel labeled "Unlike Poles Attract" — two bar magnets facing each other with N facing S, showing bold green attraction arrows pulling them toward each other. Both panels have the magnets labeled with N and S poles in red and blue. Clean white background, educational style.
Fig. 13.2 — Attraction and repulsion between magnetic poles

🧭 4. The Magnetic Compass — A Magnet as a Direction Finder!

A magnetic compass is a device that uses a freely pivoting magnetized needle to show direction. The needle always aligns itself in the North-South direction because the Earth itself acts as a huge magnet!

Why does a suspended magnet always point North-South?
The Earth has a magnetic field — it acts like a giant bar magnet. The North Pole of the compass needle gets attracted to the Earth's geographic North (which has a magnetic South pole in Earth's interior), so it always points toward Geographic North.

Old name for compass needle: The freely floating/pivoting magnetic needle was called a "disha-soochi" in ancient India (literally "direction needle"). Chinese sailors used magnetized needles floating in water for navigation more than 1000 years ago!

🔨 5. Making a Magnet and Demagnetization

Ways to Make a Magnet:

  1. Single Touch Method: Stroke a magnetic material (iron bar) with one pole of a permanent magnet repeatedly in the SAME direction. After many strokes, the iron bar becomes magnetized.
  2. Double Touch Method: Two magnets (N and S poles) are placed in the middle of the iron bar and stroked outwards simultaneously in opposite directions to the ends.
  3. Electrical Method: Wrap insulated copper wire around an iron bar and pass electric current through it → creates an electromagnet

How to Demagnetize (Remove Magnetism):

A magnet can lose its magnetism if: That's why magnets should be stored with their like poles facing each other (using keeper bars) and not dropped or hammered.

📊 6. Properties of Magnets — Summary

Property Detail
Attraction Attracts iron, cobalt, nickel (magnetic materials)
Poles Every magnet has 2 poles: North (N) and South (S). Poles cannot be separated — if a magnet is cut, each piece becomes a new magnet with N and S!
Like poles Repel each other (N–N, S–S)
Unlike poles Attract each other (N–S)
Directionality A freely hanging magnet always points North-South
Magnetic field The region around a magnet where another magnet/magnetic material feels force
🎯 What happens when you cut a magnet in half? If you cut a bar magnet in half, you do NOT get a separate N pole and S pole — you get two smaller magnets, each with their own N and S pole! You can NEVER isolate a single magnetic pole (magnetic monopole).

🌍 7. Earth as a Magnet

📝 8. Quick Revision

  1. Magnet attracts iron, cobalt, nickel. NOT attracted: aluminium, copper, plastic, wood
  2. Original natural magnet = Magnetite/Lodestone
  3. Every magnet has N pole and S pole. Like poles repel; unlike poles attract
  4. A magnet suspended freely always points North-South → this is how compass works
  5. Earth = big magnet; geographic North = magnetic South (inside Earth)
  6. Magnet cut in half → two new magnets (each with N and S) — cannot isolate single pole
  7. Magnets lose magnetism by: heating, hammering, rough handling
  8. Electromagnet = current through coil around iron core → temporary magnet