Exploring Magnets
(चुम्बकों को जानें / चुंबकाची गंमत)
Investigate magnetic poles, navigate with compass needles, test magnetic attraction versus repulsion, and explore Earth’s hidden geomagnetic core!
PhET Magnet & Compass Simulator
👉 Things to try: Drag the Compass around the bar magnet to see how the needle turns. Turn on “See Inside” to observe atomic magnetic domains, and click “Earth” mode to reveal why our planet is a giant bar magnet!
Simulation licensed under CC BY-NC 4.0 (PhET Interactive Simulations, University of Colorado Boulder).
The Magnetic Sorter Challenge
Test which everyday items stick to a magnet and which are non-magnetic!
Drop materials that are pulled toward a magnet (Iron, Nickel, Cobalt, Steel).
Drop materials that feel zero attraction (Wood, Glass, Copper, Plastic).
Magnetism Master Mind Map
1. Types & Origins
• Natural Magnet: Magnetite (Lodestone, $Fe_3O_4$). Discovered in Magnesia, Greece.
• Artificial Magnets: Bar, Horseshoe, Cylindrical, Ring, and Needle magnets made by humans.
2. Magnetic Poles
• Two Poles: North (N) and South (S).
• Max Attraction: Magnetic force is concentrated at the poles, weakest in the center.
• Poles Always in Pairs: Breaking a magnet in half produces two smaller complete magnets!
3. Finding Direction
• Directive Property: A freely suspended magnet always settles in North-South direction.
• Magnetic Compass: Ancient Chinese mariners used magnetized needles for navigation.
• Earth as a Magnet: Earth has internal magnetic poles.
4. Laws & Care
• Law of Poles: Like poles repel (N-N, S-S); unlike poles attract (N-S).
• Sure Test: Repulsion is the only definitive test of magnetism.
• Demagnetization: Magnets lose power if heated, hammered, or dropped.
Micro-Topic Study Guide
1. Story of Discovery: Magnes & Lodestone
Legend says a Greek shepherd named Magnes was herding sheep on Mount Ida. The iron tip of his walking stick and the iron nails in his sandals became stuck to a black rock! That naturally magnetic rock was named Magnetite (named after Magnesia in Greece, or Magnes the shepherd). Because it could guide lost travellers, it was also called Lodestone (meaning “leading stone”).
2. Magnetic vs. Non-Magnetic Materials
Materials attracted by a magnet. Only 3 pure elemental metals are ferromagnetic at room temperature: • Iron (and Steel) • Nickel • Cobalt
Materials completely indifferent to a magnet. • Wood, Plastic, Glass, Rubber, Paper, and Non-ferrous metals (Copper, Aluminium, Gold, Silver).
3. Why Repulsion is the Sure Test of Magnetism
If you bring an unknown object near the North pole of a bar magnet and it attracts:
• It could be another magnet’s South pole, OR it could just be an unmagnetized piece of ordinary iron!
However, if the object is repelled, it must be a magnet carrying an identical North pole, because ordinary iron never repels. Hence, repulsion is the only foolproof test of magnetism.
4. How to Make Your Own Magnet (Single-Touch Method)
- Take an unmagnetized steel sewing needle or iron strip and lay it flat on a wooden table.
- Take a bar magnet, hold one of its poles (e.g. North pole) at one end of the needle.
- Without lifting, drag the magnet along the length of the needle to the opposite end.
- Lift the magnet high, return to the starting point, and repeat the stroke in the same direction 30–40 times.
- Bring iron pins near the needle — it has now transformed into a temporary magnet!
5. Proper Storage & Magnetic Keepers
Magnets lose their strength over time if left unprotected (self-demagnetization).
• Storage Rule: Store bar magnets in pairs with unlike poles side-by-side. Place a piece of wood between them and place two strips of soft iron (called Magnetic Keepers) across both ends to close the magnetic field loop.
• Never heat a magnet over a flame, strike it with a hammer, or drop it on hard flooring!
25-Question Chapter Mastery Quiz
Instant evaluation, score counter, and scientific explanations for every question: