Integrated Science — Force and Energy

Subtopic: Magnetism (Age 12 / Kenyan context)

Magnetism is a force made by magnets. It can pull (attract) or push (repel) certain materials without touching them. We feel magnetism in many everyday objects and tools in Kenya — for example, compasses used by scouts and fishermen, loudspeakers in radios, and electric motors in fans and food grinders.

What is a magnet?

• A magnet is anything that produces a magnetic field.
• It has two ends called poles: a North (N) pole and a South (S) pole.
• Opposite poles attract (N to S). Like poles repel (N to N or S to S).

Types of magnets

• Natural magnet (e.g., lodestone).
• Bar magnet (hard or soft steel shaped like a bar).
• Horse-shoe magnet (U-shaped to make poles close and strong).
• Electromagnet: created by an electric current in a coil of wire around an iron core. Turn off the current → magnetism stops.

Everyday uses (Kenyan examples)

• Compasses for navigation during hiking or by fishermen.
• Speakers and radios — magnets help turn electric signals into sound.
• Electric motors in fans, blenders, and pumps.
• Magnetic separation in small-scale farming to remove metal pieces from grain or flour (industrial use).

Simple class experiments and demonstrations

1. Attracting paper clips:
   • Use a bar magnet to pick up paper clips. Count how many it picks. That shows magnet strength.
2. Make a simple compass:
   • Straighten a sewing needle, stroke it 20 times in one direction with a magnet (magnetize it).
   • Float the needle on a small piece of cork in a bowl of water. The needle points toward magnetic north.
3. Magnetise and demagnetise:
   • Stroke a steel nail with a bar magnet to magnetize it. Test with paper clips.
   • To demagnetize, heat the nail (with care and teacher supervision) or hit it and test again.
4. Build a simple electromagnet:
   • Wrap many turns of insulated copper wire around an iron nail. Connect to a small battery (teacher help needed).
   • The nail becomes a magnet when current flows. Disconnect battery → magnetism stops.

Safety and care

• Do not swallow magnets. Keep small magnets away from young children.
• Keep strong magnets away from mobile phones, credit cards and other electronic devices — magnets can damage them.
• When using batteries and wires, work with teacher supervision to avoid short circuits and burns.

Summary — Key points to remember

• Magnets have two poles: North and South.
• Opposite poles attract; like poles repel.
• Magnetic materials include iron, nickel, and cobalt.
• Earth behaves like a giant magnet, which is why compasses point north.
• Electromagnets work only when electricity flows through them.

Short quiz (try these)

1. What are the two poles of a magnet called?
2. What happens when two north poles are brought together?
3. Name two magnetic materials.
4. Give one use of a magnet in daily life in Kenya.
5. What makes an electromagnet stop being magnetic?

Note for teachers: experiments that use electricity or heat must be done under supervision. Encourage learners to make observations and draw simple diagrams in their notebooks.