Navigating with Magnetism
Introduction
Scouts are resourceful and love a good adventure! If you ever find yourself lost in the bush without a compass, you can make your own using simple materials. This activity explores the Earth’s magnetic field, teaching Scouts how to magnetise a needle and create a working compass.
Through this experiment, Scouts will also learn about ferromagnetism, polarity, and navigation, and test different factors that affect a compass’s accuracy.
What you'll need
- A strong magnet (the stronger, the better)
- An iron sewing needle (must be ferromagnetic)
- A leaf or a small piece of cork (something that floats)
- A shallow plastic or ceramic bowl (avoid metal bowls)
- Water
- A real compass (optional) to compare accuracy
Before you begin
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Discuss with the Unit:
- What is a compass and how does it work?
- What makes Earth’s magnetic field important for navigation?
- How do magnets interact with different materials?
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Ensure you have a safe, open area away from strong electromagnetic sources (e.g. powerlines, metal buildings)
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Check your materials – Not all needles are magnetic (some are made of aluminium or copper and won’t work)
Activity
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Prepare the Floating Base:
- Fill a shallow bowl with about 3cm of water
- Place the leaf or cork in the middle so it floats freely
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Magnetise the Needle:
- Take a strong magnet and stroke the needle in one direction along the bar magnet about 30 times
- Always use the same end of the magnet and stroke the needle in the same direction
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Create Your Compass:
- Carefully place the magnetised needle onto the floating leaf or cork
- Observe what happens—the needle should align with Earth’s magnetic field and point north-south
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Determine True North:
- Use the sun or stars to determine which direction is actually north
- Remember: The Sun rises in the east and sets in the west!
Change the challenge level
Easier:
- Use a pre-magnetised needle
- Skip the experiment and focus on observing how a real compass works
- Place the needle through the cork horizontally to keep it balanced
Harder:
- Test different types of needles or metals (e.g. aluminium, copper, zinc) – do they work?
- Experiment with different strengths of magnets – how does it affect the needle’s movement?
- Try different floating materials (dry vs. wet leaves, cork, plastic, paper)
- Place the compass near metal objects or electrical devices – does this change the results?
Reflection
- Did the needle align with Earth’s magnetic field as expected?
- How did the number of strokes on the magnet affect the results?
- What happened when different materials were used?
- If Scouts were lost in the bush, how could they use this skill for navigation?
- What are some real-world uses of magnetism in science and technology?