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Only a few materials are strongly magnetic: iron, nickel and cobalt (and a rare metal called gadolinium). Steel, which is mostly iron, is magnetic too. Most other materials, such as plastic, wood, copper and aluminium, are not.

Every magnet has a north pole and a south pole. Like poles repel (push apart) and unlike poles attract (pull together). If you cut a magnet in half, you do not get a separate north and south: you get two smaller magnets, each with both poles.

The Earth acts like a giant bar magnet. A compass needle is a small magnet that lines up with Earth's magnetism, so its north end points north. Most of Earth's magnetism is made deep inside the planet, where liquid iron and nickel churn in the outer core.

Experiment: Build an electromagnet

1. Leave about 20 cm of wire free, then wrap 10 turns of wire tightly around the nail. Strip the insulation from the wire ends (an adult helps).
2. Tape the wire ends to the two ends of the battery for a few seconds only.
3. While connected, touch the nail tip to the paper clips. Count how many it picks up.
4. Disconnect. What happens to the paper clips?
5. Now wrap 20 turns, then 30 turns, and count the paper clips each time. Keep the battery the same.

Turns of wire	Paper clips lifted (try 1)	Paper clips lifted (try 2)
10
20
30

Questions

1. Name three magnetic metals.

2. Explain why a compass needle points north.

3. How did the number of turns change your electromagnet? Why?

4. Why are we lucky that Earth has a magnetosphere?

Sources for every fact on this sheet: echoesof.science/school/magnetism/sources/

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