Magnetic and Non-magnetic Materials

1Magnetic materials

Materials that are attracted by a magnet are called magnetic materials. There are only a few:

• iron
• steel (a mixture of metals that contains iron)
• nickel
• cobalt

So a magnet attracts iron nails, steel pins, paper clips, sewing needles, scissors blades, steel bottle tops and "tin" cans, which are really steel with a thin coat of tin. (Some stainless-steel spoons are made of a kind of steel that is not attracted, so always test.)

2Non-magnetic materials

Materials that are not attracted are called non-magnetic materials: plastic, wood, paper, rubber, glass, cloth, stone and water. And here is the surprise: most metals are non-magnetic too. Copper, aluminium, brass, gold and silver are not attracted by a magnet. So the aluminium drink can and a copper wire stay where they are.

3Investigate

Collect ten small objects. Copy this table, write your guess, then test each object with a magnet.

4Magnetic force works through materials

Put a paper clip on the table and hold a magnet above it with a sheet of paper in between. The clip still jumps to the magnet. Magnetic force can pass through paper, thin wood, plastic, glass, cloth and water. Drop a paper clip into a glass of water and you can pull it up the side of the glass with a magnet held outside.

But the force gets weaker with distance. Through a thick book, the clip is too far away, so the pull is too weak to lift it.

5Using magnetism to separate things

• Recycling centres use magnets to pull steel cans out of a pile of mixed rubbish, leaving the aluminium cans behind.
• You can separate iron filings from sand: put a magnet inside a plastic bag and stir it through the mixture; pull the bag inside out to drop the filings.
• A magnet quickly picks up dropped pins, needles or small nails.

Try it yourself

Try each one on your own first, then tap Show answer to check.