Grade 4 · Unit 5: Electricity and magnetism

Which metals are magnetic?

Not all metals stick to magnets.

Testing metals

Many people think all metals are magnetic. Let us test it! Iron and steel are magnetic. So are nickel and cobalt. Aluminium, copper, brass, gold and silver are not magnetic.

Many “tin” cans are really steel with a very thin coating of tin to stop them rusting – so a magnet sticks to them.

Cans and coins

Food tins are made of steel, so a magnet sticks to them. Most drink cans are made of aluminium, so a magnet does not stick. Some coins contain steel or nickel and are attracted to magnets.

Some coins are made of steel covered with a thin layer of another metal, so they are attracted to a magnet even though they look like brass or copper.

Sorting for recycling

Recycling centres use magnets to separate steel from aluminium. The steel is pulled out by the magnet, and the aluminium is left behind. Both metals can then be melted and reused.

In Bangladesh, scrap dealers (bhangari) use magnets to sort metals quickly before selling them to be recycled.

Non-metals

Wood, plastic, glass, rubber and paper are never magnetic. So a magnet is a quick way to find iron and steel in a mixture.

Because only some metals are magnetic, a magnet is a quick test to find out whether an object contains iron or steel.

What I learnt

• I know that iron, steel, nickel and cobalt are magnetic.
• I know that most metals, like aluminium and copper, are not magnetic.