Magnetic separation

The last stop is Shillong, the capital of Meghalaya. At their Bua's house, a carpenter is making a wooden door. He accidentally drops a few iron nails into the sawdust.

He starts picking them out one by one. The children say, "Wait!" They fetch a magnet from their Bua and ask him to move it through the sawdust. All the nails jump to the magnet! The sawdust stays behind.

Remember 'Exploring Magnets': some substances are attracted by a magnet. They are magnetic, and iron is the common example. Sawdust is not attracted: it is non-magnetic. Separating magnetic and non-magnetic substances with a magnet is called magnetic separation. It works only when one part of the mixture is magnetic.

It is used in big jobs too. Recyclers use magnets to pull iron articles out of heaps of waste. In many industries, scrap iron is lifted out of the waste with magnets fitted to a crane, so it can be recycled and reused.