Magnets and magnetism are features of modern life that we often take for granted. Magnets are used in every home - in simple fridge magnets, as catches on cupboard doors and in the rubber-coated magnetic strip that holds the freezer door shut. You may have a phone case, handbag or necklace that uses magnetism to keep it shut. Magnetism is used to record data on swipe cards, video and audio tapes, to sort cans in recycling centres and to move crushed vehicles around in scrap yards.
What do I need to know?
Use the background information below to inform your planning and help you support young children's scientific learning - it is not intended that children in the Foundation Stage are taught these facts.
What is magnetism?
Nobody can answer this question fully. It is easier to describe what magnets do than to say what magnetism is.
Magnetism has been known about since at least 2,000 years ago, when the properties of a particular type of iron ore called lodestone were discovered. Pieces of lodestone, which occurs naturally in rocks in some parts of the world, were used as early compasses because they turn to point in a north-south direction.
Later discoveries found that magnetism is a particular property of some metals such as iron, cobalt and nickel, and combinations of metals (alloys) such as steel.
The Earth as a magnet
The Earth behaves as if it is a giant magnet, with a north and a south pole; these are near, but not in exactly the same place as the geographical North and South Poles. Around the Earth, like every other magnet, there is an invisible force of magnetism called a force field. A compass has a free-turning magnetic pointer which interacts with the Earth's force field and always moves to point north.
How is a magnet made?
Inside a piece of iron or other magnetic metal are millions of tiny particles, all jumbled up. When a magnet is placed next to the piece of metal, the particles line up to face in one direction and the piece of metal becomes a magnet itself. This is why a string of paperclips will hang from the end of a magnet. The stronger the magnet, the greater the force of magnetism, and the longer the string of paperclips can be.
Using magnets Every magnet has a north and a south pole. You will find that 'like poles'
(north/north or south/south) repel, or move away from each other when brought together. 'Unlike poles' (north/ south) attract or stick to one another.
Magnets come in different shapes:
- bar magnets with the north and south poles at opposite ends
- horseshoe magnets with the north and south poles at either end of the horseshoe
- ring magnets with the north and south poles on opposite surfaces of the ring.
Magnets will lose their magnetism if they are dropped or heated up or if the like poles are forced together regularly - it gets the particles confused! Store and use magnets carefully and don't let them anywhere near electrical equipment, including computers, videotapes, DVD players and televisions.
Magnetic surprises
Small changes in the way alloys are made can affect whether they are magnetic or not. For example, stainless steel which has had chromium added to it is not magnetic.
The force of magnetism can act through other materials - plastic-coated paper clips will be attracted to magnets, and metallic objects can be moved around on a table top by moving a strong magnet underneath.
Modern technology has created some interesting uses for magnetism - paint, rubber strip and ceramic magnets. The magnetic properties of all these materials come from the small amounts of iron that are incorporated in them.
Investigating
What will a magnet attract?
What you need: selection of bar or horseshoe magnets; selection of objects made of different materials including metal, wood, cardboard, plastic and rubber; access to different areas of your setting, indoors and out.
What to do
- Give the children time to investigate what happens when the magnets come into contact with the different objects. Which objects stick to the magnet? Which objects do not?
- Help the children to sort the objects into two groups: 'Things that are attracted to a magnet' and 'Things that are not attracted to a magnet'.
- Discuss with the children what the objects in each of the groups are made of. Were there any surprises?
- Give each child a magnet and encourage them to walk around the setting, both indoors and out, exploring which everyday objects are magnetic. For example, outdoors, test bricks, tree trunks, drain covers, drainpipe fixings, plant pots and garden tools. Which things will your magnet stick to?
- Before the children start their investigations, be sure to explain that they must keep the magnets away from computers, TVs and other electrical equipment.
- Encourage the children to record their findings.
The best magnet in the world
What you need:
Tray; various magnetic objects, for example, large paper clips, magnetic marbles or counters, spoons, scissors, coins; selection of magnets including bar magnets, ring magnets, magnetic wands and horseshoe magnets.
What to do
- Use the activity to let children explore which magnet they think is the best and ask them to give reasons for their choices.
- Explain that you are trying to find 'the best magnet in the world' and that you need their help.
- Place the tray of magnetic objects in an area of the room where it can be accessed by pairs of children. Give each pair of children the time to investigate the magnets and answer these two questions: Which magnet is the best? Why is it the best?
- Record the children's answers to these questions and the thinking behind their opinions. As a group, share your ideas and opinions on which is the best magnet. Does everybody agree? Why is your choice the best? Do you like anybody else's ideas?
- This is a good opportunity to discuss what is meant by 'best' - the biggest, the one that picks up the most objects, the one that picks up the biggest object, or the most attractive one?
- As an extension to this activity, introduce the children to the way that two magnets behave when they are brought together. They will be able to experience the force of the push that occurs when the like poles of two magnets repel one another. They can see that bringing unlike poles together will create a pull force as the magnets attract each other.
Vocabulary to introduce
magnet magnetic north bar pull south ring push pole horseshoe stick attract wand metal repel
Further information
- Teaching the Tricky Bits - Forces, Electricity and Magnetism and The Earth in Space by John Stringer (Hopscotch Educational Publishing)
- A wide selection of magnets, magnet sets and magnetic games are available from Reflections on Learning, www.reflectionsonlearning.co.uk 01732225850
Linda Thornton and Pat Brunton are education consultants with a special interest in science and technology for young children. They can be contacted at www.alcassociates.co.uk
