A short investigation to demonstrate that magnetic forces (fields) work from a distance and do not need physical contact.
- Paper clip
- Thin card/paper
Programmes of Study:
Working scientifically Lower KS2
- Make systematic and careful observations
Forces and magnets – Year 3
- notice that some forces need contact between two objects, but magnetic forces can act at a distance
- Recap on push and pull forces. Can the children name examples of these forces? Think about how objects move and how these forces enable this movement i.e. did they need contact for it to move? (Kick, throw etc. physical contact to move). If no-one mentions gravity remind them of this – a force that acts upon objects to create movement without actually touching them e.g. .A ball is thrown into the air (a push from a hand) it is then pulled back down to earth by gravity (but nothing physically touches it).
- Are there any other forces that act without physical contact? Give children a paper clip and a piece of thin card and ask them if they can make the paper clip move without touching it?
- Children should be able to demonstrate a range of movements e.g. tilting the card– gravity causes paper clip to slide – no contact; blowing the paper clip – this is a CONTACT force although you can’t see it, the air has to push the paperclip.
- Give the children a magnet and ask them to explore further. Remind them that we are trying to produce a movement without the force physically touching the object. They should be able to demonstrate the magnet attracting the paperclip from distance but it then is in physical contact. Can they remedy this? If nobody comes up with the idea of putting the card between the magnet and the paperclip suggest it and let them explore further.
- Let the children feedback on what they have found.
- Clarify that the magnets magnetic field is pulling the paper clip towards it but that the magnet doesn’t have to be touching the paper clip for this to work and that the card/paper is acting as a barrier to contact but is not stopping the magnetic attraction.
- How can we show the pull force of the magnet works from a distance? Get the children to design their own investigations.
- Measure the distance of attraction by moving a paperclip towards a magnet beside a measuring scale (ruler) at what point does it move due to the magnetic attraction?
- Try moving the paper clip through card/paper. How many sheets does it take before the attraction is no longer felt?
- How can you make sure that the test is as fair as possible?
- Design a magic trick that uses a magnet to move a paper clip without the audience seeing the magnet.
- Use a variety of magnets so that children understand that magnetic field is affected by strength of the magnet.
- Use a variety of sizes of magnets so that children are aware that size does not equal strength of magnet.