KS2 Science: Which is the strongest magnet?

Primary resources > KS2 Science > Experiments in controlled environments

Video summary

Magnets are used for many things - from fridge magnets and toys to latches on cupboard doors. They come in all shapes and sizes.

In this film, presenters Cayana and Louise test some magnets to find out which one is strongest.

To do this they set up a comparative test. They test three different magnets and measure the distance that each magnet is able to attract a paper clip.

To make the test fair, they use the same ruler and paper clip throughout.

This short film is from the BBC Teach series experiments in controlled environments.

Teacher Notes

Before Watching

Ask your learners where they have seen magnets in the classroom, at school or at home?

Go on a magnetic safari around the classroom – how many magnetic objects can your learners find? Encourage your learners to then think about what each item is made from. Ask them to create a table showing magnetic and non-magnetic materials.

Look at a range of magnets. Ask your learners which one they think is the strongest? Weakest? What features of the magnets are they basing their prediction on?

After Watching

Look again at the results from the film. Which magnet was the strongest? How did we know? Were you surprised by the results? Why? Encourage your learners to try out the investigation in the film. Do their findings match those in the film? Is there a pattern?

Ask your learners how else they could test the strength of a magnet? They might come up with lots of ingenious methods such as looking to see which magnet can pick up the most paperclips, or how many pieces of paper can be held up by a magnet on a metal table leg or fridge?

Ideas for further learning

Challenge your learners to make a game that uses magnets to make something move.

Key Scientific Ideas

• Poles - The two ends of a magnet are known as the north pole and the south pole.
• Repel - If you try to put two magnets together with the same poles pointing towards one another, the magnets will push away from each other. We say they repel each other.
• Attract - If you put two magnets together with different poles pointing towards one another, the magnets will pull towards each other. We say they attract each other.
• Magnets - There is a range of magnets commonly used in school – bar, ring and horseshoe magnets. These magnets are man-made and can lose their magnetic characteristics over time. Dropping them, heating them, or banging them can lower their magnetism.
• Magnetic - Iron is magnetic, so any metal with iron in it will be attracted to a magnet. Steel contains iron, so a steel paperclip will be attracted to a magnet too.

Developing practical enquiry skills

• Comparative test enquiries - Comparative test are an opportunity for children to make comparisons. In this case we are comparing magnets. To set up a comparative test we change one variable, measure another variable and keep all the other variables the same. It is important that we only change one variable so that we know what caused the effect.
• Prediction - A prediction is saying what might happen during an investigation. When asking learners to make a prediction, it is important to encourage them to draw upon what they already know to support their thinking.

These short film clips support teachers with practical enquiry. They can be both used as a resource for learners to watch at home. Or as a stimulus to support learners to plan and conduct their own science investigations. They link to the UK Science curricula.

Magnets

• Pupils will observe that magnets can act at a distance.
• Pupils will observe that materials containing iron are magnetic.
• Pupils may predict whether two magnets will attract or repel each other, depending on which poles are facing.

Science enquiry / Skills for working scientifically

• Pupils should plan different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary.
• Pupils should take measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate.
• Pupils should record data using tables.

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