For primary science, all the investigations needed can centre around the simple electro-magnet. This can be made by winding about 20-40 tight, neat turns around an iron nail and connecting the ends of this coil to 1 or 2 torch-sized 1.5v batteries. Once used, the nail may retain some magnetism, even when the current is switched off

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Some Key Questions

• Can you make an electro-magnet using ..............

• How can you make your electro-magnet lift more paper clips?

• How can you reverse the polarity of your magnet?

• Can you use electro-magnetism and Lego-Technik to raise and lower a barrier or signal?

• Can you make an electro-magnetic lock for this box?

• The magnetic effect can be adequately produced by 2-3 1.5v batteries.

• Higher voltages or mains driven Lab Packs may cause more effects than you need!

• The electro-mag coil can get surprisingly hot especially when thin wire is used or a number of batteries.

• Do not use rechargeable batteries for this work - they may overheat.

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