S3.10.7 For the adult
Electromagnets
Can I make a magnet that I can switch on and off?
What this chapter teaches
A current in a coil makes a magnetic field like a bar magnet. An iron core makes it much stronger, and more turns or more current make it stronger still. An iron core loses nearly all of its magnetism when the current stops.
Three questions to ask
There is no one right wording. Listen for the idea.
- Why does the clip count drop when the switch is opened?
- What are two ways to make an electromagnet stronger?
- Why is it useful that an electromagnet can be switched off?
After the chapter, the learner can
- Make an electromagnet with a nail, wire and a cell
- Test how more turns of wire change its strength
What they copy into their notebook
A current in a coil makes a magnet. An iron core makes it stronger. More turns or more cells make it stronger. Switch off and an iron core loses most of its magnetism.