electromagnet

Everyday

An electromagnet is a magnet made by passing electricity through a coil of wire, often wrapped around an iron core; it works only while the electricity is on. tree →

In the lessons

In science lessons pupils make an electromagnet with a battery, wire and an iron nail, and test how many paper clips it picks up. Electromagnets are used in scrapyard cranes, doorbells, speakers, motors and MRI scanners. Phrases: make an electromagnet, switch off the electromagnet, coil of wire.

Examples

• We made an electromagnet with a nail, wire and a battery. tree →
• The electromagnet picked up 12 paper clips. tree →
• When we switched it off, the clips fell. tree →
• A crane with a huge electromagnet lifts old cars. tree →
• More turns of wire make the electromagnet stronger. tree →
• An electric doorbell has a small electromagnet inside. tree →

Note

Starts with a vowel sound: an electromagnet. Countable. Unlike a permanent magnet, you can switch it on and off. It is made stronger by more coils, more current (a bigger battery), or an iron core. In tests you count clips to compare strength.