Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What are electromagnets made of?
   • An electromagnets is consists of: - a coil - a current source - possibly an iron core
2. What are the main uses of electromagnets?
   • The main uses of electromagnets are: - Door bells - Transformers - Loudspeakers - Scrap magnets - MRI machines - Headphones
3. What factors can affect the strength of an electromagnet?
   • The factors that can affect the strength of an electromagnet are: - number of coils of wire - voltage - number of magnets
4. ES - What is the motor effect?
   • The motor effect occurs when a magnetic field created by a flow of current interacts with a magnetic field from a permanent magnet.
5. ES - How is the motor effect used to create a speaker?
   • They do this by using an electromagnet held inside a permanent magnet's field. The electric current around the amplifier constantly changes, and in changing it also changes the magnetic field around the electromagnet. This causes changing attraction and repulsion between the two magnets making the electromagnet move backwards and forwards. This movement causes sound waves.