Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. How can corrosion be described?
   • Corrosion is the destruction of materials by chemical reactions with substances in the environment.
2. How can corrosion be prevented?
   • Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating.
3. What practical could be carried out to investigate the conditions needed for corrosion (rusting)?
   • A practical where a metal object e.g. a nail is kept in different conditions for example: 1. Only in air 2. Only in water 3. In air and water This would show that both air and water are needed for rusting to occur.
4. What conditions are needed for corrosion to occur?
   • Rusting is an example of corrosion. Both air and water are necessary for iron to rust.
5. What does sacrificial protection mean?
   • Some coatings are reactive and contain a more reactive metal to provide sacrificial protection, eg zinc is used to galvanise iron.
6. How is aluminium protected from further corrosion?
   • Aluminium has an oxide coating that protects the metal from further corrosion.
7. Would a more or less reactive metal be used in sacrificial protection? Give a reason for your answer.
   • A more reactive metal is used as this would prevent the less reactive metal from rusting and become weakened.