| Method |
Precise Learning Objective |
Linked |
Question / Activity
(Designed for maximum working out) |
Stepping Stones |
Pitstop Check
(Thinking Map) |
|
Corrosion is the destruction of materials by chemical reactions with substances in the environment. |
|
How can corrosion be described? |
|
|
|
Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating. |
|
How can corrosion be prevented? Practical investigation placing nails in test tubes that contain water, oil, air or smeared with Vaseline.
Get technitians to keep for a week and ask for them back to evaluate
GF: Why are sacrifical metals used in boats? |
|
|
|
Students should be able to describe experiments and interpret results to show that both air and water are necessary for rusting. |
|
What practical could be carried out to investigate the conditions needed for corrosion (rusting)? |
|
|
|
Rusting is an example of corrosion. Both air and water are necessary for iron to rust. |
|
What conditions are needed for corrosion to occur? |
|
|
|
Some coatings are reactive and contain a more reactive metal to provide sacrificial protection, eg zinc is used to galvanise iron. |
|
What does sacrificial protection mean? |
|
|
|
Aluminium has an oxide coating that protects the metal from further corrosion. |
|
How is aluminium protected from further corrosion? |
|
|
|
Students should be able to explain sacrificial protection in terms of relative reactivity. |
|
Would a more or less reactive metal be used in sacrificial protection? Give a reason for your answer. |
|
|