1. What effect do destructive waves have on the coastline?
Wednesday, 19 September 2018

2. Homework: due next lesson.
Using examples explain how waves can shape the coastline (4)

3. Gigantic visual
Last lesson we studied the different types of waves that land on our coast. This lesson we will examine how the destructive waves can shape our coastline. You will continue to prepare for the Swanage field visit.

4. By the end of the lesson:
All pupils can explain what erosion is and the four types of erosion
All pupils understand how geology effects the rate of erosion
All pupils will work in groups and produce a presentation
All pupils will be able to explain how destructive waves erode cliffs

5. Thinking back.
What is a destructive wave? When are destructive waves most likely to occur? Which picture is the destructive wave? Why?

6. What impact have destructive waves had on these two landscapes?

7. Both are being shaped by erosion.

8. Erosion. What do you want to know?
What is erosion?
How does erosion happen?
Why do different rocks erode at different rates?

9. Task
In groups of 3 to 4 you are going to perform a 2-3 minute presentation on the 4 main types of erosion.
Your audience is going to be year 9 pupils who are considering doing geography next year.
You will be marked on group work, creativity (the use of resources and ideas) and vocabulary.

10. What is erosion? Use the animation to help you identify the following:
The different kinds or erosion
How each type of erosion works.

11. Processes of erosion

12. Processes of erosion Attrition
Materials carried by the waves bump into each other and so are smoothed and broken down into smaller particles.
Hydraulic action
This process involves the force of water against the coast. The waves enter cracks (faults) in the coastline and compress the air within the crack. When the wave retreats, the air in the crack expands quickly, causing a minor explosion. This process is repeated continuously.
Corrosion
This is the chemical action of sea water. The acids in the salt water slowly dissolve rocks on the coast. Limestone and chalk are particularly prone to this process.
Abrasion/Corrasion
This is the process by which the coast is worn down by material carried by the waves. Waves throw these particles against the rock, sometimes at high velocity.

13. Task
In groups of 3 to 4 you are going to perform a 2-3 minute presentation on one of the four main types of erosion.
Your target audience are year 8 pupils who are considering doing geography next year.
You will be marked on group work, creativity (the use of resources and ideas) and vocabulary.

14. Task
In your exercise book describe and explain how each type of erosion occurs. A good description will be sequenced.

15. Why do different rocks erode at different speeds?
It’s all to do with the geology of the area.
What is the difference between chalk and clay?

16. Why do different rocks erode at different speeds?
Rocks such as chalk and limestone are stronger, more resistant materials which will erode at a …………., whereas material like sand and clay ……………………….

17. Task
Draw a series of diagrams to show how cliff erode.

18. How do these types of erosion attack cliffs?
How are cliffs and wave-cut platforms formed?
Before you watch the animation can you predict what will happen?

19. Wave-cut platform
The waves attack the base of the cliff through the processes of abrasion, corrosion, hydraulic action and attrition.
Over time the cliff will be undercut and a wave-cut notch is formed.
Eventually the cliff becomes unstable and collapses. Further cliff retreat will form a wave-cut platform.

20. Task
Draw a series of annotated diagrams to show how cliff erosion happens.
You should include the following words in your annotations:
Abrasion
Attrition
Solution
Hydraulic action
Collapse
Shatters
Overhang
Platform
Notch

21. Task cliff collapses hydraulic action wave retreats
Draw a series of diagrams to show cliff foot erosion.
Use the statements to help you label the diagrams
cliff collapses
hydraulic action
wave retreats
air is trapped inside cracks
cliff is undercut
rocks thrown with waves against base of cliff
rock shatters
wave reaches base of cliff
an overhang develops
Corrasion (also known as abrasion)
explosion of air
wave advances

22. Homework: due next lesson.
Using examples explain how waves can shape the coastline (4)

23. Before you leave
Which type of erosion does each image represent?