Drawing things together

1. Drawing things together About how the scenery is changed

2. So far … • We looked at • They different types of rock and how they are formed • Then there was that small diversion by way of plate tectonics and volcanoes • So we are now going back to scenery but from a different angle

3. Do you remember what were the 2 types of processes that create sediment?

4. Looking at weathering briefly first • Weathering is the break down of the rocks by various processes. There are 3 broad types of weathering • P.. • B.. • C.. • Can you remember how each works?

5. What does erosion mean? • Do you remember what we said was also part of erosion- what tended to happen afterwards? • So we have 2 other processes following it • Transportation • Deposition • There are various ways that rock can be worn away – depends a bit what was is doing it (these are called agents of erosion) • What are the agents of erosion – the things that wear the rock away? (3 all together)

6. Erosion Transport Deposition There are 3 processes at work I am using my hammer to wear away this rock I am carrying away the pieces I cannot carry them any further so I drop them

7. Wind Erosion Typical sharp-edged wind erosion Grand Canyon

8. Water Erosion (Near the source of a river) . Notice the 'V' profile, absence of vegetation and steep slopes How a waterfall and gorge are formed

9. Water Erosion (Nearer the mouth of a river) . See how the edge of this river has been eroded to form a river cliff

10. Water Erosion - Coast .

11. There is also ice erosion That is what glaciers do- maybe another time?

12. Transportation • Is the movement of eroded material by water, wind or ice. • And is a bit difficult to see! But here is a lot of sediment And That is a tree trunk floating down the River Wye last October

13. Transportation • And here we have the wind doing some transporting This one was taken in Iraq. The soldier who took the picture said they have at least one of these a week

14. Deposition is a bit easier! • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying Kiama Downs Beach, just north of Sydney Where is that? See those rocks in the foreground? They are being eroded away and will end up on the beach.

15. Deposition is a bit easier! • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying Sand dunes Location: Sabria, Tunisia

16. Deposition is a bit easier! • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying Mississippi Delta

17. Review • 1. What ere the 4 processes involved in changing the scenery? And what do each do? • 2. What are the 3 agents of erosion? • 3. We saw various pictures – these examples of which processes?

18. How do these processes work? As applied to coasts, but they work river rivers too

19. There are 3 processes at work I am using my hammer to wear away this rock I am carrying away the pieces I cannot carry them any further so I drop them Erosion Transport Deposition Remember when we talked about rocks? Which rocks were made by wearing away, carrying the bits and then dropping them?

20. Attrition is the collision of rock fragments in the water against one another. The waves carrying rocks that knock against each other and pieces get broken off, making them smoother and rounder Erosion 1

21. Abrasion occurs when rocks and stones carried by the waves wear away the base of the cliffs Erosion 2

22. Hydraulic action. When waves fall against the cliffs, air is forced into the cracks and is squashed. As the wave withdraws, the air expands causing little explosions and so the cracks become enlarged Erosion 3

23. Corrosion is the process by which water reacts chemically with soluble minerals in the rocks and dissolves them.  Erosion 4

24. If you would like to watch the animation from which the diagrams for erosion, look here! (I borrowed it from the BBC!) http://ysgol-rhyngrwyd.wikispaces.com/Unit+4+Changing+Earth

25. A waves carry or transport eroded materials such as mud, sand, boulders and dissolved materials. Sometimes this is towards the land or sometimes is it away from the land but often it is along the coast to somewhere else These materials are known as its load. The load is carried along by four processes. traction saltation suspension solution Transportation 1

26. Transportation 2 • Traction is where boulders or stones are rolled along the ocean-bed by the force of the water

27. Transportation 3 • Saltation is when small pebbles bounce along and leapfrog over each other.

28. Transportation 4 • Suspension very fine particles such as clay, silt and fine sand are carried along in the river. • They are held up by the water as they float because they are very, very small!

29. Transportation 5 • Transportation in solution is when dissolved materials resulting from corrosion (when the eroded material is dissolved out of the rocks) and are invisible to the naked eye. You cannot see anything because they are too small!

30. A waves drop their load when the speed or volume of the waves decrease. The load, which it carries, is deposited. The heavier material is deposited first and the finer material carried further. Deposition is likely to occur when: waves enter an area of shallow water waves enter a sheltered area there is little wind Deposition

31. Can you sort the words we have learnt into erosion and deposition? Try here!! http://classtools.net/my/dustbin35961TESTER.htm

32. Attrition Abrasion Hydraulic action Corrosion Traction Saltation Suspension Solution The water dissolving away the cliffs The force of the water wearing away the cliffs Tiny particles of clay or sand being carried away by floating in the waves Rocks hitting each other, breaking pieces off, making them smaller and smoother Rocks wearing away the coast line Larger boulders being dragged along the floor of the ocean Dissolved chemical being taken away by the wave Smaller pebbles leapfrogging over each other as they move Match the word to the definition