What changes the scenery?

1. What changes the scenery?

2. The world is always changing • The plates are on the move • New rocks form when volcanic matter reaches the surface • The plates push up layers of sediments to form new mountain ranges • Mountains become smaller as they are worn away • Loose material slithers down slopes under gravity or is moved away by other forces. • It is squashed and heated and changes chemically to form new rocks – like diamonds and metals.

3. But what processes change what we can see? • These processes remove rock from mountains • There are those that carrying them from one place to another • And when they cannot carry them any further, they drop them. • Then there are processes that turn these bits and pieces into new rocks by piling them up and squashing them.

4. We are going to look at 4 processes today • 2 that removes pieces • 1 that moves • I that drops • Now one the removing processes is right on its own • But the other 3 all formed part of a whole. • So first of all lets look at the one on its own.

5. It is called weathering • Which makes you think that it is all to do with weather, which it was when they started looking at this process, but later they found it was not JUST weather that make the effects, but they went on calling it weathering anyway, just ‘cos! • There are 3 types of weathering: • Lets look briefly at the first 2 as we will not need them again when we look at glaciers and the Ice Age • Chemical weathering • Biological weathering • This one however we will meet again: • Physical weathering

6. In the picture, you see a rock that was obviously one piece – it probably have had a bit of a crack - but before the seed fell into the crack and started to grow, that was all it was. As the tree grew, it was strong enough to force the 2 parts of the rock apart! This is a brilliant example of biological weathering

7. But they all depend on similar processes. In this case, acid rain is the major player. This is granite, a very hard rock made from magma But is has weaknesses in made of minerals that will dissolve away if attacked by acid. The acid in acid rain is quite strong enough to do this So instead of one big hard solid lump of granite, you have pile of small pieces which will fall down and become smaller and smaller eventually to make soil There several types of chemical weathering

8. The last type of weathering – physical weathering – which the most weather-like of all • Freeze-thaw is one version – one we will talk again about next week, • In this, water creeps into a crack • During the night it freezes – and ice is very strong AND it takes up more space than water so it pushes sway at the rock. • Next day, the ice melts and occupies the new bigger space left by the ice • The next night that water freezes and …. • Until you see what happens in the end!

9. I just said ice takes up more space that water • I hoped if I said it quickly enough, no-one would notice! • But actually, this picture explains how I know what I said was true! • Anyone care to explain?

10. Besides weathering, there are other processes at work • What do you think these words mean? • [the pictures give hints] • We are going to skate quickly through a number of different ways these can be achieved, with the help of a number of forces, not just ice, as you will need to have an awareness of them next year. Erosion Transport Deposition

11. What is erosion? • Erosion is the way in which rock is worn away by something else • There 3 things that can do this. They are called agents of erosion – without them no erosion would take place. • I am sure in science you have come across forces? Can you think of any natural forces that could wear away and break off rock?

12. Is fairly obvious that the bank has been eroded – by what do you think?

13. This rock has also been eroded – by what this time?

14. What is going on here?

15. Finally, one you might see again! What could have given that mountain peak its peculiar shape – there is a hint in the picture!

16. So we have a group of ideas about erosion • A river can do it, • The air can • The sea can • And so can ice • But this is 4 and I said there were 3 agents of erosion • So question number 1 – which 2 of the 4 are the same in some way? • But how could bucket of water or snow, or a balloonful of air have a force? • When they have a force they would all have to be m…..?

17. OK, erosion wears away pieces of rock – so what next? • If that is all there was too it, you would have large pieces of rock surrounded by lots of fragments – but that would not really change the scenery very much, so what do you think happens then? • Think back to our 3 little men on slide 10.

18. What is happening here?

19. Another one? What is happening here? Why is it like that?

20. This is a long river of ice – what is it called? • Can you see anything apart from ice in in it? • Remember ice can erode – so what do you think is happening here?

21. You can probably work out what has happened here?

22. So now we have the agents moving the eroded material • Do you think that once the water or the wind or ice is carrying along the eroded material that it will do so for ever? • Back to slide 10 – what happens next?

23. How did all those pebbles get, where it says HERE? HERE

24. This may look like a painting – but its not – it is a photographHow did it get there?

25. How did the sand and pebbles get there?

26. How did these rocks get here? This is a glacier

27. In summary • What are the 2 processes that remove parts of the scenery – E and W? • What is the process that moves the loose material from one place to another? • What are the 3 agents of E and T? • The agents are all F, so that only when they have enough E can the break off pieces and move them. • If the agents run out of energy, then they D the load they are carrying.

28. What process do each of these pictures show and what is the agent?

29. What process do each of these pictures show and what is the agent?

30. What process do each of these pictures show and what is the agent?

31. So we have looked in general at the processes that change scenery • Also the agents that help bring it about • Armed with this, we can look at the impact of one agent, ice on scenery next week. • What does it do and how does it do it? • In the meanwhile to give you a bit of a flavour of what is to come, I want you to look at a little puzzle.

32. Homework • http://www.sln.org.uk/geography/flash/cannock01.swf • Or it is on the wiki • It is a bit of a pain to get into – just keep pressing next • I would suggest you go through it all first before you decide what to write down.