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Drawing things Drawing things togethertogether

About how the scenery is About how the scenery is changedchanged

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So far …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 volcanoesSo we are now going back to scenery but from a different angle

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Do you remember Do you remember what were the 2 what were the 2

types of processes types of processes that create that create sediment?sediment?

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Looking at Looking at weatheringweathering briefly briefly firstfirst

Weathering is the break down of the rocks by various processes. There are 3 broad types of weatheringP..B..C..Can you remember how each works?

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What does What does erosionerosion mean? 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

TransportationTransportationDepositionDeposition

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 erosionagents of erosion – the things that wear the rock away? (3 all together)

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There are 3 processes at work There are 3 processes at work

Erosion Transport Deposition

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

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Wind ErosionWind Erosion

Typical sharp-edged wind erosion Grand Canyon

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Water Erosion Water Erosion (Near the source of a river)(Near the source of a river)

Notice the 'V' profile, absence

of vegetation and steep slopes

.

How a waterfall and gorge are

formed

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Water Erosion Water Erosion (Nearer the mouth of a river)(Nearer the mouth of a river)

.

See how the edge of this river has been eroded to form a

river cliff

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Water Erosion - CoastWater Erosion - Coast

.

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There is also ice There is also ice erosion erosion

That is what glaciers do- That is what glaciers do- maybe another time?maybe another time?

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TransportationTransportationIs the movement of eroded material by water, wind or ice.And is a bit difficult to see!

But here is a lot of sediment

AndThat is a tree trunk floating

down the River Wye last October

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TransportationTransportationAnd 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

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Deposition is a bit easier!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.

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Deposition is a bit easier!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 dunesLocation:

Sabria, Tunisia

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Deposition is a bit easier!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

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ReviewReview1. 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?

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How do these How do these processes work?processes work?

As applied to coasts, but As applied to coasts, but they work river rivers toothey work river rivers too

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There are 3 processes at work There are 3 processes at work

Erosion Transport Deposition

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

Remember when we talked about rocks? Which rocks were made by wearing away, carrying the bits and then dropping them?

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Erosion 1Erosion 1Attrition 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

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

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Erosion 3Erosion 3Hydraulic 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

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

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If you would like to If you would like to watch the animation watch the animation

from which the from which the diagrams for erosion, diagrams for erosion, look here! (I borrowed look here! (I borrowed

it from the BBC!)it from the BBC!)http://ysgol-rhyngrwyd.wihttp://ysgol-rhyngrwyd.wikispaces.com/Unit+4+Chkispaces.com/Unit+4+Changing+Earthanging+Earth

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Transportation 1Transportation 1

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 elseThese materials are known as its load.its load. The load is carried along by four processes.

traction traction saltation saltation suspension suspension solutionsolution

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

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Transportation 3Transportation 3

Saltation is when small pebbles bounce along and leapfrog over each other.

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Transportation 4Transportation 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!

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Transportation 5Transportation 5Transportation 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!

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DepositionDeposition

A waves drop their loadtheir 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 waterwaves enter a sheltered areathere is little wind

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Can you sort the Can you sort the words we have words we have

learnt into learnt into erosion and erosion and deposition?deposition?Try here!!Try here!!

http://classtools.net/my/dhttp://classtools.net/my/dustbin35961TESTER.htmustbin35961TESTER.htm

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Match the word to the definitionMatch the word to the definitionAttritionAbrasionHydraulic actionCorrosionTractionSaltationSuspensionSolution

The water dissolving away the cliffsThe force of the water wearing away the cliffsTiny particles of clay or sand being carried away by floating in the wavesRocks hitting each other, breaking pieces off, making them smaller and smootherRocks wearing away the coast lineLarger boulders being dragged along the floor of the oceanDissolved chemical being taken away by the waveSmaller pebbles leapfrogging over each other as they move