1.2 + 1.3 Rock changes and is moved

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Instruction 1.2 Rock changes

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Instruction 1.3 Rock is moved

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Weathering

The Himalayas and the Andes have much relief.

Mountain tops slowly break down. This is called weathering.

Mechanical weathering (1)

1. cracks and crevices are filled with water after a rain shower
2. the water expands as it freezes
3. cracks and crevices slowly get bigger
4. eventually the rock breaks

Mechanical weathering (2)

1. the rock expands when it is heated by the Sun
2. the rock contracts when the temperature drops below zero

What will eventually happen to the rock?
The rock will crumble.

Mechanical weathering (3)

1. plant roots grow between cracks
2. as the roots get wider, the rock may crumble

Chemical weathering

Old buildings and statues show traces of chemical weathering.

The speed at which this chemical weathering occurs depends on the climate.

.

Chemical weathering

In a warm, humid climate, the chemical weathering process isfaster than in a cold, dry climate.

Caves

Caves are created by chemical weathering.

There is limestone below the surface of the Earth. Limestone dissolves faster in acidic water than most rocks.

In the Netherlands caves are found in?

• Limburg (southern part)
  

Place the processes in the correct order.

1

2

3

4

Precipitation becomes acidic by plant roots

Limestone dissolves

Precipitation falls

Precipitation seeps down through the rock

Question

Which two forms of mechanical weathering occur mainly in a high mountain range?

• Weathering by the freezing of water and by warming up and cooling down.

Question

Which two forms of mechanical weathering occur mainly in a high mountain range?

• Weathering by the freezing of water and by warming up and cooling down.

Why?

• During the day the temperature is often above zero and at night below zero. Because the rocks are not covered with soil or plants, they warm up quickly and cool down quickly.
  

Question

Explain how weathering due to heating and cooling also occurs in deserts.

• In the desert there are big temperature differences between night and day.

When loose rock rolls down, slides or falls down a slope, it is called a mass movement.

When loose rock rolls down, slides or falls down a slope, it is called a mass movement.

Erosion

The abrasive effect of running water, wind or ice is called erosion.

Newly weathered rock is sharp and angular / round and angular in shape.

Erosion

Newly weathered rock is  sharp and angular in shape.

As the stones in the river collide and rub against each other, they slowly become rounded.
River gravel is thereby found in the upper course of the river.

Glaciers

In mountain areas, erosion can also be caused by glaciers.

Snow accumulates because it is cold and does not melt.

Due to the pressure of the snow layers, snow is turned into ice.

Due to the heavy weight of the ice, the glacier ‘flows’ slowly down the mountain.

Different valleys

Which of the following valleys is formed by a river and which by a glacier?

Explain your answer.

Different valleys

Which of the following valleys is formed by a river and which by a glacier?

Explain your answer.

Sand and clay

Hard rock crumbles, wears down and changes its composition.

Weathering and erosion cause rock to break down into small grains.

Put in order from large to small: 

clay, river gravel, sand

Sand and clay

Hard rock crumbles, wears down and changes its composition.
Weathering and erosion cause rock to break down into small grains.

From large to small: 

river gravel, sand, clay

With the naked eye you can see the grains of:
river gravel and sand.
The smallest grains are called: clay.

Question

What force on earth plays a major role in moving material
along a slope?

• Gravity

In which three ways does material move down a slope?

• By rolling, falling and sliding.

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1.2 Rock changes: 2, 3, 8

1.3 Rock is moved 2, 4, 7, 8

Finished early? Improve your map skills: workbook p. 6 and 7 

Next week

1.4 Sedimentation

Homework:

1.2 Rock changes: 2, 3, 8

1.3 Rock is moved: 2, 4, 7, 8