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Weathering

WEATHERING
Weathering is a process of Denudation.
Denudation is the wearing away (or breaking down) of the earth surface. 
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Slide 1: Tekstslide
GeographySecondary Education

In deze les zitten 23 slides, met interactieve quizzen, tekstslides en 2 videos.

time-iconLesduur is: 30 min

Onderdelen in deze les

WEATHERING
Weathering is a process of Denudation.
Denudation is the wearing away (or breaking down) of the earth surface. 

Slide 1 - Tekstslide

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OBJECTIVES
We will:
Define weathering
Distinguish it from Erosion
Identify the different types of weathering
Look at the factors influencing the types of weathering

Slide 2 - Tekstslide

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What is Weathering?
Weathering as one of the Denudational processes, is different from Erosion and Mass Movement.

Slide 3 - Tekstslide

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Definition
Weathering is the process by which rocks  expoxed to the agents of weather  are broken down or decomposed (in situ) at or near the surface of the earth 

Slide 4 - Tekstslide

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Slide 5 - Video

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What is the difference between Weathering and Erosion?
A
Weathering doesn't use agents of nature, Erosion does
B
Weathering brake down rocks, erosion removes them
C
Weathering is slow while erosion is fast
D
Weathering acts on rocks but erosion doesn't

Slide 6 - Quizvraag

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What were the two types of weathering mentioned in the video?

Slide 7 - Open vraag

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Physical Weathering:
Rocks are broken down(disintigrated) into smaller and yer smaller pieces:
  1. Frost Action
  2. Heating and Cooling
  3. Wetting and Drying
  4. Salt Chrystalization
  5. Pressure Release
  6. Biotic Weathering

Chemical Weathering:
Rocks are decomposed due to chemical rection between minerals in rock and water:
  1. Oxidation
  2. Carbonation
  3. Hydration
  4. Hydrolysis
  5. Biotic Weathering
Physical and Chemical Weathering

Slide 8 - Tekstslide

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Slide 9 - Video

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Factors affecting weathering
Rock composition
Rock structue
Topography
Vegetation
Climate

Slide 10 - Tekstslide

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HOW FACTORS
AFFECTS
WEATHERING

Slide 11 - Woordweb

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STRUCTURE OF ROCKS
The rock in this image has lots of joints/cracks which increases the surface area for water and other agents of weathering to penetrate and breakdonw the rock

Slide 12 - Tekstslide

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Which physical weathering process do you think would best act upon the joints of this rock to weather it?
A
Heating and cooling
B
Freeze Thaw
C
Salt Crystalization
D
Pressure Release

Slide 13 - Quizvraag

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Rock Composition
The chemical composition of some rocks makes it less prone to weathering than other rocks. Granite for   example is made up of very resistant minerals. 

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Rock Composition
The chemical composition of some rocks makes it more prone to weathering than othrer rocks. Example:
Limestone is made up of calcium carbonate which is very soluble. 

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Climatic Conditions
Temperature and rainfall are important elements affecting weathering
. Chemical weathering occurs best when it is hot and wet (Tropical Conditions).
Physical weathering occurs most where there is great variation in temperatures:  are around freezing point


Conditions for Physical Weathering
Physical weathering occurs best when there are large ranges in temperature.

Slide 16 - Tekstslide

In cold regions Physical Weathering occurs best where temperature vary around freezing point.
In arid (dry) regions, like deserts, the large diurnal temperature range greatly aids physical weathering.
Vegetation
The type of natural vegetation would influence the type and rate of weathering. 
Atropical rainforest with its very high vegetation density would contribute to a great deal of biotic weathering and chemical weathering. 

Slide 17 - Tekstslide

Trees or forest vegetation would attract a greater degree of chemical and biotic weathering that grass or savannah type vegetation. 
This is due to the larger amount of vegetation cover that attracts moisture secretion of acids that contributes to decomposition and actions by animals in these habitats. 
Slope and Slope Aspect
Slopes that are gentle would contribute to more chemical weathering.
The aspect of slope that are on the windward side will  be exposed to greater chemical weathering and wetting and drying.

Slide 18 - Tekstslide

Slopes that are gentle would retain more moisture and therefore contribute to more chemical weathering.
The aspect of slope that are on the windward side will attract more rainfall and would be exposed to greater chemical weathering and wetting and drying.
What type of weathering is shown in this picture?
A
Frost weathering
B
Weathering through temperature
C
Biological weathering
D
Chemical weathering

Slide 19 - Quizvraag

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PHYSICAL WEATHERING
BIOLOGICAL WEATHERING

Slide 20 - Sleepvraag

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Physical
Weathering
Processes

Slide 21 - Woordweb

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Chemical
Weathering
Processes

Slide 22 - Woordweb

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understand lesson 

Slide 23 - Sleepvraag

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