Lesson 2 The Rhine

• Aardrijkskunde
• Middelbare school
• havo, vwo
• Leerjaar 2

Lesson 2

Weathering

For today

• Homework
• Note
• Exercise
• Get to work!

Homework

Make 1 up to 4 of lesson 1

Goals

• Students know how the alps are formed.
• Students know what weathering is.
• Students know different types of weathering and can explain the difference.

Some recap from last year

Endogenous + exogenous forces

• The earth's crust can change
  from two directions:
• Endogenous = from within the
  earth
  
• Exogenous = from outside the
  earth
  

Exogenous Forces:

•  Avalanche
  
•  Mudslide
  
•  Crumbling of rocks (weathering)
  
•  Erosion

Endogenous forces:

•  Volcanism
  
•  Earthquakes
  
•  Plate tectonics
  
•  Mountain formation
  

Forming of the Alps

Weathering

• What is weathering?
  
• The disintegration of hard rock under the influence of weather and the action of plants.
  
• Gravity rolls, falls or slides the weathered rock down the mountain , we call this a mass movement.
  

All rock weathers, but how?

Where is the solid rock and where is the weathering material?

Think-share-exchange

Why do we find fossils of marine animals high up in the Alps?

1. Think for yourself and write down an answer.
2. Share with one other person what your and their answer is.
3. Exchange within a group of four your answers

Get to work!

1. Read lesson 2 up to 'There are two types of weathering'.
2. Mark all the important sentences
3. Make exercises 1, 2a, 2b, 3a & 3d

Goals

• Students know how the alps are formed.
• Students know what weathering is.
• Students know different types of weathering and can explain the difference.

Weathering

• There are two kinds of weathering.

1. Mechanical weathering
2. Chemical weathering

Mechanical weathering

• Mechanical means it happens with some sort of movement.

1. Freezing of water (ice expands) -->  frost weathering
2. Growing plant roots --> biological weathering
3. Shrinking of rocks during cold and expanding by heat from the sun.
   
   
4. --> Frost weathering

Rainwater runs into the crevices

Rainwater in crevices freezes

How do the rocks weather overhere?

Mechanical weathering

• Roots of trees grow in the crevices
• The roots push the rock apart
• --> biological weathering

How do the rocks weather overhere?

Weathering

• --> Chemical weathering
  
• Chemical weathering: changes the composition of the rock.
• Moisture + oxygen react with rock.
  
• Iron + water + air = rust
  

What kind of weathering do you see in this photo?

Weathering

• How do you recognize from the photo
  that this sculpture has been affected
  by chemical weathering?
• Small parts of the image are dissolved.
  You can tell by the small holes.
• Colour differences.

Chemical weathering

• An example of chemical
  weathering can be found
  in limestone.
• Karst name of all
  landscape forms that are
  associated with the
  dissolution of limestone
  in water.

Get to work!

1. Read lesson 2 completely.
2. Mark all the important sentences
   
3. Make exercises 1, 2a, 2b & 3a, 3c & 3d, 4a, 5 & 6a.

Goals

• Students know how the alps are formed.
• Students know what weathering is.
• Students know different types of weathering and can explain the difference.