Chapter 10: Weathering

1
Chapter 10 Weathering Soil FormationSection 2
3 Rates of Weathering From Bed Rock to Soil
2
Section 2 Rates of Weathering
Chapter 10
Differential Weathering

• What Is Differential Weathering? Differential
  weathering is a process by which softer, less
  weather resistant rock wears away and leaves
  harder, more weather resistant rock. The image
  below is an example of differential weathering.

3
Section 2 Rates of Weathering
Chapter 10
The Shape of Rocks

• Surface Area The more surface area of a rock
  that is exposed to weathering, the faster the
  rock will be worn down.
• Increasing the Rate of Weathering If a large
  rock is broken down into smaller fragments,
  weathering of the rock happens much more quickly.

4
Section 2 Rates of Weathering
Chapter 10
5
Section 2 Rates of Weathering
Chapter 10
Weathering and Climate

• What Is Climate? Climate is the average weather
  condition in an area over a LONG period of time.
• Temperature and Water The rate of chemical
  weathering happens faster in warm, humid
  climates. Water also increases the rate of
  mechanical weathering.

6
Section 2 Rates of Weathering
Chapter 10
Weathering and Elevation

• High Elevations Rocks at higher elevations, as
  on a mountain, are exposed to more wind, rain,
  and ice than rocks at lower elevations.
• Steep Slopes The steepness of mountain slopes
  increases the effects of mechanical and chemical
  weathering. Steep slopes cause water and
  sediments to quickly run down the side of the
  mountain.

7
Section 3 From Bedrock to Soil
Chapter 10
The Source of Soil

• What Is Soil? Soil is a loose mixture of small
• mineral fragments,
• organic material,
• water and air
• that can support the growth of vegetation.
• Residual and Transported Soil Soil that remains
  above its parent rock is called residual soil.
  Soil that is blown or washed away from its parent
  rock is called transported soil.

8
Section 3 From Bedrock to Soil
Chapter 10
Soil Properties

• Soil Texture and Soil Structure
• Soil texture is the soil quality that is based on
  the proportions (ex. size shape) of soil
  particles.
• Soil structure is the arrangement of soil
  particles (ex. smaller pieces on top larger on
  the bottom.)

9
Chapter 10
Section 3 From Bedrock to Soil
10
Section 3 From Bedrock to Soil
Chapter 10
Soil Properties, continued

• Soil Fertility A soils ability to hold
  nutrients and to supply nutrients to a plant is
  described as soil fertility.
• Soil Horizons Because of the way soil forms,
  soil often ends up in a series of layers called
  horizons.
• Soil pH Soils can be acidic or basic. The pH
  scale is used to measure how acidic or basic a
  soil is.

11
Section 3 From Bedrock to Soil
Chapter 10
Soil and Climate

• Tropical Rain Forest Climates The warm soil in
  tropical rain forest climates allows dead plants
  and animals to decay easily. This provides rich
  humus to the soil.
• Desert Climates The lack of rain in desert
  climates leads to low rates of chemical and
  mechanical weathering.

12
Section 3 From Bedrock to Soil
Chapter 10
Soil and Climate, continued

• Temperate Forest and Grassland Climates
  Temperate forest and grassland climates get
  enough rain to cause a high level of chemical
  weathering, but not too much that nutrients are
  leached out.
• Arctic Climates In arctic climates, as in desert
  climates, chemical weathering occurs very slowly.
  Low temperatures slow the formation of humus.

13

• Show SOIL Brain Pop Video