This document provides an overview of weathering and erosion for geology students. It begins by listing the day's objectives of comparing and contrasting chemical and mechanical weathering and explaining what causes erosion. It then defines weathering as the breakdown of rocks by physical or chemical processes. It discusses the main causes of weathering as being water, wind, and ice. It defines the two types of weathering as physical (mechanical) and chemical weathering. For each type, it provides examples to illustrate physical weathering such as abrasion and frost action and chemical weathering such as reactions with water, acids, and air. It concludes by defining erosion as the transport of soil and sediment by forces like wind, water, and gravity and

1. Welcome back Geologists!!!
Today’s Objectives:
1.Compare and contrast chemical and mechanical
weathering.
2.Explain erosion and what causes it.

2. What is weathering?
Weathering The breakdown of rocks
by physical or chemical
processes

3. Causes of weathering
Water is one cause
of weathering
What evidence of
weathering do you see
in this picture?

4. Causes of weathering
Wind is another
cause of weathering.

5. Causes of weathering
Ice is another cause
of weathering.

6. What are the 2 types of
weathering?
The 2 types of weathering
are:
1.Physical (Mechanical)
2.Chemical

7. What is physical weathering?
Physical weathering The break down of rock into
smaller pieces by physical
means

8. Examples of physical
weathering
1. Abrasion: the grinding
and wearing away of
rock by the physical
action of other rock or
sand particles.
2. Frost action: alternate
freezing and thawing of
soil and rock

9. Examples of physical
weathering
3. Thermal expansion
– repeated daily
heating and cooling
of rock
4. Plant Roots – break
rocks apart as they grow
5. Animals – animals
burrowing through the soil-
examples ants, coyotes,
worms, mice

10. Physical weathering from what?

11. Physical weathering from what?

12. Chemical Weathering Rocks react with water,
gases, and solutions;
this will add or remove
elements from minerals.

13. Examples of Chemical
Weathering
1. Water: Rocks can be
broken/ dissolve from water
2. Acid Precipitation: Rain,
sleet, or snow with a high
amount of acids
3. Acids in groundwater:
Acids react with rocks in the
ground
4. Acids in living things:
Lichen consists of fungi and
algae and are slow-growing
plants

14. Examples of Chemical
Weathering
5. Air: oxygen in the air
reacts with elements such
as iron causing rust
6. Oxidation: An element
such as iron, combines with
oxygen to form an oxide

15. Acid Rain

16. Physical or Chemical
Weathering? Why?

17. Physical or Chemical
Weathering? Why?

18. Erosion
• Erosion is the process by which wind,
water, ice, or gravity transports soil and
sediment from one location to another.

19. Soil
• A loose mixture of
rock fragments,
organic material,
water, and air that
can support the
growth of vegetation.

20. What is vegetation?
• Vegetation is the
plant life of a region.

21. Soil Properties
• There are many different properties of soil.
Some of these properties include:
– Soil texture, soil structure, soil fertility,
and soil horizons.

23. Answer the “Quiz Yourself”
questions on your paper!!