Introduction presentation on weathering, denudation.

1. Weathering
The Wearing down of rocks

2. Learning intentions
• LI1-Explain what weathering is.
• LI2- Understand what erosion is.

3. Key words in this section
Weathering
Mechanical
weathering
Chemical
weathering
Erosion
Freeze-
thaw action
Acid

4. Weathering and erosion
• The rocks and soil of the Earth’s crust are
constantly being worn down by processes known
as denudation.
• The two main processes of denudation are
weathering and erosion.
https://www.youtube.com/watch?v=JpRS9N-NWsY

5. Weathering
• Weathering is the breaking down of rocks and soil that are
exposed to the weather. The broken-down material does
not move from the place where the weathering occurred.
There are two types of weathering:
• Mechanical weathering
• Chemical weathering

6. Erosion
• Erosion is the breaking down of rocks and soil
and the transportation of the eroded material.
Erosion is caused by:
• Moving water (rivers/seas)
• Moving ice (glaciers)
• Moving air (wind)

7. Mechanical weathering
Mechanical weathering breaks up rocks into
smaller pieces by putting pressure on the rock.
Freeze-thaw action is an example of mechanical
weathering.

8. Freeze-thaw
action
• Freeze-thaw action occurs high up
in mountainous areas where there
is a lot of precipitation (rain, sleet
or snow) and the temperatures
regularly rise above and fall below
freezing point (0 ºC). Temperatures
that repeatedly rise and fall are
called fluctuating temperatures.

9. Freeze-thaw action
Image: Freeze-thaw action

10. Freeze-thaw action (Example)
• Example: Freeze-thaw action occurs in upland areas like
Croagh Patrick in Co. Mayo. Temperatures here frequently
rise above and fall below freezing point

11. Learning intentions
LI1-Explain what
weathering is.
LI2- Understand
what erosion is.