1. Weathering Students will be able to describe and give examples of chemical and physical weathering.

2. Weathering
The breakdown of materials on Earth’s crust into smaller pieces.

3. Two Types of Weathering Venn Diagram
Mechanical Weathering
Chemical Weathering

4. Mechanical Weathering
Process by which rocks are broken down into smaller pieces by external conditions.
Types of Mechanical Weathering
Frost Action
Ice Wedging
Wind
Water
Abrasion
Plant growth
Animals

5. Ice wedging: water is confined in cracks or pores then freezing on the rock surface and downward into the rock, solidifying and expanding deeper inside, thus wedging the rocks apart.

6. Ice Wedging

7. Ice wedging slowly breaks up this sedimentary rock into unusual shapes.

8. Abrasion Water Moves rocks, making them hit each other Wind
Blows sand against rocks
Gravity
Rocks rub against each other as they slide downhill

9. These rocks have been blasted by wind and sand causing them to become rounded.

10. Water
Rivers, streams, and runoff

11. This is a picture of the Half Dome
This is a picture of the Half Dome. The rock is peeling away from the mountain in layers just like an onion. This is exfoliation. (Abrasion)

12. Plant Growth

13. Plant growth
The tree is growing in the rock and soon the rock will break apart because of the tree roots.

14. Animals

15. Chemical Weathering
The process that breaks down rock through chemical changes. Greatest in warm/wet environments.
The agents of chemical weathering
Water
Acid in ground water
Living organisms
Acid Precipitation (rain, snow)
Oxygen

16. Water
Water weathers rock by dissolving it

17. Acids in Groundwater: Caves and caverns typically form in limestone stalactites - hang from ceiling stalagmites - on the ground

18. The lichen covered boulder produces a habitat for mosses and eventually higher plants which continue the breakdown of the rock surface by producing weak acids.

19. Acid Precipitation to
Acid precipitation has eaten away this limestone statue. Rain, sleet, ice snow, that contains a high concentration of acids.

20. Oxygen the second most common element in the air we breathe, reacts with iron in minerals to form iron oxide minerals, e.g. hematite (rust). As many minerals contain iron, it is not unusual to see red-colored rocks like the example from Arches National Park shown here.

21. Weathering and Erosion Video
What is an example of weathering and erosion in the restroom?
Weathering means _________________. Erosion means ____________________.
What 3 ways does water cause weathering? 1. 2. 3.
What are the 3 types of weathering?
What are the 2 types of erosion?

22. Karst Topography
A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams.
Created by chemical weathering of limestone

23. Karst Topography Video
What are karst photography examples?
Why is pollution of karst land forms harmful to the environment?
Where are there a lot of karst environments?
How does pollution affect cave systems outside of urban environments?
What university is the leader in karst topography research?
Where can you find materials on karst topography online?

24. Features of Karst: Sinkholes

25. Features of Karst: Caves

26. Features of Karst: Disappearing Streams

27. Wind

28. Ice Wedging