Earth Science -Stem Grade 11 - Weathering

Weathering

1. WEATHERING

2. Have you ever wondered why mountains exist, or why rocks seem to change shape over time?

3. After going through this module, you are expected to: 1. identify the different agents of weathering; 2. identify the different types of physical, chemical, and biological weathering; 3. describe physical, chemical, and biological weathering; and 4. explain how rocks undergo weathering objective

4. Weathering: A natural process of breaking rocks into smaller pieces over time. Factors: Weather, chemical reactions, biological activities. Weathering Defined

5. Water/Ice Salts Plants Animals Changing temperatures Agents of Weathering

6. Water

7. Salt Saltwater sometimes gets into the cracks and pores of rock. When it evaporates, salt crystals are left behind and grow in the cracks and pores which caused pressure on the rock and slowly break it apart.

8. Temperature changes can also contribute to weathering through the process called thermal stress . During thermal stress, rock tend to expand with heat and contract with low temperature. As this happens repeatedly, the structure of the rock weakens and over time crumbles. Temperature

9. Plants

10. ANIMALS

11. Physical Weathering Chemical Weathering Biological Weathering Types of Weathering

12. Physical weathering is caused by the effects of changing temperatures on rocks, causing the rock to break apart. The process is sometimes assisted by water . It happens especially in places where there is little soil and few plants grow, such as in mountain regions and hot deserts. It occurs either through repeated melting and freezing of water (mountains and tundra) or through expansion and contraction of the surface layer of rocks that are baked by the sun (hot deserts). Physical Weathering

13. Chemical weathering is caused by rainwater reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic. These chemical processes need water, and occur more rapidly at higher temperature, so warm, damp climates are best. Chemical weathering

14. Biological weathering of rocks occurs when rocks are weakened by different biological agents like plants and animals. Biological weathering

15. Erosion: Process transporting weathered material to new locations. Agents: Wind, water, ice. Erosion Defined

16. Weathering breaks rocks, Erosion moves them. Weathering doesn't move materials, Erosion does. Differences Weathering vs. Erosion:

17. Earth's Surface Shaping Effects on Agriculture, Construction, and Environment Importance

18. Grand Canyon Formation (Erosion) Coastal Cliffs (Erosion) Desert Rocks (Weathering) Real-Life Examples