Physical Weathering

A presentation of lesson for the topic of Weathering in Science 7

1. Why is the Philippines call an archipelago? ANSWER: Philippines is made up of group of islands.

2. What landmasses are near the Philippines? ANSWER: Asian Continent, Malaysia, Taiwan, Indonesian Archipelago, Japan, Australian Continent.

3. Do you think rock can become soil? How?

4. Story Life of a Rock

5. Objectives: Using the information in the table, Trace the formation of the soil from rocks; & Identify the factors acting together on rocks to form soil.   Materials Needed: manila paper, drawing pens, coloring materials Activity 3: “How are soils formed from Rocks?”

6. Analysis: What are the factors exhibited in drawing A? What process is involved? What factors are exhibited in drawing B? What process is involved? What are the factors exhibited in drawing C?

7. Analysis: What are the factors exhibited in drawing A? What process is involved? Answer: The factor exhibited in drawing A is hot temperature . The process involved is THERMAL STRESS.

8. Analysis: What factors are exhibited in drawing B? What process is involved? Answer: The factor exhibited in drawing B is cold temperature . The process involved is THERMAL STRESS .

9. Analysis: What are the factors exhibited in drawing C? Answer: The factor exhibited in drawing C is Rainfall .

10. Lesson 2: Physical Weathering, Chemical Weathering, and Factors of Rock Weathering Module 1: The Philippine Environment

11. Soil covers the entire Earth. Temperature , rainfall , chemical changes , and biological action act together to continuously form soil. Climate , expressed as both temperature and rainfall effects, is often considered the most powerful soil-forming factor.

12. Temperature During the day the rock are heated and then expand. At night, they are cooled and then contract. Since rocks are composed of minerals, these minerals expand and contract too. This alternate expansion and contraction causes the rocks to crack, especially if the minerals expand and contract in unequal amounts.

13. Rainfall/Water Enter the cracks in the rocks it freezes, then expand causing the rocks to split.

14. Biological Action Roots of Trees Some seeds are accidentally thrown into the cracks in rocks. When they grow, the roots creep in the roots and force of their growing can split rocks.

15. Biological Action Burrowing Animals Animals such as earthworms, ants and the larvae of other insects dig into the rocks, thus exposing fresh surfaces to further weathering.

16. Wind Carries load of fine rocks particles may rub or peel off and expose rock surfaces.

17. Human Activities Rocks break down doing construction of roads and building, digging and quarrying.

18. In chemical weathering , the composition of the rock is altered. A new product which easily crumbles to pieces is formed. Chemical weathering is brought about by a chemical reaction between the minerals in the rocks and carbon dioxide, oxygen or water.

19. Climate (temperature and rainfall) is a significant factor not only in soil formation but also in sustaining diversity of plants and animals in the country. On the other hand, water also directly affects the movement of soluble soil nutrients from the topsoil to deep under the ground (leaching).

20. These nutrients may no longer be available to shallow rooted plants. Acidic rainwater may also contribute to the loss of minerals in soil resulting in low yield. So, rainfall determines the kind of vegetation in an area.

21. Weathering is the breaking down process of rocks into smaller pieces by natural processes.

22. 2 Types of Weathering Physical Weathering – the process of breaking down rocks without changing their chemical composition. (the mechanical breaking of rocks) 2. Chemical Weathering – breaks down rocks by changing their chemical composition. (chemical decay of rocks )

23. Why climate is often considered the most powerful soil forming factors?

24. ASSESSMENT I: Sequencing using numbers. Write the correct order of processes in weathering by putting the number before each number.  

25. ASSESSMENT II: Match column A which corresponds to column B ___1. Temperature a. Carries load of fine rocks particles may rub or peel off and expose rock surfaces. ___2. Rainfall b. Alternate heating and cooling and causing contraction and expansion that causes rock to crack. ___3. Biological Action   c. Creep in the roots and force of their growing can split rocks. ___4. Wind d. Rocks break down doing construction of roads and building, digging and quarrying. ___5. Human activities e. Enter the cracks in the rocks it freezes, then expand causing the rocks to split.