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

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

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

6.  Do you think rock can become soil?
How?

8. Objectives:
Using the information in the table,
1.Trace the formation of the soil from rocks; &
2.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?”

9. Analysis:
1) What are the factors exhibited in
drawing A? What process is involved?
2) What factors are exhibited in
drawing B? What process is involved?
3) What are the factors exhibited in
drawing C?

10. Analysis:
1) 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.

11. Analysis:
2) 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.

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

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

14. 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.

15. 1. 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.

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

17. 3. Biological Action
a) 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.

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

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

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

21. 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.

22. 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).

23. 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.

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

26. 2 Types of Weathering
1.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)

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

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

29. 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.