Thi is a presentation about the topic of grade 11. 2nd quarter

2. Weathering

3. differentiate mechanical
weathering and chemical
weathering; and
1
At the end
of the
lesson, you
should be
able to:
2
describe how rocks
undergo weathering;
enumerate the factors
that contribute to
weathering.
3

4. enumerate the factors
affecting soil erosion;
and
4
At the end
of the
lesson, you
should be
able to:
5
explain the process of
soil erosion and its types;
identify measures to
prevent soil erosion.
6

5. • Weathering is the process of breaking down rocks present
at Earth’s surface.
• Weathering can happens in the presence of the action of
rainwater, variable extreme temperature, and different
biological activities.
Weathering

6. • Mechanical weathering is a
process wherein rocks are
broken down into smaller
pieces without changing
their chemical composition
due to several factors like
fluctuating temperatures
and pressure, and biological
activity.
Mechanical Weathering
Rocks by the sea change shape due
to the force of water during high tide.

7. • Frost wedging is a process
that involves repeated cycles
of freezing and thawing of
ice.
• It happens when there is
sufficient moisture; pre-
existing cracks; and when
temperatures frequently
rise and fall
Types of Mechanical Weathering
Weathering of rocks through frost
wedging

8. • Salt crystal growth is a
process that happens when
seawater penetrates
crevices in rocks which are
found mostly in rocky
shorelines and arid regions.
• Salt crystals expand when
subjected to an increase in
temperature that causes the
widening of cracks.
Types of Mechanical Weathering
Rock weathering in beaches

9. • Biological activity is the
action of organisms including
plants and animals reduces
the size of rocks and
minerals which make rocks
more susceptible to chemical
weathering.
Types of Mechanical Weathering
Weathering by roots of plants

10. • Unloading happens through
erosion or uplift, thick
layers of sediments
overlying deeply buried in
rocks are removed. This
process is termed unloading.
Types of Mechanical Weathering
Unloading of rocks

11. • Chemical weathering is
a process wherein rock
materials are changed
into other substances
that have different
physical and chemical
compositions.
Chemical Weathering
Chemical weathering

12. • Dissolution is a process wherein a solid (i.e., halite) dissolves
in a liquid (i.e., water).
• Hydrolysis is a process where water reacts with a mineral to
form a new mineral.
• Oxidation is a where chemical combination of oxygen with a
mineral to form an entirely different mineral in which at least
one of the elements has a higher ionic charge.
Types of Chemical Weathering

13. • Climate mainly includes the amount of moisture in the air
and temperature where weathering takes place.
• The higher the elevation of an area, the more susceptible
it is to weathering since it is more exposed to environmental
factors.
Factors Affecting Weathering of Rocks

14. • Weathering rapidly occurs when there is a large surface area
exposed to surface processes.
• When a block is broken into smaller pieces, it has a larger total
surface area which makes it more susceptible to weathering.
Factors Affecting Weathering of Rocks
A block that is broken into smaller pieces
has a higher total surface area.

15. Erosion

16. • Erosion is the transportation of weathered rocks.
• Agents like running water or rivers, wind, gravity,
groundwater, wave currents, and glaciers contribute to
erosion.
• Erosion has different types: water erosion, wind erosion,
and glacial erosion.
Erosion

17. • Water erosion is a type of
erosion where water carries
the sediments to different
bodies of water such as rivers.
• The high amount of rainfall
contributes to susceptibility of
the soil to water erosion.
Types of Erosion
Grand Canyon in Arizona, a
product of water erosion

18. • Wind erosion happens
when light materials, such
as small rocks and pebbles,
are carried by the wind to
different places.
Types of Erosion
Rock shaped by wind erosion

19. • Glacial erosion happens
when a glacier, or a river of
highly-compact ice, move
downhill due to its weight.
• It plucks chunks of rocks and
causes scraping between the
ice and the rock.
Types of Erosion
Landform formed by
glacial erosion

20. • Soil erodibility is the vulnerability of soil to erosion caused
by rainfall intensity, soil properties, crop cover, and slope.
• The texture of the soil is the most significant contributing
factor to erodibility although structure, organic matter, and
permeability may also affect it.
Causes of Erosion

21. • Overgrazing by livestock or
by indigenous animals may
remove vegetation leaving
the soil more vulnerable to
erosion.
Causes of Erosion
Overgrazing

22. • Cutting of trees and removal of vegetation to provide
lumber can also result in large amounts of erosion.
• Use of pesticides, herbicides, and fuel oils also pollutes
the soil. Salt can also contaminate soil due to the high
salinity of irrigation water as it passes over croplands.
Causes of Erosion

23. • Steep terrains are shaped to
produce flat areas
• Reducing farmland
conversion
• Planting vegetation
• Application of organic
fertilizer
• Building retaining walls
Preventing Soil Erosion
Rice Terraces

25. Mass Wasting

26. describe the different
types of movement of
mass wasting; and
1
At the end
of the
lesson, you
should be
able to:
2
identify the factors that
cause mass wasting;
enumerate different
measures to prevent
mass wasting.
3

27. enumerate the properties
of sediments; and
4
At the end
of the
lesson, you
should be
able to:
5
describe the process of
sedimentation;
determine the effects of
excessive sedimentation.
6

28. • Mass wasting is a downslope movement of rock,
regolith/unconsolidated material, and soil under the
influence of gravity.
• It is different from erosion because mass wasting does not
need any transporting medium such as wind, water, or
glacial ice.
Mass Wasting

29. • When a stream undercuts a valley wall or when waves
started to pound on the base of a cliff, oversteepened
slopes are created.
Factors that Cause Weakening of Slopes
Angle of repose of different materials

30. • Slightly wet
unconsolidated
materials exhibit a
very high angle of
repose due to the
surface tension of
water as it holds the
grain together.
Factors that Cause Weakening of Slopes
Effect of water on sand

31. • If the amount of
water is too much,
the angle of repose
becomes very small
and creates fluid-
like motion for the
grains.
Factors that Cause Weakening of Slopes
Effect of water on sand

32. • Plants have extensive root system which holds the soil
and regolith together, thus preventing mass wasting or
soil erosion.
• Therefore, lack of plants may result in enhanced mass
wasting especially if large amounts of rainfall and steep
slope are present in the area.
Factors that Cause Weakening of Slopes

33. • The type of rock present in
the area may also affect the
debris flow. Igneous rocks are
less prone to mass wasting than
sedimentary rocks. The
presence of joints, fractures,
and bedding planes may
influence the occurrence of
mass wasting.
Factors that Cause Weakening of Slopes
Direction of slope and weak
zone in a rock

34. • Creep is the slow, downhill movement of rock or soil under
the influence of gravity.
• A debris flow is composed of a mixture of clay, silt, sand,
and rock fragments in which more than half of the
components are more abundant than sand.
• Mudflow has a consistency of wet concrete due to its high
water content.
Types of Mass Wasting

35. • An earthflow contains less water and therefore less fluid
than a mudflow.
• Solifluction happens when water-saturated soil moves
downslope.
• A slump occurs when blocks of material move downhill over
a gently curved fracture in rock or regolith.
Types of Mass Wasting

37. During a rockslide, bedrock
slides downslope over a
fracture plane.
The fastest type of mass
wasting is fall. It is
characterized by rapid, free-
falling rocks.
Types of Mass Wasting
Types of Mass Wasting

38. • Hazard maps are used to identify areas susceptible to
landslides.
• Engineering measures are also applied before any hillslope
development.
• Soft mitigating measures such as information and educational
campaigns and monitoring and early warning systems are also
conducted by the local government.
Measures to Prevent Disasters

39. Sedimentation

40. • Sediments are loose, unconsolidated, solid particles from
weathering and erosion of pre-existing rocks, precipitation
of minerals dissolved in water, and remains of plants and
animals.
• The process in which solid materials are deposited
horizontally after it is transported by different agents of
sediment transport such as water and wind is called
sedimentation.
Sediments and Sedimentation

41. • Sphericity refers to the
degree by which a material
approaches the shape of a
sphere.
• Roundness is the degree of
abrasion as shown by the
sharpness of the sediment’s
edges and corners.
Properties of Sediments
Roundness and Sphericity

42. • Sorting describes the degree of uniformity of grain sizes of
sediments. Sediments are sorted based on their density
caused by the energy of the transporting medium.
Properties of Sediments
Sorting of sediments

43. • When the velocity of the transporting medium becomes
low, heavier sediments are left behind and begin to be
deposited.
• Gravel and coarser particles are carried by high energy
current or streams with high competence. Sand and finer
sediments are mostly transported through wind and wave
action.
Properties of Sediments

44. Earth’s Internal Heat

45. The learners should be able to:
• describe where the Earth’s internal heat
comes from (S11/12ES-IIb-c23);
• describe how magma is formed.

46. You will not feel the heat that
comes from inside the Earth.
However, you must know about
the heat in the interior of Earth
since this builds mountains,
moves continents, and causes
earthquakes.
Where does all of this internal
heat come from?

47. • The internal heat of the Earth fuels the planet’s dynamic
processes including plate movements, earthquakes, and
volcanism.
• Earth’s internal heat is produced by residual heat
(extraterrestrial impacts and gravitational contraction) and
radiogenic heat.
Internal Heat of the Earth

48. Extraterrestrial Impacts
• As proposed in the
Nebular theory, the
Earth was formed
through accretion
of particles from a
rotating cloud.
Residual Heat
The accretion of fragments that results
from formation of a planet.

49. Extraterrestrial Impacts
• The great amount of
kinetic energy is
produced by the moving
extraterrestrial objects
which were then
converted to heat energy.
Residual Heat
The accretion of fragments that results
from formation of a planet.

50. Gravitational Contraction
• Collapsed clouds occur because accretion of more
materials led to an increase in the gravitational
attraction causing the contraction of the Earth into a
smaller volume which will then enable them to spin faster.
Residual Heat

51. Gravitational Contraction
• The compaction of dust
clouds resulted in the
conversion of
gravitational energy
into heat energy.
Residual Heat
A collapsed cloud due to the influence
of gravity

52. • Unstable elements
undergo radioactive decay
to attain a more stable
form.
• The process of radioactive
decay produces heat as a
byproduct.
Radiogenic Heat
Radiogenic heat is a by-product of
radioactive isotope decays.

53. • Earth’s thermal budget
is the measure of the
amount of heat that is
released at the surface
and produced in the
interior.
Earth's Thermal Budget
Most of the energy produced by Sun is
absorbed and scattered by Earth on the
ground and on its atmosphere.

54. • Around 30% of the solar energy that reaches the surface
of Earth is reflected back to space by the clouds,
atmosphere and light-colored areas (deserts and areas
covered with ice and snow).
• The remaining 70% of the solar energy is absorbed by
the atmosphere, land, and oceans.
Earth's Thermal Budget

55. Magmatism: How Magma is
Formed

56. • Magma is defined as
molten rock material
produced by partial melting
of the mantle and crust. It
contains liquids, gases,
crystals and rock fragments.
Magma
Rocks melt as a result of the
addition of volatiles.

57. Temperature
• Temperature increases
with depth, which is
called geothermal
gradient. This increase
will obviously induce
melting.
Formation of Magma
Temperature increases with depth in
Earth’s internal structure.

58. Volatiles
• Volatiles are substances that evaporate easily and can exist
in gaseous form in the surface of Earth.
• Examples of this kind of substances are water and carbon
dioxide. When volatiles mix with hot mantle rock, magma
forms.
Formation of Magma

59. Volatiles
• When water or carbon dioxide are introduced to rock, flux
melting occurs which cause the rock to melt.
• Flux melting is the process of reducing a substance's melting
point by introducing impurities. When volatiles are added to
rocks, their melting point decreases.
Formation of Magma

60. • Magmatism occurs along plate boundaries or margins and
sometimes within the plate. Cracks on Earth's crust are the
result of these plate boundaries.
• In effect, hot mantle rock penetrates the crust and
becomes magma.
Magmatism