1. • Rocks are broken down in situ
• In situ means at the original place
• Causes of weathering
Extreme Freeze- Action of Action of
temperature thaw water plants
change action

2. In the day, very high temperature heats up
the surface of the rock and causes it to
expand.
At night, very low temperature cools the
surface of the rock and causes it to contract.
Alternate expansion and contraction of the
rock surface weakens the rock.
Over time, the rock surface will peel off.

4. Joints

10. When temperature falls below freezing point,
water in the cracks of rock turns into ice.
The ice will expand, widening the cracks.
When temperature rises above freezing
point, the ice in the crack will melt.
Repeated freezing and melting will cause the
cracks to become wider and the rocks will
break apart.

12. Water
freezing
in the joint

14. Joint is
widened
and
deepened

15. Rock breaks down

17. • Rain will combine with carbon dioxide in
the air to form acid rain.
• The acid rain will seep into the cracks of
rocks and dissolve part of the rocks.
• Over time, the acid rain can corrode
landforms and buildings.

20. • Seeds can be carried by wind into cracks of
rocks.
• Roots can grow into the cracks of rocks
and widen the cracks.
• Over time, the rocks may break apart.

23. • Rocks are broken down and are
removed from their original site
• Causes of erosion
Waves Wind River Flow

24. • Waves will hit the rocks on the beach
constantly.
• The rocks will be broken down either by the
force of the water or by the materials carried
by the waves.
• The broken rocks will be removed.
• Over time, features such as cliff, cave and
arch may be formed.

29. • Wind picks up sand in the deserts and hits
against the rock surface.
• As sand is heavy, it can only be carried by
wind to a certain height.
• Wind erosion can therefore take place near
the base of rocks.

31. • Rivers have energy to carry small materials
like sand and silt, as well as large materials
like pebbles.
• These materials will erode river beds and
river banks along the path of the river.
• Over time, the river will deepen and lower
the Earth’s surface.

35. Broken rocks together with
decomposed leaf litter will form fertile
soil which is good for farming. (+)
Beautiful landscapes such as river
valleys, will be formed and attracting
tourists. The country’s economy will
prosper from the earnings from tourism.
(+)

36. However, erosion can bring negative
impact too. Landslides may occur and
there will be a loss of lives and houses
will be destroyed. (-)
Statues will be corroded and destroyed.
Government has to spend large sum of
money to maintain the statues
regularly. (-)

37. Physical landscapes will be
destroyed and fewer tourists will
visit the areas. The country’s
economy will be affected as less
income is earned from tourism. (-)