Constructive and deconstructive

SC 5th Grade Standards; Effects on Earths Geological Landforms

1. Constructive and
Deconstructive
Explain how natural processes (including
weathering, erosion, deposition, landslides,
volcanic eruptions, earthquakes, and floods)
affect Earth’s oceans and land in constructive
and deconstructive ways.

2. Constructive
•Processes that
create landforms
–Deposition
–Landslides
–Volcanic
eruptions
–Floods
Destructive
•Processes that
destroy landforms
–Weathering
–Erosion
–Landslides
–Volcanic eruptions
–Earthquakes
–floods

3. Weathering
•Weathering is a general term used to
describe processes that break down rocks
at or near the surface of the earth
•Weathering can be either physical or
chemical
•These processes cause the surface of the
earth to dissolve, decompose, and break
into pieces.

4. What Causes Weathering
•Water is an important cause of weathering
•Plants cause weathering when roots break
apart rock.
•Changes in temperature can break rock as
well as ice forming inside cracked
surfaces causing it to break apart even
more.
•Anything that causes rock to wear down or
break apart is a cause of weathering.

5. Erosion
•Erosion is the movement of sediments and
soil by wind, water, ice and gravity.

6. Deposition
•Deposition is the dropping, or depositing
of sediment by water, wind or ice.
•Deposition builds up new land on Earth’s
surface, like a delta at the end of a river or
the pile up of a sand dune in the desert.
•Shells on the beach are deposition by the
ocean waves.

7. Landslides
•Landslides are mass movements of land
due to gravity
•Landslides can cause buildings to fall, or
power and gas lines to break.
•Landslides even occur on the continental
slope in the ocean.

8. Volcanic Eruptions
•Volcanoes are mountains with an opening
in the Earth's crust through which magma,
gases, and ash reach Earth’s surface.
•Volcanoes can change Earth’s surface.
•When the magma erupts from the volcano
the top of the mountain can be changed,
either built up or exploded off.
•The lava and ash can destroy forests and
bury fields.

9. •Volcanic eruptions can even change
Earth’s weather patterns
•Volcanic eruptions also occur under the
oceans; these volcanoes that built up are
called seamounts.
•If a seamount rises above the ocean
surface it is called a volcanic island (for
example Hawaii and Japan)

10. Earthquakes
•Earthquakes are vibrations on Earth’s
surface caused by sudden movement in
Earth, often along a fault, a break in the
Earth’s surface.
•Some earthquakes cause little damage
and some cause a lot of damage.

11. •Large earthquakes can cause landslides
•Earthquakes under the ocean can cause
huge waves, called tsunamis that destroy
land, causing great damage if they come
ashore.

12. Floods
•Floods occur when a large amount of
water covers land that is usually dry.
•When the flood occurs, rapid erosion can
take place and move soil and sediments
away.
•When the flood recedes, new sediment is
left behind and can build up rich soil
deposits.

13. Test Preparation
•Define:
–Deposition- this is the dropping of sediment by wind, water, or
ice.
–Constructive- this type of force creates landforms
–Weathering- this is the movement of sediment by wind, water
and gravity
–Landslide- this type of movement of land is caused by gravity
–Destructive- this type of force destroys landforms
–Erosion- this is a type of process that breaks down landforms
•Ocean waves cause erosion when crashing up against
rock surfaces, therefore causing the side of the rock or
mountain to decrease in size.

14. •What contributes to physical weathering?
–Growing plants
–Flowing water
–Freezing water
•A river overflows its banks due to excessive rains and
floods the surrounding land. After the rain stops, the
water returns to the river’s original path. However, the
land surrounding land is now covered with a new soil.
This is an example of deposition of sediment –
constructive force.
•Tsunamis are caused by underwater earthquakes.
•What is one example of deposition?
–Wind building up sand dunes

15. •A fast moving stream deposits what type of material
first?
–gravel
•How does freezing of water cause weathering of rocks?
–It cracks them.
•How can a volcanic eruption be both constructive and
destructive?
–The lava and ash from volcanic eruptions can destroy forests
and bury fields. The magma and lava can form new tops of the
volcanic mountains or build up the land around the volcano. For
example, a volcano under the sea, a seamount, erupts and
erupts and erupts, building new land. This repeating eruption
creates islands such as Hawaii and Japan.

16. 5-3.2
•How is the abyssal plan different from the ocean
basin?
–The abyssal plain is flatter
•If you are playing in the sand at the beach, on
what oceanic landform are you playing?
–Continental shelf
•What are the indentations at the top of the mid-
ocean ridge called?
–Rift valley

17. •Sound waves produced by a sonar can be used
by oceanographers to help map the ocean floor.
What can you infer from the following data about
the ocean floor?
–Location B is deeper than location A
1
seconds
5
seconds
10
seconds
3
seconds
Time
before
echo is
heard
DCBA
Location

18. Be able to Label this chart!!

19. Fill in the Missing Landforms
Abyssal plainPlainsWide, flat areas of
land
Mid-ocean RidgeMountainLand which rises high
above the ground
seamountVolcanoAn opening in the
surface where lava
may flow
trenchCanyonDeep Valley with high
steep sides
RiftValleyLow land between hills
or mountains
OceanicContinentalDescriptions
Continental and Oceanic Landforms