an gi ng
nd fo rm s
3.7B; 4.7B; 5.7B

True or False: The Earth’s surface has stayed the same for thousands of years.
Think about the statement in the box above. Do you think it is a true statement or a false statement?

True or False: The Earth’s surface has stayed the same for thousands of years
The Earth’s surface is
CONSTANTLY changing!

Ch an gi ng La nd fo rm s
Let’s look at a large rock by the seaside over a period of years.
1890
1910
The rock changed over this 80 year period. In fact, it almost disappeared!
1920
1970

Ch an gi ng La nd fo rm s
1890
What do you think caused these drastic changes in the rock?
What could possibly make rock break down into smaller pieces?
1970

Weathering
The breakdown of the materials in the
Earth’s crust into smaller pieces.

Moving water can cause weathering.
What evidence of weathering do you see in this picture?

Wind can cause weathering.
Why wasn’t this mass of land weathered away?
What evidence of weathering do you see in this picture?

Ice can cause weathering.
Water can get into cracks in rocks. If the water freezes, it can push the sides of the crack farther apart, making the crack larger and larger.

Plants CAN CAUSE weathering

Erosion
The process by which water, ice, wind or gravity moves fragments of rock and soil.
What evidence of erosion do you see in this picture?

Erosion is the movement of sediments !
• Erosion gradually wears down the surface
of the earth.
• Erosion carves the
Earth's surface creating canyons, gorges, and
even beaches.
• Erosion is the process by which weathered rock and soil
(sediments) are moved from one place
to another.
What do you think has caused this rock to look this way?

Wind Erosion
• As the wind blows it picks up small particles of sand/sediment and blasts large rocks with the abrasive particles, cutting and shaping the rock.
• The intensity of wind erosion is determined by:
• The amount of wind
• The speed of the wind
• The slope of the land
• The surface of the land

Evidence of Wind Erosion

Moving water causes erosion!

Moving water causes erosion.
When rain falls to the
Earth it can evaporate, sink into the ground, or flow over the land as
Runoff.
When it flows over land, erosion occurs.
Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land.

Moving water causes erosion.
How much erosion takes place is determined by the:
• Amount of water
• Slope of the land
• Speed of the water
• Surface of the land

Moving ice causes erosion.
Glaciers wear down the landscape by picking up and carrying debris that moves across the land along with the ice.

Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses.
Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!

How much erosion takes place is determined by the:
• Size of the glacier
• Slope of the land
• Speed of the glacier
• Surface of the land

Slower
Gravity causes erosion
Landslides and Avalanches.
Faster
These are examples of mass movement
(also called landslides)

How much erosion takes place is determined by the:
• Amount of falling debris
• Slope of the land
• Speed of the falling debris
• Surface of the land

Plants CAN PREVENT erosion

Deposition
Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere else.
Deposition is the process by which sediments (small particles of rock) are laid down in new locations.
• Together, Erosion and Deposition build new landforms.
• Deltas
• Canyons
• Sand dunes
• Hills

Deposition and erosion together form deltas.
Where rivers meet the ocean is called the mouth of the river.
Soil and dirt carried by these rivers is deposited at the mouth, and new land is formed. The new, soil-rich land is known as a Delta

Weathering and erosion together form canyons.
This simple animation provides you with a visualization of how the Colorado River has
"downcut" into the rock layers of the Grand Canyon.
Canyons are large valleys created by a river or stream.
How long it took to carve the
Grand Canyon is debated by geologists.
Some estimates are between 6 and 8 million years, which is very recent by comparison.

Erosion and deposition together form sand dunes.
Wind can move erode and deposit sediments, especially when it blows across open areas with no vegetation.
Wind tears down landforms when it erodes sediments.
Wind builds up landforms when it deposits sediments.
Sand dunes are hills of sand deposited by the wind.

• The natural shapes or features on the Earth’s surface are called landforms.
• Many different types of landforms can be found on the Earth.

A canyon is a deep valley with very steep sides. Rivers often flow through canyons.

A mountain is a place on Earth’s surface that is much higher than the land around it.

A sand dune is a hill of sand that is deposited by the wind.

A valley is a long, low area of land that is surrounded by higher land.

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the exposure of these tree roots?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of these cracks in the ground?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of these cracks in the ground?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this landform?
What evidence can you give for this conclusion?

What’s the evidence???
What natural processes led to the formation of this island? What evidence can you give for this conclusion?
Notice the evidence of the delta where the river flows into the sea.

What’s the evidence???
What natural processes led to the destruction of this landform?
What evidence can you give for this conclusion?