Changes to the
Earth’s Surface:
Erosion
5.7B
Earth’s surface is constantly changing
and consists of useful resources.
Recognize how landforms such as
deltas, canyons, and sand dunes are
the result of changes to Earth’s surface
by wind water, and ice.
Introduction
The surface of the Earth is always changing.
Water and wind, snow and ice, all of these change
the shape of the land.
Wind can blow soil and small rocks to other places.
Water can move soil and bits of rocks to new
locations. Snow and ice can move down
mountains, picking up soil and rocks as it moves.
When any of these things happen, the shape of the
land changes and new landforms are created. This
process of moving soil and rocks to new places is
called erosion.
Beaches
Beaches are made of sand and small rocks that
have been washed up or blown along the shore.
The ocean water erodes sand from the bottom
of the sea and deposits it on the beach. Rivers
erode sediments along their path and drop them
as they flow into the ocean.
The wind is constantly changing the shape of
sand dunes by eroding and moving the sand
into new shapes. Water from waves or heavy
rain keeps changing the shape of beaches.
Cliffs and Rocks
The wind blows, the rain falls, and the waves
crash against the cliffs along the shoreline.
The soil that covers the rocks and cliffs is easily
blown away. The ocean waves also pick up the
soil and sand and move them away.
Erosion, in the form of waves, wind and moving
sediments, changes the landforms along the
shoreline over a long period of time.
A canyon is a deep valley
between cliffs, often
carved from the
landscape by rivers.
Canyons are formed
when moving water
erodes and wears away
the sides and bottoms of
a river. The water
erodes, or moves, the
soil and rocks to new
places along its path.
Canyons
Glaciers
A glacier is like a river of ice.
When snow falls and the wind blows high up in the
mountains, snow can pile up and turn into ice. The
pile of ice becomes so heavy that it starts to move
downhill. This moving ice is called a glacier.
A glacier moves very slowly. The heavy ice breaks
up rocks and makes big holes and u-shaped valleys
in the land. When rain falls in these holes and
valleys, a new lake or river is made. The moving
glacier also picks up sediments and moves them to
new places.
Dunes
In sandy deserts and on sandy beaches, the
wind blows the sand into large hills called
dunes. The dunes in a desert or on the beach
are constantly changing due to wind erosion.