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. The surface of the Earth is always changing. Water and wind, snow and ice, all of these change Water and wind, snow and ice, all of these change the shape of the land.the shape of the land.

Wind can blow soil and small rocks to other places. Wind can blow soil and small rocks to other places. Water can move soil and bits of rocks to new Water can move soil and bits of rocks to new locations. Snow and ice can move down locations. Snow and ice can move down mountains, picking up soil and rocks as it moves.mountains, picking up soil and rocks as it moves.

When any of these things happen, the shape of the When any of these things happen, the shape of the land changes and new landforms are created. This land changes and new landforms are created. This process of moving soil and rocks to new places is process of moving soil and rocks to new places is called called erosion.erosion.

Beaches

Beaches are made of sand and small rocks that Beaches are made of sand and small rocks that have been washed up or blown along the shore.have been washed up or blown along the shore.

The ocean water erodes sand from the bottom The ocean water erodes sand from the bottom of the sea and deposits it on the beach. Rivers of the sea and deposits it on the beach. Rivers erode sediments along their path and drop them erode sediments along their path and drop them as they flow into the ocean.as they flow into the ocean.

The wind is constantly changing the shape of The wind is constantly changing the shape of sand dunes by eroding and moving the sand sand dunes by eroding and moving the sand into new shapes. Water from waves or heavy into new shapes. Water from waves or heavy rain keeps changing the shape of beaches.rain keeps changing the shape of beaches.

Cliffs and RocksCliffs and Rocks

The wind blows, the rain falls, and the waves The wind blows, the rain falls, and the waves crash against the cliffs along the shoreline.crash against the cliffs along the shoreline.

The soil that covers the rocks and cliffs is easily The soil that covers the rocks and cliffs is easily blown away. The ocean waves also pick up the blown away. The ocean waves also pick up the

soil and sand and move them away.soil and sand and move them away.

Erosion, in the form of waves, wind and moving Erosion, in the form of waves, wind and moving sediments, changes the landforms along the sediments, changes the landforms along the

shoreline over a long period of time.shoreline over a long period of time.

CanyonsCanyonsA canyon is a deep valley A canyon is a deep valley

between cliffs, often between cliffs, often carved from the carved from the

landscape by rivers.landscape by rivers.Canyons are formed Canyons are formed when moving water when moving water

erodes and wears away erodes and wears away the sides and bottoms of the sides and bottoms of

a river. The water erodes, a river. The water erodes, or moves, the soil and or moves, the soil and

rocks to new places rocks to new places along its path. along its path.

GlaciersGlaciers

A glacier is like a river of ice. A glacier is like a river of ice. When snow falls and the wind blows high up in the When snow falls and the wind blows high up in the mountains, snow can pile up and turn into ice. The mountains, snow can pile up and turn into ice. The pile of ice becomes so heavy that it starts to move pile of ice becomes so heavy that it starts to move

downhill. This moving ice is called a glacier.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.

DunesDunes

In sandy deserts and on sandy beaches, the In sandy deserts and on sandy beaches, the wind blows the sand into large hills called wind blows the sand into large hills called

dunes. The dunes in a desert or on the beach dunes. The dunes in a desert or on the beach are constantly changing due to wind erosion.are constantly changing due to wind erosion.