The Desert:An Example of Weathering and Erosion

What is a desert?• A landscape or region

• Very low precipitation (less than 10 inches of water per year)

• Sometimes more water evaporates than is received in rain

Is there more than one kind of desert?• There are hot deserts and cold deserts

Cold desertHot desert

How are cold deserts made?• The main form of precipitation in a

cold desert is snow or fog• The snow never melts and thick ice

forms• No plants can grow and few, if any,

animals live here

How are hot deserts made?

The wind acts in three ways:• It weathers the rock and breaks it

into sediments• Sediments are transported by the

wind• Sediments are deposited

somewhere else

How are hot deserts made?• Over millions of years, wind

blows sediments into heaps that grow into dunes

How are deserts made?

• Sometimes the sediments hit very hard rocks and only part of the rock is eroded away, creating rock formations

Some desert facts:

• Deserts cover about 20% to 30% of Earth’s surface

• About 1 billion people live on desert land

More facts:• The Sahara Desert is the largest

hot desert in the world

• Antarctica has the largest cold desert in the world

mesas

Plants (Flora)You probably thought of cactus. Like most desert plants, they …

• Need little water• Are salt-tolerant• Often have few plants, but

much variety

• © Eli SnyderProvided by Free Nature Picture

Animals (Fauna)You probably thought of camels, but the desert has many small animals.

• That includes kangaroo rats, jackrabbits, birds and lizards

• They are out at night because of the daytime heat

What about people?

• People must adapt to the environment.• Hot deserts are REALLY hot• Cold deserts are REALLY cold

• There is difficulty getting water and food

• Often life is nomadic (roaming), yet 1 billion people live in desert regions

Desert Vocabulary• Mesas and buttes are hard rock

landforms that have been eroded away by water

mesa butte

Desert Vocabulary• Salt pan or playa is a lake of salt

water that dries out in the dry season and forms a layer of salt crystal on the ground

Salt pan or playa

Desert Vocabulary• A wadi is a dry river bed. Rain

doesn’t sink into the ground and the result is flash floods.

wadiPhoto by Gila Brand.

flash floodCredit: Shootthedevgru at en.wikipedia

Desert Vocabulary

• A haboob is a thick dust storm or sandstorm that occurs in Africa, Arabia or India

Photo Credit: Stan Celestian, Glendale Community College.

Deserts of the World

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