how does wind change earth's surface?...level a reading coming soon. how does wind change...

Level A reading coming soon.

How Does Wind Change Earth's Surface?

ScienceVocabulary

dust storm

windbreak

Wind is a powerful force that changes Earth'ssurface through weathering, erosion, anddeposition. These three processes can create

H O W D O E S W I N D C H A N G E...

2020 Teachers' Curriculum Institute Level: A

beautiful landscapes and interesting shapes in rock.But wind can also cause damage to plants andhouses. People can design ways to prevent some ofthis damage.

1. Wind CausesWeathering andErosion

This is the surface of a sanddune in Death Valley NationalPark, California. In dry areas,wind is a powerful cause ofweathering and erosion. Herethe wind is eroding sandbetween the plants.

You learned how water changes Earth's surfacethrough weathering, erosion, and deposition. Windalso causes these processes. This is especially truein dry, open areas where strong winds are commonand a lot of rock is exposed.

Think about visiting a dry desert. You observe the


Level: A 2020 Teachers' Curriculum Institute

landscape and see miles of sand all around you.Where did it come from? Sand is made up of smallbits of weathered rocks that are all about the samesize. In deserts, wind often causes weathering byblowing sand and other material against cliffs andlarge rocks. This wears them down and createsmore bits of sand and dust. Over time, the rock isscraped and polished away.

Wind also has the ability to erode. This is especiallytrue where there are not many plants to protect theground. When a gust of wind blows, it picks up sandand other bits of material. It carries these bits withit. Wind can carry pieces the size of sand only forshort distances at a time. But over time it can movethem several kilometers. Tiny pieces like dust canblow thousands of kilometers away.

Wind erosion leads to more weathering. Thematerial that the wind carries helps to weather rockthat it hits, creating more loose material. In thisway, erosion causes more weathering. Andweathering causes more erosion.

2. Wind WeathersRock into NaturalStructures



Arches National Park has rockin many shapes. Weatheringand erosion from wind andgravity helped carve thesepillars from solid rock.

Grains of sand in a desert are small pieces ofevidence of weathering and erosion. Someevidence is much larger, like the Delicate Arch inUtah. It is a large sandstone arch that is 14 meters(almost 46 feet) tall. That is higher than a four-storybuilding! It is shaped like a giant, upsidedown U.How did rock become shaped like this?

The Delicate Arch and other natural arches wereformed because of the dry, windy climate. Later,over long periods of time, strong winds weatheredand eroded the rock that was left. When sand iscarried by a strong wind, it can weather rocks. Onits own, wind cannot cause a lot of damage to rock.But the wind picks up sand and other material. Thesand hits against the rock and breaks off tinypieces. Gravity causes these pieces to fall off,especially when they have been weakened by wind.



It takes a lot of time, but the sand in the wind cancarve large rocks into interesting shapes. It helpedto carve arches out of solid rock!

Wind continues to carve new arches. It also keepscarving old ones. The same process that createdthe arches is slowly working to destroy them. Aswind and sand remove more material, each archkeeps getting thinner. Eventually, weathering willremove so much of their support that gravity willmake these arches fall.

In windy areas, you might see large structures carved from the rock.This one in Arches National Park is called the Delicate Arch.

3. Wind Deposits



Material in New Places

When wind deposits a lot ofsand in one place, it createshills called sand dunes. Windcontinues to move sanddunes even after they areformed. It also createspatterns in sand, like theseripples and waves, that areconstantly changing.

You learned that material eroded by water iseventually deposited in new places. This happenswhen the water slows down. The wind eventuallyslows down, too. Sand and dust that are eroded bywind also get deposited in new places.

Think about the sandy desert again. Windeventually deposits sand after blowing it to newplaces. The sand that you see in the desert wasdeposited and built up over time. Often, an objectsuch as a rock, plant, or building slows down thewind that runs into it. This contributes todeposition.



The size of the pieces of eroded material affectstheir erosion and deposition. Large pieces such aslarge grains of sand are too heavy to be lifted high.Most winds can only carry them across the groundfor a few centimeters or so at a time. Where thesand is carried and dropped by the wind, it canbuild up into hills called sand dunes. Some dunesare 400 meters (about 1,300 feet) tall!

As long as the wind blows, it carries sand over theridges of the dunes and deposits it on the otherside, where the wind is weaker. In this way, thewind causes sand dunes to move one grain at atime. Some dunes can move about 25 meters (82feet) every year. Over time, these hills of sand canmove many kilometers.

4. Wind Can TransportMaterial LongDistances



Wind blows large amounts ofdust from dry areas, like theSahara in Africa. Dust stormsare sometimes so large theycan be seen from space andtransport dust to othercontinents.

In rivers, the force of water sometimes transportslarge rocks and even boulders. Wind cannot movepieces that are nearly this large. But wind canmove some material much farther than any streamor river. The wind lifts small pieces of dust high intothe atmosphere. Some dust blows all the wayaround the world before it settles!

You learned that wind carries sand by bouncing itacross the ground a little bit at a time. Sand grainsare too heavy to be carried higher. But the winderodes lighter pieces of material differently. Dust ismade up of very small pieces of rock, much smallerthan pieces of sand, so it is very light. Wind carriesdust high into the sky.

Think back to the desert. As wind blew across the



ground near Delicate Arch, it eroded the weatheredbits of rock. The distance that these bits wentdepended on their sizes. Larger, heavier pieces ofsand were deposited in the same general area, insand dunes. Other, tiny bits of dust blew high upinto the sky.

Often, these tiny pieces of dust are deposited veryfar away by dust storms. A dust storm occurswhen a strong wind like a weather front blows dustfrom a dry region. When dust storms pass through,they can deposit a layer of dust over everything.They also move large amounts of material.Sometimes the dust is blown thousands ofkilometers.



Sometimes there is so much wind erosion that it creates large duststorms. It can be almost impossible for people and animals inside ofthe dust storm to see.

5. Wind Erosion CanCause DamageWeathering and erosion caused by wind can createbeautiful landscapes like patterns in sand andinteresting arches. But sometimes these processescan cause damage.

Wind erosion damages plants because bits of flyingsand cut their stems and dust covers their leaves.When wind blows away soil, that soil is no longerthere for plants to grow in. So, farms and gardens



can be severely damaged by wind erosion.Buildings can also be damaged when sand blowsagainst them.

During the Dust Bowl years,wind deposition caused a lotof damage on the GreatPlains. Here, a house is partlyburied beneath a giant heap

Wind can cause even more damage in an area thatdoes not have enough plants. During a drought,many plants die due to lack of water, and the soil isleft bare. When wind begins to blow, it can erodeaway the top layer of soil. This happened in theGreat Plains of the United States during the 1930s.For thousands of years, native grasses thereprotected the soil. They kept it in place. Butfarmers tilled up the grasses to plant wheat. Whena drought came, their crops died and exposed thesoil to the wind. The erosion was so bad during thattime it was called the Dust Bowl.

During the Dust Bowl years, wind eroded so muchdry soil it created large dust clouds. Sometimes,



these clouds were so thick they blocked out thesun. Sand was deposited in large heaps that buriedhouses and farming equipment. Millions of peoplechose to leave their homes.

6. Controlling Damagefrom Wind Erosion

People can prevent much ofthe damage caused by winderosion by plantingwindbreaks in open areas.Windbreaks slow down thewind and prevent flying sandand dust from hitting plantsas hard. They can helpprotect houses as well.

Wind erosion can cause serious damage to farms,houses and the environment. The wind blows nomatter what. But people can prevent some of thedamage it causes.

People can learn lessons from events of the past,like the Dust Bowl. It is important not to remove toomany native plants in areas that have long



droughts. People can choose better places to farm.And they can plant crops in ways that hold onto thevaluable topsoil.

People can protect farms and houses from wind bymaking windbreaks along the edges of fields. Awindbreak is a row of plants that is grown in anopen area to help slow down the wind and reduceits harmful effects. The plants can be trees, bushes,or tall grasses planted in a row. Some windbreaksare planted in an L-shape around a field or home onthe sides that face the wind. This creates a wall ofprotection.

Even thin windbreaks slow down the wind that goesthrough. By slowing the wind, they protect plantsfrom drying out as much. And they catch some ofthe flying sand. Thicker windbreaks slow the winddown even more. They stop it completely in thearea right behind them.

You can see how wind changes landscapes. Windweathers rock into smaller pieces, moves it anddeposits it in new areas. Sometimes wind causesdamage, but with good planning most of this canbe prevented.

LESSON SUMMARY

How Does Wind Change Earth's Surface?



1. Wind Causes Weathering and Erosion Windcauses weathering by blowing bits of materialagainst cliffs and large rocks. This wears andbreaks the rock down into sand and dust. Windalso erodes sand and dust.

2. Wind Weathers Rock into Natural StructuresWind can form natural arches and otherlandforms in windy climates. The sand in thewind can carve large rocks into interesting



shapes. Gravity helps shape the rocks too.

3. Wind Deposits Material in New Places The sanderoded by wind is eventually deposited in newplaces. Sand dunes build up where wind depositslarge amounts of sand. The wind keeps movingdunes to new places.

4. Wind Can Transport Material Long DistancesBits of eroded material can travel far and wide.



Wind can carry tiny bits of dust high into the sky.Dust storms can move large amounts of dustthousands of kilometers away.

5. Wind Erosion Can Cause Damage Sand carriedby wind can cause damage to plants andbuildings. Without plants to hold soil in place,wind erodes it. During the Dust Bowl, windcarried sand that ruined homes and farms.



6. Controlling Damage from Wind Erosion Peoplecan prevent damage caused by wind erosion bymaking windbreaks. A windbreak is a row ofplants grown to slow down the wind and reduceits harmful effects.

SUPER SIMPLE SCIENCE

It's a Dust Storm!

The tiniest bits of dirt can be one of the greatestdangers in nature, if you have enough of them.When lifted into the air by wind, they can form duststorms. These sometimes deadly storms are adramatic example of wind erosion in action.

A summer dust stormapproaches Highway 60 inPhoenix, Arizona.

Suppose you are traveling in the desert whilelistening to the radio. Suddenly, an announcer iswarning of an approaching storm. She givesinstructions telling listeners what to do when thestorm hits. But you do not think you will need them.You see clouds, but they seem too far away to be aproblem. Fifteen minutes later, the wind is now



very strong. An enormous cloud of dirt and debris isrushing toward you. How did the danger build up soquickly?

Dust storms can develop quickly. During a duststorm, extremely strong winds carry huge amountsof sand and dust. You might see clear skies onemoment. Then you notice the sky growing darkquickly as a huge wall of dust approaches. The wallof dust can be up to one kilometer (about 3,300feet) high and several kilometers across. Thesestorms can also last several hours or even days!

People cannot do much to prevent dust storms. Butthey can predict them and prepare for them. Topredict dust storms, first scientists need to knowwhere and when they occur.



In places where dust storms occur often, you may hear storm warningsannounced on the radio. You may see warning signs along the roads.

Two things are needed to create a dust storm: windand dirt. Windstorms can occur in many places.However, dust storms usually happen only in ornear deserts. A desert gets very little rain. Withoutmoisture in the ground, surface dirt is loose anddry. Also, fewer plants grow in deserts. As a result,deserts have little plant cover. So, when winds blowthrough a desert, they can easily sweep up theexposed, dry surface material.

Dust storms can occur in any desert region. Most ofthe world's deserts are in North Africa, central Asia,Australia, and southwestern United States. In NorthAfrica, dust storms occur during summer at thesouthern edges of the Sahara deserts. These huge



African dust storms can last for several days andhave even been seen by astronauts in space!

Shorter, stronger types of dust storms usually occurin spring and summer. For example, in the UnitedStates, you may encounter a sudden dust stormwhile driving into the city of Phoenix, Arizona.Phoenix is located in the southwestern U.S. desertregion.

People living in a city like Phoenix listen to the radioor television for storm alerts. They cannot stop astorm from coming. But they can be aware of duststorm predictions and prepare themselves for them.

Keeping Safe in Dust Storms

Scientists know when and where dust stormsnormally occur. They also know what kinds ofweather create dust storms. When all of theconditions for a dust storm happen at once, officialssend out warnings.

So, how can you keep safe during a dust storm? Ofcourse the best thing to do when you hear a stormalert is to take shelter. But dust storms can hit withlittle warning. People may have to act quickly. Theyhave to know what to do to stay safe if they areaway from home.



During a dust storm, dust anddirt fill the air. Dirt clogsmachinery, so traveling bycar or plane is unsafe.

Dust and dirt whirling in the air make breathing andseeing difficult. You should cover your eyes, nose,and mouth immediately. Wrapping a bandanna,your shirt, or other piece of cloth around your noseand mouth will help keep dirt out. Moisten the clotha bit if you have water. You should protect youreyes during dust storms, too. Cover your face withyour arm. Wrap a piece of cloth tightly around yourhead to protect your ears. Knowing these fewsafety tips can help you when a storm suddenlyhits.

Dust storms can also clog up machinery. So, all airtravel stops during dust storms. Car drivers shouldnot enter the storm if they can avoid it. If they arecaught in a dust storm, drivers should pull off theroad and stop.



The layers of rock in Arches National Park were first formed by duststorms and sand storms. Then, wind and water eroded the rock tocreate the arches.

Living with Dust Storms

People cannot prevent dust storms entirely. Butthey can prevent desertification. Desertification iswhat happens when human activities cause land tobecome more desert-like. This process can causedust storms in places they do not normally occur.The Dust Bowl of the 1930s is a famous example ofdesertification. Human activity had removed plantcover from large areas of land. Then little rain fellfor many years. These events together led to duststorms and great amounts of soil erosion.

Dust storms have a long-term effect that can bequite beautiful. Dust storms may occur regularly,



along with sand storms, for an extremely long timein one region. Layers of sand and dirt build upwhere the storms deposit them. When these layersare buried for millions of years, they become newrock. Now, imagine wind and water erosion workingagain. They uncover the rock that ancient duststorms helped create. Wind carves the rock intostunning new shapes, such as the arches in ArchesNational Park in Utah.

If you are ever caught in a dust storm, make sureto take cover until it passes. And, while you safelytake shelter there, think about how you arewitnessing Earth reshape itself!



how does wind change earth's surface?...level a reading coming soon. how does wind change...

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