Earth Science Textbook Chapter 3 Erosion and Deposition

' Standards View Is by the 79 and soil and by an and of As a basis 10 ! this content a . Students know wave ! is the in shaping the . landscape . Framework Surface wile ! glaciers , wind . and Mean waves have all been and continue to be active throughout and lhe rut of an in . students know men and streams or ! systems erode . sediment . ha mum . and banks In and . students know ave systems in the sand by Intel and moved along the was ! by the amen of waves . Students know earthquakes , and floods change human and . Ocean waves slaw ) break down California ( oust . the and sand that make up .

an ration and Deposition What are the forces of erosion and deposition that shape our landscape ?

Check What You Know Suppose that you fill a jar halfway with layers of gravel , sand , and soil . Then you fill the jar with water , over it tightly , and shake for seconds . What effect would shaking the jar have on the soil , sand , and gravel ?

What would happen to them after the shaking stops ?

Explain your answer .

. The images shown here represent some of the key terms in his chapter . You can use this vocabulary skill to help you understand the meaning of some key terms in this chapter . Latin Word Origins Many science words come to English from Latin . In this chapter you will learn the term mass movement . Movement comes from the Latin words meaning to move and meaning the act Movement means the act of moving . Example The movement of wind and water shape Earth surface . movement to move act of the act of moving Learn these Latin words to help you remember the key terms , Latin I Meaning Examples i ' Deposition Apply It ! Review the Latin words and meanings Look at the word and the second meaning of mentum . Predict the meaning of sediment . Revise your definition as you read the chapter .

Chapter Vocabulary Section , sediment deposition mass movement runoff rill gully stream energy flood plain meander oxbow lake alluvial fan load headland beach sand dune deflation loess Section . glacier continental we age valley glacier till moraine Build ( Vocabulary ( as

IQ Sequence Many pans of a science textbook are organized by sequence . Sequence is the order in which a series of events occurs . Sometimes the text uses signal words , such as begin , next , then , and later to show sequence . Look for the sequence of events in the paragraph below . Stream The formation of stream begins when raindrops strike the . Next . the water collects as runoff on the ground and then begins In run downhill . later . this flowing water alum tiny grooves , called rills , to form in the ground surface . A flowchart can help you understand sequence . To make a flowchart , write a description of each step in a box . Place the boxes in order . Stream Formation Raindrops strike ground . Water begins to run downhill . Apply It ! In your notebook , write the fourth step in stream formation . As you read about water erosion in Section complete a flowchart showing the process of stream formation .

um Standards Investigation Changes in the Land What force shaped the rocky cliffs of the California coast ?

For millions of years , powerful ocean waves have been cutting and grinding the coast , The waves carry away broken particles of rock . The waves also pile up boulders , pebbles , and sand to form beaches . In this investigation , you will model how erosion and deposition shape the landscape . Your Goal To make models that show how the forces of erosion and deposition can change a landscape , To complete this investigation you must make a landscape predict how the model would be affected by erosion construct a second model showing how your landscape ' might look after erosion has continued for millions of years follow the safety guidelines in Appendix A Plan It ! To begin , draw a landscape that shows the land before erosion . Then make a list of materials that you will use to build your model . Once your teacher has approved your drawing and your list of materials , build your first model . Next , make a second model to show the effects of erosion . Finally , explain your models to your class .

Section Changing Earth Surface How Does Gravity Affect Materials on a Slope ?

Place a small hoard on your desk . Place a marble on the board and slowly tip one end of the board up slightly . Observe what happens . Place a block of wood on the board . Slowly lift one end at the board and observe the result . Next . cover the board and the wood block with sandpaper and repeat Step . Think It Over , Standards Focus ( A Topography is reshaped by the weathering of rock and soil and by the transportation and tion ol sediment . What processes wear down and build up Earth surface ?

What different types of mass movement ?

Developing Hypotheses How do the results of each step differ ?

yam Develop a hypothesis to explain your observations . sediment I deposition . gum , The ground you stand on is solid . But under certain ' lions , solid earth can quickly change to thick . soupy mud . For example . high rains soaked into the soil and triggered the mudflow in Figure A river of mud raced down the mountainside . burying homes and cars . Several lives were lost . In moments . the moved a huge volume of soil mixed with water and rock downhill . Wearing Down and Building Up A is a spectacular example of erosion . is the process by which natural forces move weathered rock and soil from one place to another . You may haw seen water carrying soil and gravel down a driveway after it rains . Thai an example of erosion . A is a very rapid type of erosion . Other types of move soil and rock more slowly . Gravity . ning water . glaciers . waves . and wind are all causes , or agents . of . in geology , an agent is a force or material that causes a change in Earth surface . I A nosed by heavy rains in San Bernardino . California , brought this ambulance to a stop .

Erosion occurs constantly . even while mountains are forming . When new mountains or form . the cycle of erosion begins all over again . The material moved by erosion is sediment . Sediment may consist of pieces of rock or soil or the lI of plants and animals . Both weathering and erosion produce sediment . Deposition occurs where the agents of erosion deposit . or lay down . sediment . Deposition changes the shape of the land . You may have watched a playing child who picked up several toys . carried them across a room . and then put them down . This child was acting something like an agent of erosion and deposition . Weathering , erosion . and deposition act together in cycle that wears down and builds up Earth surface . This cycle . called the geologic cycle , has continued for billions of years . As a mountain wears down in one place . new landforms build up in other places . Erosion and deposition are at work everywhere on Earth . What is sediment ?

Mass Movement imagine that you are sitting on a bicycle at the top of a hill . With only a slight push . you can coast down the hill . If the slope of the hill is very sleep , you will reach a high speed before reaching the bottom . The force that pulls you downward is gravity . Gravity pulls everything toward the center of Earth . Gravity is the force that moves rock and other materials downhill . Gravity causes mass movement . any one of several processes that move sediment downhill . different types of mass movement include landslides , slump . and creep . Mass movement can be rapid or slow . Erosion wears down mountains and volleys with sediment . Working together . erosion and deposition have almost leveled the land surface . Haunt ! Cycle of Erosion and Deposition Over millions of years . erosion gradually wears away mountains while deposition fills in valleys with sediment . What would happen to the surface ofthe land did not occur ?

Making Models You can make a model of mass movement . Design a plan to model one of the types of mass movement using sand . pebbles , and water . With your approval , make and test your model . How well did your model represent the type of mass movement you chose ?

How could you improve your model ! on ( lE Mass In addition to . types of mass movement landslides . slump , and creep . The la landslide buried 23 homes and killed In people . Making Judgments of mass movement produces the most drastic change in the ( NO Landslides A landslide is a kind of movement that occurs when rock and soil slide rapidly down a steep slope . Some landslides contain huge masses of rock . But many slides contain only a small amount of rock and soil . Some landslides occur where road builders have cut highways through hills or mountains . Figure shows a landslide that struck In ( i . in 2005 . mudflow is the rapid downhill movement of a mixture of water , rock , and soil . The amount of water in a can be as high as 60 percent . occur after heavy rains in a normally dry area . In clay soils with 21 high water content . may occur even on very gentle slopes . Under certain , clay soils suddenly to liquid and begin lo flow . An mi both and landslides , can he very dangerous . Slump you slump your ' the entire upper part of your body drops down . A slump is a type of movement in which a mass of rock and soil rapidly slips down a slope . a landslide . the material in 21 slump moves down in one large mass . It looks as if someone pulled the bottom out from under par ! of the slope . A slump often occurs when of wil hill is rich in clay .

Go For Mass ! Visit Wei Coda Creep ( is the very slow downhill of rock and soil . can even occur on gentle . Creep often results from the and thawing in cracked layers rock beneath soil . Like the ofan hour hand on a clock . is so slow you can barely notice it . But you can see the effects of creep in objects such as rel poles . and ( may these objects at spunky . landscapes by creep may have , look ofa in an park . What is the main difference between a slump and , a landslide ?

section Assessment ix Vocabulary Skill Latin Word Origins the Latin word and . Use what learned In explain of . Evidence of Erosion a rainstorm , take a walk with an ! a . Listing What an agents ?

adult family member around your . Defining In your wards , writ of neighborhood . Look for evidence . of erosion . Try to find areas where ( Predicting Over time , how will erosion and there is loose soil , sand , gravel . or a mountain range ?

lock . Om ' a . Listing art the four ! 99 We find . Relating Cause force causes all types WY ' ma WhI ( areas have the most . Inferring A Fence runs across . Th ' a Fence in and a me he ' he a straight line . What can you ' lo the ' i , Sketch or take photographs of the areas showing evidence erosion .

Guided Inquiry Sand Hills Materials tray ( about 15 Problem What is the relationship between the height and width of a sand hill ?

FOCUS developing hypotheses , interpreting data . predicting Procedure 45 60 ) Begin by observing how gravity causes mass movement . To start , plate the cardboard tube vertically in the center of the tray , Using the spoon , fill the cardboard tube with the dry sand Take ( are not to spill the sand around the outside of the tube , car 03 ' Carefully lift the tube straight that all the sand flows out . As you lift the tube . observe the sand movement . Develop a hypothesis explaining how you think the width of the sand pile is related to its height for different amounts of sand . Empty the sand in the tray back into a container . Then set up your system lor measuring the sand hill . Copy the data table into your lab notebook . dry sand , 500 spoon and ruler pa ' I Height several sheets of white paper masking tape pencil or crayon wooden barbecue skewer . Following Steps through make a new sand hill .

II . Measure and record the sand height and width for Test . See the instructions in the yellow box to help you accurately measure the height and width . Now test what happens when you add more sand to the sand hill . Place your cardboard tube vertically at the center of the sand hill . Be careful not to push the tube down into the sand Using the spoon , fill the tube with sand as before . Carefully raise the tube and observe the sand movement . Measure and record the sand hill height and width for lest . Repeat Steps through 11 at least three more times . After each test , record your results . Be sure to number each test . Analyze and conclude . Graphing Make a graph showing how the sand height and width changed with each test . Hint Use the of the graph for height . Use the of the graph for width . Interpreting Dau What does your graph show about the relationship between the variables . sand hill height and width ?

Drawing Conclusions Does your graph support your hypothesis about the sand height and width ?

Why or why not ?

Developing Hypotheses How would you revise your original hypothesis after examining your data ?

Give reasons for your answer . Predicting Predict what would happen if you continued the experiment for five more tests . Extend your graph with a dashed line to show your prediction . How could you test your prediction ?

Write a paragraph in which you discuss the steps you took to measure your sand hill . Did any problems you had in making your measurements affect your results ?

How did you adjust your measurement technique to solve these problems ?

How to Measure a Sand Hill 14 Cover the bottom of the tray with unlined white paper and tape it firmly in place . Mark off points apart along one side of the paper in the tray . Carefully draw the sand hill outline on the paper . The line should go completely around the base of the hill . Now measure the width of the hill against the marks you made along the edge of the paper . Measure the sand hIll height by inserting a barbecue skewer through its center . Make a mark on the skewer at the top of the hill . Remove the skewer and use the ruler to measure how much of the skewer was buried in the hill . Try not to disturb the sand . Design an Experiment Do you think the use at different materials , such as wet sand or gravel . would produce different results from those using dry sand ?

Make a new hypothesis about the relationship between slope and width in hills made of materials other than dry sand . Design an experiment in which you test how these different materials form hills . Obtain your teacher approval before you try the experiment . for Data sharing Visit Web Code

Section Water Erosion Standards Focus Students know water ning downhill is the dominant pro cess in shaping the landscape . including landscape . students know rivers and streams are dynamic systems that erode . transport sediment . change course . and flood their banks in natural and recurring patterns . What process is responsible for shaping the surface of the land ! what features are formed by water erosion and deposition ! what factors affect a rivers ability to erode and carry sediment ?

Key I runoff I rill I sully I stream I energy I flood plain I meander I oxbow I alluvial fan I dell I load I Home A Sediment in Motion Streams carry sediment in several ways . How Does Moving Water Wear Away Rocks ?

Obtain two bars of soap that are the same size and brand . Open a enough to let the water drip out very slowly . How many drops of water does the faucet release per minute ?

Place one bar of soap in a dry place . Place the other bar of soap under the faucet . Predict the effect of the dripping water droplets on the soap . Let the faucet drip for to minutes . Turn off the faucet and observe both bars of soap . What difference do you observe between them ?

Think It Over Predicting What would the bar of soap under the dripping look like if you left it there for another 10 minutes ?

For an hour ?

How could you speed up the process ?

Slow it down ! Walking in the woods in summer . you hear the racing water ofa stream before you see the stream itself . The water roars as it foams over rock ledges and you reach the stream , you see water by . Sand and pebbles tumble along the tum of the stream . As it swirls . the water also carries twigs . leaves . and bits of soil . In sheltered pools . insects such as water skim the writer calm surface . Beneath the surface . a rainbow trout swims in the clear water . In winter , the stream freezes . Chunks of ice scrap and grind away at the bed and banks . In spring . the stream . Then the how of water may be strong enough to move large rocks . throughout the year . the stream continues to i its small part of Earth surface . Dissolved sediment

A stream causes erosion because of the sediment it carries . Look at . Notice how large sediment moves by rolling ' and sliding along the bottom . Grains of sand or small stones move by bouncing . water can lift and carry sand or Erosion and smaller sediment Water dissolves some sediment completely . Runoff and Erosion Water running downhill is the major of the erosion that has shaped Barth land surface . Erosion by water begins with the splash of rain . Some rainfall sinks into the ground . Some evaporates or taken up by plants . The force of a falling raindrop can loosen and pick up soil particles . As water moves over the land . it carries these particles with it . This moving water is called runoff . Runoff is water that moves over Earth surface . When ' flows in a thin layer over the land . it may cause a type of erosion called sheet erosion . Amount The amount of runoff in an area on five main factors . The factor is the amount of rain an area receives . A second factor is vegetation . Grasses . shrubs , and trees reduce runoff by absorbing water and 25 I ing soil in place . A third factor is the type of soil . Some types of hemmed soils absorb more water than others . A fourth factor is the , 75 an , shape of the land . Land that is steeply sloped has more runoff year . About becomes than land . Finally , a fifth factor is how people use the land . for instance . a paved parking lot absorbs no water . so all ?

a a ' the ram that falls on it becomes runoff . ands , ow , The amount of plant cover in an area affects runoff and runoff remains In the ground ?

sion . Even though deserts have little rainfall . they often have high runoff and erosion because they have few plants In wet arm . runoff and erosion may be low because there are more plants to protect the soil . ems ' precipitation is 75 an 21 eventually to oceans as runoff Less than remains In the ground ODS

Raindrops Falling Find out how the force of falling raindrops affects soil . Fill a petri dish with textured soil to a depth oi about . Make sure the soil has a smooth flat surface . but do not pack it firmly in the dish . Place the dish in the center of a newspaper . Fill a dropper with water . Squeeze a large water drop from a height of in onto the of the soil . Repeat times . Use a meter stick to measure the the soil splashed from the dish . Record your observations . Repeat Steps through this time from a height ol Drawing Conclusions Which test produced the greater amount of erosion ?

Why ?

From . mils . and Gullies Water flowing across the land runs together to form rills , gullies , and streams . Predicting What will happen to the land between the gullies as they grow wider ?

Rills and Because of gravity . runoff and the material it contains move downhill . During sheet erosion . runoff forms tiny grooves in the soil called rills . As many rills into one another . they grow larger . forming . A gully is a large groove , or channel , in the soil that carries runoff after a storm . As water through gullies , it moves soil and rocks with it , thus enlarging the through erosion . Gullies tain water only after it rains . Streams and Rivers Gullies join together to form a larger channel called a stream . A mum is a channel along which water is continually clown a slope . Unlike streams rarely dry up . Small streams are also called creeks or brooks . As streams flow together , they form larger and larger bodies oi water . A large is often called a river . Erosion by Rivers As a river from the mountains to the sea . the river forms a variety of features . Through erosion . a river creates valleys . waterfalls . plains , meanders , and lakes . How does a river cause erosion ?

A river water has energy . Energy is the ability to do work or cause change . When energy does work , Ihe energy is transferred from one object to another . Sheet erosion All along river . the energy don work , A river always moving lrom the mountains to the sea . At Go online lime , grind and chip ) at the of a the riverbed . deepening and widening the river channel . Far More an Rivers often on mountain . Near its Vim ' Web Code , a river is flowing and generally straight . course Thu slopes along the river crude ) The result is drop . valley . Waterfalls may occur where river meets an area of rock that very hard and slowly . The river over this rock and then rock . you can see in Figure the softer rock wean faster than the harder . where the collar rock was removed . ul rough water called rapids ( occur where a river over hard rock . Flood Plain lower down on its course , river usually over more gently sloping land . Thu spreads out and , a wide river valley . The . wide amt river 21 plain . river its plain it its banks during . On wide , valley walls ( from the river . A river may cut into ing the river course through flood plain . How a Waterfall Form A forms where a flat layer of tough rock lies over a layer 01 softer rock that erodes easily . When the softer rock erodes . pie ( es of the harder rock above break off , creating the sharp drop . Harder rock layers eventually break ' Softer rod layers erode first . Rapids are areas of below the falls where water rushes over .

noun Meander and Oxbow lakes Erosion often forms meanders and oxbow lakes where a river winds its flood plain . small obstacle creates a slight bend in the river . water erodes the outer edge of a , the bend become bigger . Deposition occurs along the inner edge . the meander becomes more curved The river breaks through and takes a new ( curse . Oxbow lake oxbow lake remains NO Meander A river often ( it through easily eroded rock or sediment . A is a bend in of a river . As the river winds from side to side . it tends to the outer bank and deposit sediment on the inner bank of a bend . Uver time . the meander becomes and . Because of the sediment river carries . it can a very wide plain . Along this part of a river course . its channel is deep and wide . are common . The southern stretch of the River ( river that ( on a wide , gently flood plain . Oxbow Lakes Sometimes a river forms a feature called an oxbow lake . As Figure shows . an oxbow is a that has been cul oil from . oxbow may form when a . During the Hood , high a straighten mutt . As the waters lull . sediments dam up the ends of it ( has ) an oxbow lake , Randi , How does an oxbow lake form ?

Deposits by Rivers As moves , it carries ' with it . time slows down . it drops , or deposits . some of sediment . As water slows down . tine particles full to the river bed . Larger quit rolling and sliding . Deposition creates landforms such as alluvial fans and deltas . It can add soil to river plain . II on ( you can these and other shaped by rivers and streams .

Alluvial Fans Where a stream out of ii steep , mountain valley . the stream suddenly becomes wider and shallower . slows . iii an alluvial fan . An alluvial fan is it wide , sloping at when leaves a range . As its suggests . this deposit is can set an fan in . Deltas A river ends its when it flows into a still ' such as an ocean or lake . Because the river water is no hill . I ' slows . At this point , the in the ' drops to the bottom . where a river into an ocean or lake builds up at call A delta . Deltas can be a variety ( if shapes . The delta til the Nile River in is like a triangle . The delta of the Mix ' in Figure , isan example of it type of delta called loot delta . Soil on Flood Plains Deposition can also occur during . Then heavy rains or mun to rise above its banks and out aver its plain . the water . it as new soil . of new plain is when ( river li i ' can grow in the soil at a plain . The soil is also for growing crops . nude , How can a be Flaunt Alluvial Fan This alluvial fan in Death Valley , California . was deposits by streams from the mountains . haul 10 Delta This satellite image shows the pan of the Mississippi River delta where the rivet empties into the Gulf of Mexico . In 2005 , parts of the delta and the of New Orleans were flooded as a result ol Hurricane Katrina . Observing What happens to the Mississippi River as it flows through its delta ?

Can you find the river ! channel ?

input ! 999 Waterfalls and Rapids and rapids are where the river passes over harder rock . Many ( rivers have and rapids . Rapids are Ii river flows through the My and men a deep , valley As the river flows . it cuts the valley deeper . Many rivers in the Sierra Nevada have . valleys . where have carved the valley wail Examples the and river A flood plain where the river gamer of erosion widens its valley rather than deepening IL The San Joaquin and Sacramento rivers both have vest flood plains . Meander Where the river flow was easily eroded sediment . its bends from side to side in a series of meanders . The Sacramento River has both meanders and oxbow lakes where it Central Valley . Sand carried downstream by the river spreads along the coast to form beaches .

mums The course ofa Rivet lhe slope and size of a rivet . as well as the sediment it carries . determine how a river shapes the land . Which result from erosion ?

from deposition ?

The river receives water and sediment from a smaller river or stream that flows into it . Oxbow lake An lake is a meander cut from the river by deposition of sediment . Valley ' As the river approaches sea level , it meanders more and develops a wider valley and broader flood main . Bluffs Erosion forms called bluffs along the edge ot a plain . Dene Where the Into the ocean . it deposits sediment . a delta . In California . the Sacramento River and the San Joaquin River join to a large with many channels .

Erosion and Sediment Load Gentler . we The power of at river to cause erosion and carry ment depends on several factors . CA river is I dynamic system A river slope . volume of flow , and the shape of in all how fast the river and how much sediment it can erode . The amount of sediment that a river carries is its loud . A river carries more and larger particles of sediment . When a river slows down , it drops its sediment load . The larger particles of The Slope of I ment are deposited first . A rivers slope is usually greatest eat 19 ! SOME I Slope Generally , if a river slope increases . the approaches its mouth . its slope lessens . water speed also increases . A river slope is the amount the river drops toward sea level over a given distance . river speed increases , its sediment load and power to erode may increase . of Flow A river is the volume of water that moves past a point on the river in given time . Volume of flow is also called . As more water flows through a river , its speed . During at . the increased volume of water helps the river to cut more deeply into its banks and bed . The power to erode increases greatly . A flooding river can carry huge amounts . soil . and other sediments . It may move giant boulders as if thev were pebbles . Functions I on the Move The velocity , or speed . of a stream affects the size of the sediment particles the stream can carry . Study the graph , then answer the questions below . Reading Graphs What variable is shown on the of the graph ?

Reading Graphs What variable is shown on the of the graph ?

Data What is the speed at which a stream moves small pebbles ?

Large boulders ?

A stream speed increases to about 600 per second during a flood . What are the largest particles the stream can move ?

Developing Hypotheses Write a hypothesis that states the relationship between a stream ' speed and the size of sediment it can move . Sediment a Stream Can Carry Diameter of ( Clay particles Shape Whether it river flows in straight line or a curved line the way it erodes and deposits sediment . Where a river in a straight line . the water faster near the center of the river than along its sides . Deposition occurs along the sides of the river . when the water moves more slowly . if a river curves . the water moves fastest along the outside of the curve . There . the river tends to cut into its bank . causing meat 13 Stream Erosion and Deposition A river erodes sediment from its banks on the outside curve and deposits sediment on the inside . Relating Cause and Effect Why does a river deposit sediment an the inside of a curve ?

erosion . Sediment is deposited on the inside curve . where the water speed is slowest . You can see this process in Figure . checkpoint does the water fastest ?

Section Target Reading Skill Look at the illustration showing Meander and Oxbow Lakes . Write down in order the steps that occur to an oxbow lake . Reviewing Key Concepts ' a . Reviewing What is the maior agent of erosion on Earth surface ?

List these in order tributary . stream . rill . gully . runoff . river . Predicting Where would he more likely to form a field with plowed soil and no plants . or a lick ! covered with grass ?

a . Listing What are live features than erosion forms along a river ?

in . listing What are three that result from deposition river ?

Relating and Ethel Why does a delta often where a river meets the ocean ?

HINT El Assessment Where I strum curves . In what pan of the stream identifying What three factors affect how fast it river ?

la . Interpreting Diagrams Study Figure 13 above . Over time , what will happen to the river hank at point ?

its its . grains , and paragraph deposited . in Science we i Guided Inquiry , Streams in Action ' Problem How do rivers and streams erode the land ?

Skills Focus making models . observing plastic container Creating Streams Over Time . Your teacher will give you a plastic tub containing earth that has been soaked with water . Place the tub on a level surface . CAUTION Dry diatomaceous earth produces dust that may be Irritating if inhaled . To keep the earth from drying out , spray it lightly with water . up . One end of the tub will contain more earth . Use a block 59 of wood to raise this end of the tub . Place the cup at the upper end oi the slope with the notches pointing wood blocks about to the left and right . thick . Press the cup firmly down into the earth to secure its position . Start the dripper ( see Step in the yellow box on the opposite page ) Allow the water to drip to the right onto the diatomaceous earth . Allow the dripper to drip tor minutes . When you need to add more water , be careful not to disturb the dripper . Observe the flow of water and the changes it makes . Use the hand lens to look closely at the stream bed . plastic stirrers , an long . After minutes . remove the dripper . small holes each , In your lab notebook , draw a picture of the resulting ma stream and label it ' 10 . Now the dripper to the left side of the cup . Restart the dripper and allow hand lens , scissors . and ?

I clock or watch 11 . Draw a picture and label it I blue food coloring and liquid detergent Changing the Angle of Slope . Remove the cup from the stream table . Save the stream bed on the right side of the tub . Using the bowl of the spoon . smooth out the diatomaceous earth on the left side . To increase the angle of slope of your stream table , raise the end of the tub another . In your lab notebook . predict the effects of increasing the angle of slope . Replace the cup and restart the dripper , placing it in the notch on the left side of the cup . Allow the dripper to drip for minutes . Notice any changes in the new stream bed . After minutes , remove the dripper . Draw the bed in your lab notebook . Label it Increased . Follow your teacher instructions for up alter this activity . Wash your hands when you have finished , Analyze and conclude . Observing Compare the stream with the stream . How did the length of time that the water flowed affect erosion along the stream bed ?

Drawing Conclusions Were your predictions about the effects of increasing the angle of slope correct ?

Explain your answer . Observing What happened to the eroded material that was carried downstream ?

Making Models What features of streams were you able to observe using your model ?

How could you modify the model to observe additional features ?

Variables What other variables besides time and angle of slope might affect the way rivers and streams erode the land ?

Communicating Describe an example of water erosion that you have seen , such as water flowing down a hillside or street after a heavy rain . Include in your answer details such as the slope of the land , the color of the water , and the effects of the erosion . Making the . Insert the wire into one of the two holes in a plastic stirrer . The ends of the wire should protrude from the stirrer . Gently bend the stirrer into a shape . Be careful not to make any sharp bends . This is the dripper . With scissors , carefully cut two small notches on opposite sides of the top of the foam cup . Fill the cup to just below the notches with water colored with two drops of blue food coloring . Add more food coloring later as you add more water to the cup . Add one drop of detergent to keep air bubbles out of the dripper and increase flow . To start the dripper , fill it with water . Then quickly tip it and place it in one of the notches in the cup , as shown above . Adjust the rate of the dripper to about drips per second . Hint Bend the dripper into more of a shape to increase flow . Lessen the curve to reduce flow . Design an Experiment Design an experiment in which you use your model to measure how the amount of sediment carried by a river changes as the volume of flow of the river Increases . Obtain your approval before you try the experiment . chapter 9105

Science and . as ' In 2005 , water from Hurricane Katrina flooded New Orleans , Lo na . The city lies on the Mississippi plain . High levees were supposed to protect the city . But several levees failed , and flood waters poured in . At least ten million American households are located on plains . The cost ! damage has been growing . Communities along rivers want to limit the cost of flooding . They also want to protect people and buildings . The Issues I Should the Government Insure People Against Flood Damage ?

The United States government offers insurance to households in flood plains . The insurance pays part oi the cost ol repairs after a flood . However , government flood insurance is available only to towns and cities that take steps to reduce damage . Cities must allow new building only on high ground . In addition , the insurance will not pay to rebuild homes that are badly damaged by flood water . Instead . these people must use the money to find a home somewhere else . Critics say that government insurance just encourages development in areas that flood . Another problem with the Insurance is cost . It is very expensive , so most people who live in plains don ! buy the government insurance . Supporters say government insurance rewards towns and cities that rules to control building on flood plains . Over time . this approach would mean fewer homes and other buildings on less damage from . 106

in 200 , from Katrina to the rooftops of many New Orleans houses Thousands of people were stranded arid had to be by twat much at New Orleans alter the historic hy How Much of the Flood Plain Should Be Protected ! Government flood insurance is available only in areas where scientists expect flooding at least once in 100 years . But such figures are just estimates . Three floods occurred in only 12 years in a government flood area near Sacramento , California Should the Government Say Where People can Live ?

The and severity of flooding is an important in decisions . Sometimes , no construction on a flood plain is advisable . Some programs of flood control forbid all new building . other programs may also encourage people to move to safer areas . The 1997 flood on the Red River in Grand Forks . North Dakota . is one example . After the flood , the city of Grand Forks offered to buy all the damaged buildings near the river The city wants to build high walls of earth to protect the rest of the town The Grand Forks plan might prevent future damage , but is it fair ?

Supporters say that since the government has to pay for flood damage , it has the right to make people leave flood plains . of such plans say that people should be free to live where they want . even in risky areas . Who should decide that no new houses can be built in a certain local , state . or federal government ?

Some believe scientists should make the decision . Identify the Problem In your own words , describe the controversy surrounding flood plains and housing . Analyze the Options List several steps that could be taken to reduce the damage done to buildings in flood plains For each step , include who would benefit from the step and who would pay the costs . Find a Solution Your town has to decide what to do about a neighborhood damaged by the worst flood in 50 years Write a speech that argues for your solution . Gu For More on protecting homes in flood plains ' Visit Web Code

Section Waves and Wind Standards Focus 909 water , glaciers . wind . and ocean waves have all been and to be active throughout California and the rest at the world in ing landscapes . Students know beaches are dynamic systems in the sand is supplied by rivers and moved along the toast by the action of waves . what gives waves their energy ?

How do waves shape a toast ?

what are the causes and effects ! wind erosion ?

Key Terms I headland I beach I longshore drift I spit I sand dune I deflation I loess A wave nears the shore . What Is Sand Made Of ?

Collect a spoonful of sand from each of two different beaches . Examine the tirst sample of beach sand with a hand lens . Record the properties of the sand grains , for example . color and shape . Hold a magnet close to the sand . Are any ot the sand grains magnetic ?

Examine the second sample and repeat Step . How do the two samples compare ?

Think It Over Posing Questions What questions do you need to answer to understand beach sand ?

Use what you know about erosion and deposition to help you think of questions . Ocean waves contain a great deal of energy . Created by ocean winds . they carry energy the Ocean . Acting like drills or buzz saws . the waves erode the solid rock of the coast into and caves . also carry sediment that forms features such as beaches . How Waves The energy in waves comes from wind that blows across the water surface . As the wind makes contact with the water . some of its energy transfer to the water . Large ocean waves are result of powerful storms lair out at sea . But ordinary breezes can produce waves in lakes or small ponds . The that water picks up from the wind causes water particles to move up and down as goes But the water particles themselves do move forward . A wave changes as it approaches land . in deep writer . a wave only affects the water near the surface . But as it approaches shallow water . the wave begins to drag on the bottom . The between the wave and the bottom causes the wave to slow down . Now the water actually does move forward with the wave . This water provides the force that shapes the land along the shoreline .

incoming waves Erosion waves bend as they approach the shore ( left ) and focus their energy on headlands , Waves carved this sea arch ( right ) in Baja California . Predicting what will happen to the headlands ?

Erosion by Waves Waves are the force of erosion along coasts . including the California coast . shape the coast through erosion by breaking down rock and sand and other sediment . How waves Erode One way waves the land is by impact large waves can hit rocks along the shore with great force , This energy in waves can break apart ruck . Over time , waves can make small cracks larger . Eventually , the waves cause pieces of rock to break ull . also erode by abrasion . Recall that abrasion is the wearing away of rock by a grinding action . As a wave approaches shallow water . it picks up sediment . including sand and gravel . This sediment is carried forward by the wave . When the wave hits land . the sediment wears away rock like sandpaper wearing away wood . Wei MI Waves coming to shore gradually change direction . The change in ' occurs as parts of a wave begin to drag on the bottom . Notice how the waves in Figure change direction as they approach the shore . The energy of these waves is concentrated on . A headland is a part shore sticks out into the ocean . Headlands starts out from the coast because they are made harder rock that resists erosion by the waves . But . over time . waves erode the and awn out the shoreline . in

sea suck ! standing when sea arch collapses FIGURE 15 The Changing Coast ( left ) and deposition ( right ) a variety oi along a toast . You can often see these features along rocky pans of the California coast . Predicting What will eventually happen to the sea arch ?

110 an Formed as wave action hollows out the diff Landforms Created by Wave Erosion when waves hit a steep , rocky coast . they strike the area again and again . Think of an ax striking the trunk of tree . The cut gets bigger and deeper with each ( if the . Finally the tree falls . In a similar way , ocean waves the base til the land along sleep coast . Where the rock is stiller . the waves erode the land faster . Over lime lhe ' erode hollow area in the rock called sea cave . Eventually . waves erode the base of at much that the rock ' The result is a dill . You can we an example of such ( I cliff in Figure IS . feature created by ' erosion is sea arch . A sea arch when waves crude a layer of I ( that lies a layer ruck . llan arch , the might be ) sea stack . a pillar of rock rising above the water . Over a long period of time . what men do waves a ?

have on a steep . mast ?

, Features leach Formed is wave pile up and along the shore ! Formed as drift deposits sand Deposits by Waves Waves shape a coast when they deposit sediment . forming coastal features such as beaches , spits . sandbars . and harrier beaches . Deposition occurs when slow down , Causing the water to its . This is similar Lu tho deposition that occurs on in river delta when the river slows clown and drops it load . Beaches As waves reach the shore , they drop the sediment they carry . a beach . A beach is an area of along a . The sediment beaches is usually . Most sand comes from rivers that ' particles of rock into the ocean . are dynamic . are constantly changing as supply sand and the action of moves along the coast . The sediment beach moves down the bench after it has ' usually hit the at an angle instead of straight on . angled waves rent that run parallel to the coastline . As ' repeatedly hit the . some of the moves down the beach with the current . in A process called drift . Calculating A sandy ( cast erodes at a rate of per year . But a storm can erode an additional from the share . If 12 severe storms occur during a period , how much the coast etude ?

If you wish , you may use an electronic calculator to find the answer . 111 FIGURE 16 Spits This aerial photograph shows how drift can carry sand and deposit it to form a spit . What feature along the coast do you think reused the spit to form ?

Explain . Flaunt Sand Dunes In California . areas of sand dunes are found in parts of the Mojave Desert . Spits One result of drift is the mation of a spit . A spit is a beach that projects like a out into the water . Spits form as a result of deposition by drift . Spits occur where a headland or other drift . or where the coast turns abruptly . Sandbar and Barrier Beaches Incoming waves carrying sand may build up sandbars . long ridges of sand parallel to the shore . A barrier beach is similar to a . A barrier beach when storm waves pile up large amounts of sand above sea level forming at long . narrow island parallel to the coast . Barrier beaches are found in many places along the of the United States . such as the Outer Banks of North Carolina . In California . can he found at the mouths of rivers and hays . Examples range from Silver Strand Beach in San Diego to the barrier beach that shelters Humboldt Ba ) in northern California . People have built homes on many of these barrier beaches . But the storm waves that build up the beaches can also wash them away . Barrier beach communities must he prepared for the damage that hurricanes and other storms can . Erosion by Wind Imagine a landscape made almost entirely of sand . A sand dune is a deposit of sand . Over of years . wind sweeps sand a desert . piling up huge , dunes . Wind by itself is the weakest agent of erosion . Water . waves . moving ice . and even mass movement have more effect on the land . Yet wind can be a powerful force in shaping the land in areas where there are few plants to hold the soil in place . For example . few plants grow in deserts , so wind can easily move the grains of dry sand . Wind causes erosion by and abrasion .

Fine particles carried through ) particles skip ' or bounce , larger particles slide or roll . I Deflation The wily that wind muses erosion is by dell . tion . Geologists as the process by which wind removes surface . When wind blows over the land , it picks up the smallest particles of sediment . This sediment is made of bits of clay silt . The stronger the wind . the larger the particles that it can pick up . Slightly heavier particles . such as sand . might skip or for at short distance . But sand soon falls back to the ground . Strong winds can even roll heavier sediment over the ground . Figure 18 shows how wind erodes by . does not usually have great on land , ever . in of the Great Plains in the ) caused the loss of about I meter of topsoil in iust a few . deserts . can create an area of rock desert . shown in Figure 19 . There . wind has blown away the smaller sediment . All that remains are that are too heavy to he moved . Areas are common in ( Ur ser ' Where there is slight depression in the ground . ion can produce a hollow called . Abrasion Abrasion by can polish rock , but it causes little erosion . At one time , geologists thought that the sediment carried by wind out the stone shapes seen in deserts . But now evidence shows that most desert landforms are the result of and water erosion . Where would you be most likely to see evidence of wind erosion ?

Erosion Wind erosion moves sediment particles of different sizes in the three ways shown at the left . Comparing and Contrasting Compare the movement of sediment by wind with the movement of sediment by water in Figure earlier In the . How are the processes similar ?

How are they different ?

FIGURE 19 Desert Pavement wind erosion formed this desert pavement in the Arizona desert . sand may polish and shape individual stones . 0113 dunes form where the wind usually blows in the same direction . dunes form where the wind direction changes frequently . Wind direction 20 Movement of Sand Dunes Wind direction helps determine the shape and size of sand dunes . Section Vocabulary Skill Latin Word Origins Use what you learned to complete the following sentence . A in which wind down surface materials is called ( Reviewing Key Concepts ' in ocean waves ?

erosion along a coast ?

Assessment a . Explaining What is the source energy . Describing How does an ocean wave change when it reaches shallow water ?

Inferring Does an way possess potential energy or kinetic energy ?

Explain . Identifying two results of wave Deposition by Wind All the sediment picked up by wind eventually falls to the ground . This happens wind slows down or some obstacle . such as a boulder or a clump of grass . traps the blown sand sediment . erosion and deposition may sand dunes and deposits . Sand can be seen on and in deserts sediment has built up . Sand Dunes Sand dunes come in many shapes and . Some are long , with parallel ridges . while others are . They can also he very small or very sand ( in China have grown to heights of 500 meters . Sand dunes move over time . Little by little . the sand shifts with the wind from one side of the to . This process is shown in Figure in ( sand dunes occur along the coast ' supplied sand to bays . Examples include the dunes near Bay . Bay . and San Diego Bay . Areas of sand dunes can also be found in Death Valley and the Mojave . Loos Deposits that is than sand , such as of clay and silt , is sometimes deposited in layers far from its source . This line , sediment is ) Large deposits are found in central China and in United States . helps to form fertile soil . Many al IS with thick deposits are valuable farmlands . writing . Reviewing What arc two of wind erosion ?

to . Identifying What are two types of that result from wind deposition ?

Predicting in II desert , soil containing a mixture and small is exposed to wind erosion . Over time . how would the land surface change ?

Writing in Science that . Listing What am formed by Write I paragraph in which wave ?

processes that formed Ill ! barrier belch . Also INT Relating Cause and Ellen Beginning with it the source of sand , explain how ! spit forms .

Section Glaciers ards Focus Framework Surface water . glaciers . wind , and ocean waves have all been and continue to be active throughout and the rest oi the world in shop ing landscapes . what are the two kind at glaciers ?

How does a valley glacier form and move ?

How do glaciers cause erosion and deposition ?

Key Terms glacier continental glacier ice age valley glacier plucking till moraine kettle the Hubbard Glacier in Think it Over Inferring Based on your observations , how do you think moving ice could change the of the land ?

How Do Glaciers Reshape the Land ?

Fill the container with water . Remove the block of ice from . Rub the ice . sand side down . over a bar of soap . Observe what Put some sand in a small plastic container . and place the container in freezer until the water turns to ice . the container . Hold the ice with a paper towel . happens to the surface of the soap . You on boat trip near the coast ul Al . You by vast evergreen forests and . Then . as your boat rounds a point of land . you see an amazing sight . A great mass of like a river rows of mountains . Suddenly you hear a noise like thunder , Where the ice the seat . a giant chunk of ice breaks off and plunges into the ' the pilot st your boat around the iceberg and toward the mass of ice . it lowers over your boat . You see that it is made up of solid ice that is deep blue and green as well as white . What is this river of ice ?

10 Ice in North America heart 21 continental Glaciers During the last ire age , a continental glacier covered most of North America . How Glaciers Form and Move Geologists a glacier as any large mass of ice that moves slowly over land . There are two kinds of and valley glaciers . Continental Glaciers A continental glacier is a glacier that covers much ofa continent or large island . A continental glacier can cover millions of square kilometers . Today . continental glaciers cover about 10 percent of Earth land . They cover Antarctica and most of Greenland . The glacier covering Antarctica is over kilometers thick ! Continental glaciers can in all directions Continental glaciers spread out much as pancake batter spreads out in a frying pan . Many times in the past . continental glaciers have covered larger parts of Earth surface . These times are known as . Beginning about million years ago . continental advanced and retreated . or melted back . several times . They ! about years ago Valley Glaciers A valley glacier is a long . narrow glacier that forms when snow and up high in a mountain ley . The sides of mountains keep these glaciers from spreading out in all directions . Instead . they usually move down valleys that have already been cut by rivers . Valley glaciers are found on many high mountains . Although they are much smaller than continental glaciers . valley glaciers can be tens of meters long . In California . small valley glaciers occur on many of the highest peaks in the Sierra Nevada and on Mount Shasta . High in mountain valleys . temperatures seldom rise above freezing . Snow builds up year after year . The weight of more and more snow compacts the snow at the bottom into ice . Glaciers can form only in an area where more snow falls than melts . Once the depth of snow and ice readies more than 30 to 40 meters , gravity begins to pull the glacier downhill Valley glaciers flow at a rate of a few centimeters to few meters per day . But sometimes a valley glacier slides down more quickly in what is called a surge . A surging glacier can as much as kilometers per year . on what type at are valley glaciers nuan . LE found ?

How Glaciers Shape the Land The movement of at glacier changes the land beneath it . Although glaciers work slowly , they are a major force of sion . The two processes glaciers erode the land are plucking and abrasion . Glacial Erosion As a glacier over the land . it picks up rocks in a process called plucking . Beneath glacier . the weight of the ice can break rocks apart . These ruck fragments freeze to the bottom of the glacier . hen the glacier moves . it carries the rocks with it . Figure 22 shows plucking by a glacier . Many rocks remain on the bottom of the glacier . and the glacier drags them across the land . This process . called abrasion . gauges and scratches the bedrock . You can see the results of erosion by glaciers in Figure 22 . In a similar way . glacial erosion formed Valley in the Sierra Nevada . 22 Glacial Erosion in tracks in this landscape ?

Bedrock Bolero Form As a glacier moves ( left ) plucking breaks pieces of bedrock from the ground . Erosion by glaciers can carve a mountain peak into a sharp horn ( below ) and grind out a valley to form a valley . What other changes did the glacier produce After Have Melted 0117

. Min 13 Glacial Landforms As glaciers advance and retreat . they sculpt the landscape by erosion and deposition . Classifying these glacial features according to whether they result from erosion or deposition drumlin , ham , clique . moraine . valley . For Links on glaciers Welt ( ode Ill Item When awe away the sides of mountain . the mutt is I ham . I sharpened peak . Cirque A clique Is a hollow eroded by I glacier . An arete is a sharp ridge separating two . Glacial Deposition A glacier gathers a huge amount of rock and soil as it erodes the land in its path . I glacier melts . it deposits the sediment it eroded from the land . creating various . These landforms remain for thousands of years after the glacier has melted . The mixture of sediments that a glacier deposits directly on the surface is called till . Till is made up of particles of many sizes . Clay , silt . sand , gravel , and boulders can all he found in till . The till deposited at the edges of a glacier forms a ridge called a moraine . A terminal moraine is the ridge of till at the farthest point reached by a glacier . A moraine that formed at the end of the last ice age extends across part of Yosemite Valley in California . Retreating glaciers also create features . A is a small depression that forms when a chunk of ice is left in glacial till . When the ice melts . the kettle remains . The continental glacier of the last ice age left behind many kettles Kettles often till with water , forming small lakes called kettle lakes . Small lakes also form in the hollow eroded by a glacier at the base of a high peak . There are many of these lakes in Sierra Nevada .

my leave behind large lakes in long basins . ix . A glacier scoops out a valley . A moraine form where a glacier mounds or ridges of till . A in lung mound direction ofthe glacier now . A kettle lake forms when a depression left In by melting ke fills with water . Section target Reading Skill Sequence Valley Glaciers under the heading How Glaciers Form and Move . Then organize the in a called How a Valley Glacier . the first box write . Snow builds up . the next steps in the . Reviewing Key Concepts lulu . Defining What is glacier ?

Defining What is ! Valley glacier ?

Comparing and Contrasting How are types of glaciers ?

How are they different ?

I . Reviewing How does a glacier form ?

Explaining Haw does a glacier ?

Relating Cause and Effect Why does the snow that forms 41 glacier change to ice ?

033 LE 11 Assessment Heading . Writing What are two ways in which II glaciers surface ?

Describing deposition occur ?

Writing in Science , Chapter Study Guide ' Having water . wind . and ice are foxes that shape our landscape I Changing Earth Surface Key Concepts Weathering . and deposition act in . that war and builds up . causes mass movement . including , and . Key Terms sediment gravity Water Erosion Key Concepts . water is the til the that has ' land , Through . a , falls , plains . and lakes . Deposition creates alluvial fans and deltas . It can add mil Ina riv plain . A river slope . and the its all how river and much it uni . Key Terms ru nu IT I ill gu lly rea itt flood plain 120 lulu alluvial lan delta Waves and wind Key Concepts . Th energy in waves comes from mud that ' across Water . I shape the by breaking down rock and transporting sand and . shape a mat when they deposit ) Ill , such as ! sand lurk . and beaches . Wind by deflation and . Wind and may form sand dunes and deposits . Key Terms sand dune drift spit Glaciers Key Concepts There are two ( of and glaciers . can only in an area snow fall than melts . Once the depth of snow ' 30 In 40 . gravity begins pull the glacier downhill . Th um by which glacier land are plucking and . When glacier melts . it deposits the sediment il from laud . various . Key glacier plucking continental glacier till it moraine glacier kettle

Review and Assessment ' For Visit . Web Code Target Reading Skill Sequence Complete a I . Strum . mass and by ! glacier is called Stream Formation mad . Raindrops strike ground . pick up hi called I . a . drift . Key Complete the following sentences so that choose me lane of me be your answers clearly explain the key terms . Miter ' slow INT . The ' I ' I . lo ) or Ind down vin mi Shim is are called ' till . Rain that falls to the can form . I . desert . is , i . sediment . 10 . A , It ' may meander , which Is . ul materials , inning head , at . ewe to tho . drift . which is Id My . 12 . Out when A glacier . moraine . As lI . I I . ta ' in . thatyou have just returned . rill . from a visit an a limestone me , such as . Mammoth Cave in . Write an article . ur visit to the cave . Include how INT . her a , occurs he ' I a . 111 the muddle . along inside of . mde . developed . it . along the outside or the curve . as miter up . INT . Flu erosion ol lav wind I ) Erosion and Deposition ( plucking . Chapter ! 0121

Review and Assessment Checking Concepts 13 . What ( arc hy of gravity ?

14 . Beginning with rain hitting the . describe the hy which . 15 . I lint ( an Lin ?

16 , do river slope and ul the rivers load ?

17 . the ut ' the , river the ?

Explain . Jun ?

19 . What arc ?

20 . How docs held lake form ?

Thin 21 . Comparing and Contrasting and contrast landslides and . 11 . Applying Concepts ) a that tan ' timid plain . 23 . Making Judgments A salesperson yuur ' a new house right till a for very little money . Why might your imitate tu buy this ?

24 . Relating Cause and What the features labeled . and ( I in the below ?

Explain . 25 . Inferring You sandy along , did mind from ?

26 . Problem Solving you are A , cuuld you use to tell if it is or 121 Applying Skills Use the table below to answer Questions . The how 11 ' and land ( Volume of Flow ( cubic meters ! I second ) January 200 Sediment load it . February I 27 . Graphing Make ( MIC graph with the mi and ul on the . Make graph with load on the ( your graphs . the ( and load the greatest ?

The lowest ?

28 . Developing Hypotheses graphs to a hy the of . 29 , Relating Cause and may have in the in April tu must the lal ) in volume of and ( Standards Investigation Performance Assessment ( yuu an to ul erosion lu your to your that formed as the result of erosion . Predict how the change as .

. Choose the latter oi the but . I . What is the slow , downhill mass movement of rock and soil . mused by gravity ?

A landslide I creep runoff it glacier . Which statement best describes the process that forms strain ?

A Sheet erosion digs a deep channel . I Tiny rills enlarge to form gullies . which join to form a stream . Small enlarge to form rills , which deepen to form a stream . Water flows down a valley . A meander hall is cut off from the main course of a river becomes am A kettle lake . I delta . oxbow lake . alluvial Fan . As it stream from a mountainous area to a area . what happens to the size of the sediment the stream carries ?

A The sin does not change . I The sediment size carried by the stream ' i . The sediment size carried by the stream decreases , The stream drops all the sediment it was carrying . Which of the following is an of longshore drift ?

A Deep deposits of loess are . I A meander forms in a river . A builds up at A river mouth . Beach sand moves along a coastline . Standards Practice at Use the diagram below and your knowledge of science to answer Questions and . Speed of Stream Faster Slower . What is the erosional feature in the diagram ?

A a meander I it delta it plain an alluvial fan . In the diagram . where is the speed of the stream the greatest ?

A at I at at at I . Scientists determine that a certain plain will probably have at severe two or three times in a hundred years . The best type of land use for the plain would be A shopping center . I homes and schools . and forest . tall buildings . Describe how gravity is involved in the erosion of Earth surface by mass movement . running water , and glaciers . Be sure to first explain what erosion is . chapter