Earth Science Textbook Chapter 2 Weathering and Soil

. Chapter Standards the weathering of lo and sol the van oration end deposition ol sediment . As I for this concept a . Students know water running is the dominant process in shaping the landscape . including landscape . Framework Water contributes In two processes that help shine the scape the down of rock into smaller pieces and and the removal ul rock and soil by Students know the number end types at or In ecosystem can support dens on the mourns available end on letters . such as ol end . renge ot temperatures . and soil composition . Framework to support vigorous plant growth , soils must contain sufficient minerals , nitrogen . phosphorus . potassium ) and humus ( decomposed organs excess or alkalinity Sources at ene and differ In amounts . di . and required for their As I been for understanding this . Students know natural energy and material resources . arr , soil , rocks , minerals . petroleum rash water . and forests , and know how to ( them as renewable or nonrenewable . bloom in the State Pam . California . weathering

mun nun and Weathering and Soil formation on the How does the weathering of rock help to reshape Earth topography and form soil ?

Check What You Know Suppose that you carve a model of a mountain in a bar of soap . Then , you leave the model outside in the rain overnight . Based on what you think would happen to the model , predict how rock on Earth surface might change over time .

The images shown here represent some of the key terms in this chapter . You can use this vocabulary skill to help you understand the meaning of some key terms in this chapter . A suffix is a letter or group of letters added to the end of a word to change its meaning and usually its part of speech . the ation or my added to a verb can form a noun that means of or action of . For example , the suffix added to the verb observe forms the noun observation . Example Students in the lab will record their observations . in this chapter , you will learn key terms that have the , and . Sulfur I I Part of I Key Terms Process of . action 01 Conservation , oxidation , rotation Showing continuous Noun or Melting , plowing . smelting , action adjective weathering , Apply It ! Complete the sentences with the correct words . People who electricity are contributing to energy . Rain , snow , and other types of contribute to the ol Earth surface .

' decomposer Chapter Vocabulary Section mineral crystal rock cycle igneous rock sedimentary rock sediment metamorphic rock nonrenewable resource ore smelting Section weathering erosion mechanical weathering abrasion ice wedging chemical weathering oxidation permeable Section , soil natural resources bedrock humus loam soil horizon topsoil subsoil acidic basic litter Section . sod natural resource Dust Bowl soil conservation contour plowing conservation plowing crop rotation . Build Science Vocabulary On ! use Gunter !

to Preview Visuals Before you read your science textbook , it important to take the time to preview the visuals . Visuals are photographs , graphs . tables . diagrams . and illustrations . Visuals contain important information that helps you understand the content . Follow these steps to preview visuals . Read the title , Read labels and captions . Ask yourself questions about the visuals to give yourself a purpose for reading . Preview the illustration titled The Rock Cycle , Figure . Use a graphic organizer like this one to ask questions about the rock cycle . The Rock Cycle Apply Copy the graphic organizer into your notebook . Look carefully at the illustration and write the answer to the question What processes do the arrows show ?

After you read Section I , complete your graphic organizer and revise it as necessary . Before you read Section , create graphic organizers to preview the visuals .

Standards Investigation . Soil for Seeds The process of weathering affects all rocks exposed on surface , Weathering breaks rock into smaller and smaller particles . when the rock particles mix with other ingredients , such as leaves , the mixture is called soil . In this investigation , you will test how soil and other growing materials affect the growth of plants . Your Goal To determine how soil composition affects the growth of bean seeds To complete this investigation , you must compare the particle size , shape , and composition of different growing materials compare how bean seeds grow in several different growing materials determine what type of soil or growing material is best for young bean plants follow the safety guidelines in Appendix A Plan It ! In a group , brainstorm what types of soil and other growing materials you will use in your experiment , What are the different variables that affect the growth of plants ?

How will you measure the growth of your bean plants ?

Plan your experiment and obtain your teacher approval . As you carry out your experiment , observe and record the growth of your plants . Then present your results to your class .

Section Minerals and Rocks Standards Focus ! Students know different a Rock ' ural energy and material resources , Your teacher will give you three different rocks . observe each rock under a hand lens . In your notebook , describe the color or colors that you see in the rocks . Also including air , soil , minerals . petroleum . fresh water . Wildlife , and . and know how to classify In any shapes or patterns in the rocks , Make a sketch of each of your rocks . students know the natural origin . Are your rocks made up of one material or several materials ?

of materials used to make common How can you tell ?

How are the rocks similar ?

How are they different ?

Forming Operational Definitions Sam ! on your observations , how would you define the word rock ?

What are the three major groups oi rock . and how do they form through the rod cycle ?

um , You may think of a golf course as a place covered by smooth . and processed ?

green grass . But that not true of the Devil Golf Course in Death Valley National Park . instead of grass . a jagged crust of KEY 79 salt covers this golf course . The salt forms lacy . and other strange ' When did the salt that the Devil Golf come I rock cycle from ?

About years ago . 21 large lake the area . The . Igneous lake water contained dissolved salt . Over time . the climate sedimentary . drier and the lake slowly dried up . As the water metamorphic rock , the salt was left behind . This salt , the same as ordinary ' WEN ?

table sail . is also called halite . To a geologist . halite is a mineral . ore I smelting Devil Golf Course The fantastic shapes on this dry lake bed in Death Valley National Park , California , are formed mostly of salt crystals .

What Is a Mineral ?

Minerals can be as rare as a precious diamond . Or they can be as common as the halite that makes up the Devils Golf Course . Geologists have more than different minerals . But all of these minerals share certain characteristics . A mineral is a naturally occurring , inorganic solid that on or beneath Earth surface . Almost all minerals have composition . For a substance to he a mineral . it must have all five of these characteristics . Solid Halite occurs naturally in areas once pied by lakes or seas . Halite is inorganic . This means that the mineral did not from materials that were once pan of a living thing . If you pour some halite into your hand , you can see that it is made up of small . solid particles . Crystal Shape Halite also has a crystal shape . in Figure you can see that halite crystals are shaped like cubes . A crystal is a solid made up of particles that line up in a pattern that repeats over and over again . Composition Halite has a composition . This means that it is made up of certain elements in proportions . Halite is made up of one atom of sodium for every atom . Many other als are made up of several elements . A lew minerals are made up of only one element . Copper . silver . gold . and sulfur times occur naturally in this . Each mineral has different properties depending on its chemical composition . For example . minerals differ in color . hardness . and crystal shape . What is a Fawn Mineral crystals Crystals ol the mineral which you know as table shaped like tubes .

Granite and Basalt Granite is made up of large crystals of several minerals . including quartz , mica , and feldspar . The crystals in basalt are too small to be seen without a hand lens . Rock Absorber Here how to lind out if water can soak into track . Using a hand lens . compare samples oi sandstone and shale , Use a balance to measure the mass of each rock . Place the rocks in a pan of water and watch closely . which sample has bubbles escaping ?

Predict which sample will gain mass . Leave the rocks submerged in the pan overnight . The next day , remove the rocks from the pan and the mass of each rock . Drawing How did the masses of the two rocks change after soaking ?

What can you conclude about each rock ?

Rocks and the Rock Cycle Minerals are one of the main building blocks of rock , Rock is the solid material made up of one or more minerals or other substances . Rock makes up Earth hard crust . How do the ferent kinds of rocks form ?

Forces deep inside Earth and at the surface product a slow cycle that builds . destroys . and changes rocks . The rods cycle is a series of processes on and beneath Earth surface that slowly change rocks front one kind to another . Geologists classify rocks into three major groups igneous rock , sedimentary rock , and metamorphic rock . The rocks in each group form through different steps in the melt cycle . Igneous Rodi The rock cycle begins when ten material inside Earth . Then . this material slowly cools and at or beneath the surface . The result is igneous rock ( 16 nee us ) The granite in Figure formed when molten material cooled slowly beneath the surface . Because it cools slowly , granite is made up of large crystals . Other igneous rocks form when molten material erupts onto Earth surface . Basalt forms when molten material cools and hardens on the surface . Because it cools quickly . basalt is made up of very small crystals . Sedimentary Rod The rock cycle continues as melt ( sed uh ' tur ce ) Water and weather cause on Earth surface to break down . forming sediment . Sediment is small . solid pieces of material that come from rocks or living things . Water and wind carry sediment and deposit it in layers . Layers of build up and are squeezed together by their own weight . At the same time . minerals in the rock slowly dis solve in water . These minerals harden and glue the sediment together . Over millions of years . the sediment slowly changes to sedimentary .

away from source by water or wind deposited as loosely peeked squeezed together under . pressure Particles glued together as dissolved minerals harden How Sedimentary Rods Form . Igneous Sedimentary rocks form over millions of years as particles of sediment are deposited and then squeezed and glued together . Relating Cause and Effect What conditions are necessary for sedimentary rocks to farm Some sedimentary rocks . such as sandstone . are made up of particles of other rocks . The remains of plants and also sedimentary rock . For example , limestone forms in the oceans from the shells and skeletons and other mals . type of sedimentary rock forms when minerals dissolved in water form crystals . That how ruck salt , made of the mineral halite . is formed . Gneiss metamorphic . Forming Metamorphic Rod ! As the rock cycle continues . any rock can change into ( met uh lik ) Forces inside Earth can push melts down toward the heat of Earth interior . The deeper a rock is buried . the greater the pressure on that rock . Under great heat and pressure . the in a rock can be changed into other minerals . The rock has become metamorphic rock . For example . heat and pressure . can change granite into gneiss . as shown in Figure . Fanning lock , Heat and pressure change granite ) to a metamorphic rock , gneiss . Cinema 051

The Rock Rocks change continuously through the rock cycle . Interpreting Diagram What process leads to the formation of sediment ?

Go For ( activity Visit Welt Code Pathway of the Cycle As you can see in Figure there are many pathways through the rock cycle . Here is one possible pathway The igneous rock granite fanned beneath the surface of years ago . Then . the forces of mountain building slowly pushed the granite upward . forming a tain . Slowly . water and weather wore away the granite . forming sand . Streams carried the sand to the ocean . Over millions of years , layers of sandy sediment piled up on the ocean . Slowly the sediments were pressed together and cemented to sandstone . a sedimentary rock Over time . the sandstone became deeply buried . Heat and pressure changed the rock texture front gritty to smooth . Over millions of years . the sandstone changed into the metamorphic rock quartzite . Metamorphic rock does not end the rock cycle . For ple . the heat of Earth interior could melt the rock . This molten material could then form new igneous rock .

Using Minerals and Rocks use and rocks in uf . But because and rocks can take millions of years to form . they are considered resources . A resource is one that is not replaced in useful time frame . Uses of Minerals Yuu might be at how products contain . Minerals are the source of gemstones , metals . and other materials used to make many products . such as rubies and throughout the ages . Usually . a is a hard . colorful mineral . are used for jewelry . are also used for mechanical parts and for grinding and polishing . Minerals are also the of such as iron , copper . and silver . aluminum foil . and the Merl used to nitric cars all began as . Matty other are used in foods , and building . Quartz . a mineral found in sand . is used in making glass . salt . mineral . used and . what an gemstones ?

Uses of Rocks history . have Fur rocks . Fur ( ul , out of , il rock . Today , people use rocks for building materials and in industrial processes . durable granite is used in . floors . and kitchen . can lac cul easily into blocks or slabs fur use in buildings . is also used in and steel . Slate splits i . pieces can be for and . Flaunt Gemstones Minerals have many uses . Precious gems like the rubies and emeralds in this ne kIa ( are used in jewelry , I Durable Granite The faces of four presidents were named in granite on Mount Rushmore , South Dakota .

Products From Minerals To understand how minerals must be processed before they are used , compare bauxite and an aluminum can . Examine a piece of the mineral bauxite carefully . Describe its properties , such as color . texture . and hardness , Examine an aluminum can . The metal aluminum comes from bauxite . Compare the properties of the aluminum can with the properties of bauxite . Posing Questions To understand how bauxite is made into a useful material , what questions would you need to ask ?

rib Try Act ity Producing Metals From Ores A rock that a metal or other useful mineral that can be mined and sold at at profit is called an ore . Most do not occur in pure form . metal usually occurs as mineral that is a of that metal and other elements . Copper ( from i ) containing iron and sulfur as well as copper . How is an on made into a finished product ?

To produce metal from an arc , the ore must be mined . or removed from the ground . Then the orc must be processed to extract the metal . Mining Once geologists locate an ore deposit . miners decide how to the orc from the ground . There are three types of mines strip . shaft mines . in strip mining , at ( away ) to ' me . in pit mining . use giant to dig huge pit . Then they retrieve the ore deposits . For on deposits that occur in veins . miners dig shaft mines . Shaft mines often have a . of tunnel that deep into ground . Fault type of mining has effects . For ple . strip mines expose the soil , which can then be blown or away . not he able to grow in it area for . To the land . mine mil during mining , Then they plant grass and ' Smelting Ores must be melted before the metals they tain can be . In the of smelting , an ore is mixed with other substances and than mulled to the useful metal from other elements the on contains . For , iron ores must be smelted to the iron from the and other substances in the ores . Smelling gases and particles of metals into air and water . of these can be harmful to living things . called scrubbers located an exhaust to tho release of harmful substances . gag , smelting ! flaunt Processing Ore Once an ore has been processed in a smelter . the molten metal can be poured into a mold and formed into bars called ingots .

10 Iron Ore Iron ore must be melted to . an at er su stances in ' The mixture is placed in the ED ' ed blast and heated . the other substances in iron are ?

AS bums , co , produce carbon dioxide gas and molten iron . Molten iron sinks to the ' Impurities with the limestone to form slag . The slag and molten iron are . poured otf through taps Section A Target Reading Skill Preview Visuals Review a . Listing List three main uses of minerals and your questions and answers about the rock cycle . two uses of rocks . What are two processes that occur during the , an org ?

rock cycle ?

Summarizing Explain the steps that must take . viewing concepts place before an ore um be made into I product . a . Listing List the characteristics mineral . What does it mean to say that mineral is inorganic ?

is a solid , naturally 111 . ground Many Cull Of household products contain minerals found and animals . will mineral ?

Explain in igneous rock . For example , glass contains . Defining Write a of the rock . quartz , which is hand in granite , Explaining What must happen for any melt one of the following materials and the in the rock cycle to form sedimentary rock ?

products in which it is used garnet . granite . Sequencing Begin with an igneous rock and perlite . pumice . or vermiculite . Explain to explain how it change family members how the rock or mineral more steps in the rock . formed and how it is used . 366 '

( min . Standards Focus . Section Rocks and Weathering Topography is reshaped by the weathering ol null and soil and by the transportation and deposition ol sediment . As a basis for understanding this concept a . Students know water running downhill is the dominant process in shaping the . including California landscape . How do weathering and erosion affect Earth surface ?

what are the causes oi mechanical weathering and chemical weathering ! what determines how last weathering occurs ?

Key Terms I weathering I erosion I I mechanical weathering I abrasion I ice wedging chemical weathering I oxidation I How Fast Can it Fizz ?

Place a antacid tablet in a small beaker . Then grind up a second tablet and place it in another beaker . The whole tablet is a model of solid rock . The tablet is a model of rock fragment . Add 100 warm water to the beaker containing the whole tablet . Then stir with a stirring rod until the tablet dissolves completely . Use a stopwatch to time how long it takes . Add 100 of warm water to the beaker containing the tablet . Then stir until all of the tablet dissolves Time how long . Think It Over Drawing Conclusions Which dissolved faster , the whole antacid tablet or the tablet ?

What variable affected how long it tool each of them to dissolve ?

imagine a hike that lasts for months and covers hundreds of . Each year . many hikers go on such treks . They hike trails that run the length great mountain ranges . For example , the Muir Trail follows the Sierra Nevada . The Sierras extend about 640 kilometers along the eastern side of California . in the cast , the Appalachian Trail follows the Appalachian Mountains . The Appalachians stretch more than kilometers from Alabama to Canada . The two trails cross very different landscapes The Sierras are rocky and sleep . with many peaks rising meters above sea level . The Appalachians rut more rounded and gently ing . and are covered with soil and plants . The highest peaks in the Appalachians are less than half the elevation of the highest peaks in the Sierras . Which mountain range do you think is older ?

The Appalachians formed more than 250 million years ago . The Sierras only within the last ill to 20 million years . The forces that wear down rock on surface have i had much longer to grind down the Appalachians .

Weathering and Erosion The of mountain thrusts ruck up to the of Earth . rock is to . Weathering is the that down rock and other substances at surface . Heat . cold . and ice all In ' So do the oxygen and in the . and thawing , for , can crack rock apart into smaller pieces . Rainwater can dissolve minerals that bind rock together . You do need to go to the to soc . The that wear down mountains also cause bicycles to rust . paint to , tu crack . and to form . The forces of weathering break rocks into smaller and smaller pieces of sediment . Then the forces of carry pieces away . Erosion ( ROH ) is the of sediment by wind . water . ice , or gravity . is reshaped by weathering and erosion . These processes work together continuously to wear down and carry away rocks at Earth surface . and that ( today aim ago . How do know this ?

Geologists un the principle ( youn uh uh un i um ) This principle states that the same that operate today , in the past . arc two kinds uf weathering and weathering . Both types of we act slowly . but over time they break down even the biggest . hardest rocks . Reading what is the difference between weathering and , erosion ! FIGURE 11 Effects of Weathering peaks of the Sierra Nevada ( bottom ) formed within the last to million years . The more gently sloping Appalachians ( top ) have been exposed to weathering for 250 million years . Inferring How can you tell that the Sierra Nevada formed mud more recently than the Appalachians ?

12 Forces of Mechanical Weathering Mechanical weathering affects all the rock on Earth surface . Forming Operational Study the examples of mechanical weathering . Then write a of each term in your lawn words Fueling and when water freezes In a crack in a rock , it expands and makes the crack bigger . The process of ice wedging also widens cracks in sidewalks and causes potholes in streets . Release of Pressure As the surface of a mass of rock erodes . Pressure on the rod is reduced . This release of pressure causes the outside of the rock to crack and flake off like the layers of an onion . This form of weathering is seen In the granite domes of Yosemite National Park in California . Animal Actions Animals that burrow in the moles . gophers . prairie dogs . and same and break apart rocks in the soil . Mechanical Weathering if you hit a rock with a hammer . the rock may break imn pieces . Like a hammer . some forces of weathering break rock into pieces . The type of weathering in which ruck is physically broken into is called mechanical weathering . These smaller pieces of rock have the same composition as the rock they came from . if you have seen rocks that are cracked or split in layers . then you have seen rocks that are weathering Mechanical works slowly . But over very long periods of time , it does mun than wear down rocks . Mechanical weathering eventually wears away whale . 586

Abrasion Sand and other particles that are carried by wind , water , or ice can wear away exposed rock like sandpaper on wood . sand helped shape the shown here . Plant Growth Roots of trees and other plants enter cracks in rocks . As roots , they force the ( farther apart . Over time the roots of even small plants can pry apart cracked rocks . The causes of mechanical weathering include freezing and thawing , release of pressure . plant growth , actions of animals . and abrasion . The abrasion ( uh . refers to the grinding away of rock by ruck particles carried by . ice , wind . or gravity . In cool . most important ( um of ( is the revving and thawing uf . seeps cracks in rocks and then freezes when the temperature drops . expands when it . Ice acts like a wedge that forces things apart . Wedges of ice in rocks widen and deepen cracks . This process is ice wedging . When icy . the water deeper into the cracks . With freezing and thawing , the cracks expand until pieces of rock oil . Mod , i , How does umm For More on Visit Web ( ode ( Gupta !

Chemical Weathering In addition to weathering , another type of weathering attacks rock . Chemical weathering is the process that breaks down rock through chemical changes . The causes of chemical weathering include the action of water , oxygen . carbon dioxide . living organisms , and acid rain . Each rock is made up of one or more minerals . weathering can produce new minerals as it breaks down I ' I ) granite is made up of several minerals . including . quartz , and mica . As a result of weathering , granite eventually changes the feldspar minerals to clay minerals . Chemical weathering creates holes or soft spots in rock , so the rock breaks apart more easily . Chemical and weathering often work together . As mechanical weathering breaks rock into pieces , more surface area becomes exposed to chemical weathering . The Standards activity at the beginning this section increasing the surface area increases the rate ofa chemical reaction . mun Weathering and Surface Area As weathering breaks apart rock . the Surfers area exposed to weathering increases . The total volume of the rock stays the same even though the rock is broken into smaller and smaller pieces . Predicting What will happen to the surface area if each cube is again divided into four cubes ?

If you divide the The surface area of a ti you divide the cube cubes into 64 cubes . cube is equal to times into cubes , the total the total surface area the area of each side . surface area doubles . doubles again 600 Flaunt 14 of Chemical Weathering Acid rain chemically weathered these stone gargoyle on the cathedral of Dam in Paris , France . Water Water is the most important cause of chemical ering . Water weathers rock by dissolving it . When a rock or other substance dissolves in water . it mixes uniformly through out the water to make a solution . Over time , many rocks dissolve in water . Oxygen The oxygen gas in air is an important cause cal weathering . you have ever left a or metal tool side in the rain , then you have seen how oxygen can weather iron . Iron combines with oxygen in the presence of water in ii process called The product of oxidation is rust . Rock that contains iron also oxidizes , or rusts . Rust makes rock soft and crumbly and gives it a red or brown color . Carbon Dioxide Another gas found in air . carbon dioxide , also causes chemical weathering . dioxide dissolves in rainwater and in water that sinks through air pockets in the soil . The result is a weak acid called carbonic acid . Carbonic acid easily weathers rocks such as and limestone . Living Organisms Imagine a seed landing on a rock face . As it sprouts . its roots push into cracks in the rock . the roots grow . they produce weak acids that slowly dissolve rock around the roots . organisms that grow on produce weak adds that chemically weather ruck . Acid Rain Over the past 150 years . people have been burning large amounts of coal . oil . and gas for energy . Burning these fuels can pollute the air with sulfur . carbon . and nitrogen pounds . Such compounds react chemically with the water vapor in clouds . forming acids . These acids mix with raindrops and fall as acid rain . Acid rain causes very rapid chemical weathering . How can plants cause chemical weathering ?

Try Activity Rusting Away Here how you can observe chemical weathering . Moisten some steel wool and place it in a closed container so it will not dry out . Observe the steel wool after a few days . What has happened to it ?

Take a new piece of steel wool and squeeze it between your fingers . Remove the steel wool from the container and squeeze it between your fingers . What happens ?

Wash your hands when you have finished . Predicting It you kept the steel wool moist for a longer time , what would eventually happen to it ?

How is the weathering of steel wool like the weathering of a rock ?

Chantal 061 Hath Algebra and Functions Data which Weathered Faster ?

The graph shows the rate of weathering for two identical pieces of limestone that weathered in different locations . leading Graphs What does the of the graph represent ?

Reading Graphs What does the of the graph represent ?

heading Graphs How much thickness did Stone A lose in years ?

How much thickness did Stone lose in the same period ?

Drawing Conclusions Which stone weathered at a faster rate ?

Inferring Since the two identical pieces of limestone weathered at different rates . what can you infer caused the difference in their rates of weathering ?

Thickness of Stone lost to Weathering ( Rate of Weathering Visitors to New England historic cemeteries may notice a surprising fact . tombstones carved in ( arc weathered and easier to read than marble from the . Why is this so ?

Some kinds of rocks weather more rapidly than others . The most important factors that determine the rate at which weathering occurs are the type of rock and the climate . of Rod The minerals that make up the rock determine how fast it weathers . Rock made of that do not solve in water slowly . Rock made of minerals that dissolve easily in water weathers faster . some rock weathers more easily because it is . uh bull means that a material is full of tiny , connected air spaces that allow water to seep through it . rock chemically at a fast rate . Why ?

As seeps through the spaces in the rock , it dissolves and removes material broken down by weathering . Climate Climate refers to the average weather conditions in an area . Both chemical and mechanical weathering occur faster in wet climates . Rainfall provides the water needed for cal changes as well as for freezing and thawing .

Granite Chemical reactions occur faster at higher temperatures . That is why chemical occurs more quickly where the climate is both hot and wet . Granite . for example , is a very hard rock that forms when molten material cools inside Earth . weathers so slowly in cool climates that it is often used as El building . But in hot and wet climates , granite more rapidly and eventually crumbles ap uL How does rainfall affect the rate of weathering ?

Assessment Section haunt Rock Weathers Faster ?

These two tombstones are about the same age and are in the same cemetery . yet one has weathered much less than the other . Inferring Which type of stone weathers faster . granite or marble , HA Reading Vocabulary Skill ( the sentence with the words i . of ice in rocks widen and deepen cracks in the process of . Reviewing Key Concepts What is weathering ?

lip ?

What is erosion ?

Predicting Over millions of years . how do weathering and erosion change a solid ?

Defining What is chemical weathering ?

and Contrasting Compare and contrast mechanical and chemical weathering . Classify each as chemical or mechanical weathering freezing or thawing , oxidation , water dissolving chemicals in rock . abrasion . acid rain . Identifying What are twu rate of weathering ?

Relating Cause and Effect A granite is placed ( years in region with a cool , dry climate . What would its rate be ?

Explain . 500 Ice in a Straw Demonstrate one type of weathering for your family . Plug one end of a drinking straw with a small piece ol clay . Fill the straw with water . Now plug the top of the straw with clay . Make sure that the clay plugs do not leak . Lay the straw that in the freezer overnight . Remove the straw the next day . What happened to the clay plugs ?

What process produced this result ?

Be sure to dispose of the straw so that no one will use it for drinking . chapter 063 Guided Inquiry , Rock Shake Materials Problem Now will shaking and acid conditions affect the rate at which limestone weathers ?

Skills Focus developing hypotheses . interpreting data . calculating . drawing conclusions containers with caps . 500 Procedure PA . if Using masking tape . label the four containers A , and . Separate the 80 pieces of limestone into four sets of and masking tape . Copy the data table in your notebook . Then place the first 20 pieces of limestone on the balance and record their mass 30 95 07 in the data table . Place the rocks in container marking pen or pencil . Repeat Step for the other sets oi rocks and place them in containers and , Pour 150 of water into container A and container . Put caps on both containers . Four 150 of vinegar into container and container . Flam gradual ! Put caps on both containers cylinder , 250 ' Develop a hypothesis explaining the effect ol weathering on the mass oi the limestone . Predict which will weather more the limestone in water or the limestone in 309 of wage vinegar . Hint Vinegar is an acid . Also develop a hypothesis explaining the effect of shaking on the limestone in containers and Record your hypotheses in your notebook . 300 . Allow the pieces to soak overnight . in vinegar . amid om Tabla . Peru Writ ( at Star Next Day lin Mass in Man A ( water . balance no man . pieces of thin cloth ( paper towels

Dar ! Screw the caps tightly on containers and Shake both containers for 10 to 15 minutes . Make sure that each container is shaken for exactly the same amount of time and at the same intensity . After shaking , set the containers aside . Do not shake containers A and 10 . Open the top of container A . Place one piece of thin cloth over the opening of the container . Carefully pour all of the water out through the cloth into a waste container . Be careful not to let any of the pieces flow out with the water . Dry these pieces carefully and record their mass in your data table . 11 . Next . how much limestone was lost through weathering in container A . Hint Subtract the mass of the limestone pieces remaining on Day from the mass of the pieces on Day . Repeat Steps and 11 for containers , and Analyze and conclude Calculating Calculate the percent change in mass of the 20 pieces for each container . Change in mass 100 hang ! Total mass at start Record the results in the data table . Interpreting Data Do your data show a change in mass of the 20 pieces in each of the four containers ?

Interpreting Data Is there a greater change in total mass for the pieces in one container than for the pieces in another ?

Explain . Drawing Conclusions Did your results support your hypotheses explaining how shaking and acid would affect the weathering ol limestone ?

Explain . Developing if your data showed a greater change in the mass of the pieces in one of the containers . how might this change be explained ?

Drawing Conclusions Based on your data , which variable do you think was more responsible lor breaking down the limestone the vinegar or the shaking ?

Explain . Communicating Write a paragraph that explains why you allowed two of the containers to stand without shaking . and why you were careful to shake the other two containers for the same amount of time . Design an Experiment would your results for this experiment change if you changed the variables ?

For example , you could soak or shake the pieces for a longer time . or test rocks other than limestone . You could also test whether adding more limestone pieces ( 30 rather than 20 In each set ) would make a difference In the outcome . Develop a new hypothesis to explain the effects of changing one of those variables on the rate of weathering . Then design an experiment to test your hypothesis . Have your teacher approve your plan before you begin . ees

Section How Soil Forms 00 Standards Focus Students know different natural energy and material . including air . soil , rocks minerals , petroleum , fresh water . wildlife . and forests . and know how to them as renewable or . what is soil made ol . and how does it form How do scientists ( soils ?

What Is the role of plants and animals in soil Key Terms I soil I bedrock I humus I I loam I soil horizon I topsoil I subsoil I I basic I litter I decomposer What Is Soil ?

Use a toothpick to separate a sample of soil into individual particles . With a hand lens , try to identify the different types of particles in the sample . Wash your hands when you are finished . Write a recipe for the sample of soil , naming each of the ingredients that you think the soil contains . Include what percentage of each ingredient would be needed to make up the soil . Compare your recipe with those of your classmates . Think It Over Forming Operational Definitions on your observations , how would you define the word soil ?

A bare ruck surface docs not look like a could grow . But look more closely . in that hard surface is a small crack . Over many years . and ! ering will slowly enlarge the crack . Rain and wind will bring hits rock . dust . and dry i ' The wind also may carry tiny sci ' i enough , seed will sprout and take root . Then , a few months later , the plant . spot where a plant What Is Soil ?

The crack in the rock seems to have little in common with garden containing thick . rich soil . But soil is what the weathered rock and other I i in the crack have started to become . Soil is the loose , weathered material on surface in which plants can grow . One of the main ingredients of soil from bedrock . Bedrock is the solid layer of rock beneath the soil . Once at the surface . bedrock gradually weathers into smaller and smaller particles that are the basic material of soil .

Soil Composition Soil is more than particles of weathered Soil organic material , water . and air . Together . sand . silt . and clay make up the portion that comes from weathered rock . The decayed organic material in soil is called humus . Humus moo mus is a substance that forms as plant and animal remains decay . helps create spaces in soil for the air and water that plants must have . Humus also contains substances called nutrients . including nitrogen , fur , potassium . Plants need nutrients in order to grow . plants grow . they absorb nutrients from the soil . Fertile soil is rich in the nutrients that plants need to grow . The fertility of soil is measure of how well the soil supports plant growth . Soil that is rich in humus has high fertility . Sandy soil containing little humus has low fertility . Soil Texture Sand feels coarse and grainy . but clay feels smooth and silky . These are differences in texture . Soil texture depends on the size of individual soil particles . The particles of rock in soil are by size . As you ( all see in Figure . the largest soil particles are gravel . The est soil particles are clay . Clay particles are smaller than the period at the end of this sentence . Soil texture is important for plant growth . Soil that is mostly clay has a dense , heavy texture , Home clay soils hold a lot of water . so plants grown in them may drown for lack of air . In contrast . sandy mil has a coarse texture . Water quickly drains through it . so plants may die for lack of water . Soil that is made up about equal parts of clay . sand . and silt is called loam . It has a crumbly texture that holds hoth air and water . Loam is best for growing most types of plants . Composition of Loam Mule 16 Loam . a type of soil , is made up of air , water . and organic matter as well as materials weathered rock . Interpreting Graphs What two materials make up the major portion of this soil ?

Flaunt 17 Soil particles range in size from gravel to day too small to be seen by the unaided eye . The sand . silt , and clay shown here have been enlarged . Soil Clay Silt Sand Gravel and larger Ve For Soll Layers activity Visit Well ( ode From 13 Soil layers Soil horizons in three steps . Inferring which toil horizon is responsible for soil ?

Explain . horizon as bedrock weathers and rock breaks up into soil particles The Process of Soil Formation Soil forms as rock is broken down by weathering and mixes with other materials on the surface . Soil is constantly being formed wherever bedrock is exposed . Soil formation continues over a long period of time . Gradually . soil develops layers called . A soil horizon is a layer of soil that in color and texture from the layers above or below it . If you dug a hole in the ground about half a meter deep . you would see the different soil . Figure shows how soil scientists the soil into three horizon The A horizon is made up of topsoil . at crumbly . dark brown soil that is a mixture of humus . clay . and other minerals . The horizon . often called subsoil , usually consists of clay and other washed down from the A . but little humus . The horizon contains only partly weathered rock . The rate at which soil forms depends on the climate and type of rock . Remember that weathering occurs most rapidly in areas with a . rainy climate . As a result , soil develops more quickly in these areas . contrast , weathering and soil tion place slowly in areas where the climate is cold and dry . Some types of rock weather and form soil faster than others . For example . type of melt formed from the shells and skeletons of things , weathers faster than granite . Thus . soil more quickly from limestone than from granite . a The A horizon develops as horizon develops as plants add organic material rainwater washes clay and to the soil and plant roots minerals from the A horizon weather pieces of rock .

Blue hydrangea ! Pint hydrangea pu Soil types There are thousands of different soil types . Scientists classify the types of soil into groups based on climate , plants , soil composition , and whether the soil is acidic or basic . Fertile soil can form in regions with hot . wet , but rain may wash humus and minerals out of the A . in mountains and polar regions with cold . dry climates . the soil is often very thin . The thickest . most fertile soil forms in climate regions with moderate temperatures and rainfall . The most common plants found in a region are also used to help classify the soil . For example , grassland soils are very different from forest soils . In addition . scientists classify soil by its it is rocky . sandy . or rich in clay . Soils can also be as either acidic or basic . A stance is acidic if it reacts strongly with some metals and changes litmus paper red . A substance is basic if it feels slippery and changes red litmus paper blue . Scientists use the scale , shown in Figure , to how acidic or basic a substance is . A substance with a of is strongly acidic . A substance with it of 14 is strongly basic . A substance with a is neutral . This mums that it is in between acidic and basic . For plains to well , soil must not be mo acidic or ran basic . Must plants grow best if the is between and or slightly acidic to slightly basic . But some soils can have a as low its , which is quite acidic . What does the pit scale measure ?

Flaunt 19 and Basic Soils Soil plants ability to take up nutrients from the soil . it also affects the color of hydrangea . Most basic 10 12 13 14 Red or Blue ?

Vou can use litmus paper to determine whether soil is acidic or . Never taste a substance to test whether it is acidic or basic . Strongly acidic or basic substances are poisonous and can cause burns . Place a small spoonful of soil in a plastic cup . add enough water to the cup hallway , and stir for to seconds . Dip a strip of blue litmus paper in the mixture or soil and water . the color change in the litmus paper . Repeat Steps and using red litmus paper . Inferring What can you infer about the of the soil ?

Chapter ! 065 Living Organisms in Soil If you look closely at soil , you can see that it is teeming with living things . soil organisms malt humus . the material that makes soil fertile . Other soil mix the mil and make spaces in it for air and water . Forming Plants contribute most of the organic remains that form humus As plants shed leaves . they form a loose layer called litter . When plants die . their remains fall to the ground and become part of the litter . Plant roots also die and begin to decay underground Although plant remains are i full of stored nutrients . they are not yet humus . 20 Life in Soil Every cubic meter of soil contains billions of organisms . All organisms that live in soil humus with their remains or wastes This illustration shows some of the organisms typically found in northern forest soil . Relating Cause and Effort Which organisms in the an help all and water to enter the soil ?

Plant roots break up the soil and hold it in place . Many types at i larvae ' are found In the soil .

Humus forum in ii . called . During decomposition , organisms that live in soil tum dead organic humus . Them organisms are called . are the organisms that break the remains of dead organisms into smaller pieces and them with chemicals . Soil ) include fungi , warms , and other ' Fungi are organisms such as molds and rooms . Fungi grow on , and digest . plain . Bacteria arc microscopic that cause decay . Bacteria mack dead organisms and their wastes in ) animals . such as miles and worms . also dci . dead organic material and mix it with the soil . Chi live In dens In ' Chennai ! and search the . decaying organic material . i 13 . lava stems are a major of humus . in colonies In the soil . Earthworm break up hard . i soil . Making it easier for plant roots to spread and for air and hug . me , water to enter the soil . that break down animal and plant remains and wastes . Fungi are that send out long . threads .

Mixing the Soil do most of work of mixing humus with tis in soil . A cut their way through the soil , they carry humus down In the and up to the surface . li ' aim pass out soil cat . as waste . soil is enriched with that plants need to grow . such as nitrogen . burrowing such . moles . up hard . compacted soil and mix humus through it . animals aim Mid nitrogen to mil when produce waste . They add when they div and decay . and burrowing also help to aerate . or mix air into , the soil . Plant , roots the that this adds to 11 the ) ii . Which are most important break up the soul , allowing In an and cy , humus in water . An earthworm eats its own weight in soil every day . Predicting How fertile soil that contains many earthworms likely to be ?

Assessment . Target Reading Skill Preview Visuals Review Identifying in yuur and For 20 , Life in which mil to soil Soil . What twu in the illustration are ?

Describing ( of Reviewing Key . and clinch INT a What would happen to the up of a soil ) HINT . Explaining Huts du ! I ( Sequencing in starting the ( a . Reviewing What main product label for a bag The rah four mil of you , tabet emu 50 an I . Sample , buy , and , 513 how ma mu ' acidic . limit , and haw be Refer to the scale in 19 , 720

Consumer Lab Guided Inquiry , Comparing Soils Materials grams of local soil graph paper ruled with or spacing plastic petri dish or jar lid I plastic spoon and plastic dropper grams of bagged topsoil Problem What are the characteristics of two samples of soil ! Skills Focus observing . inferring . developing hypotheses Procedure obtain a sample of local soil . As you sample , record your observations in your lab notebook . Spread hall of the sample on the graph paper . Spread the soil thinly so that you can see the lines on the paper through the soil . Using the graph paper as a background . estimate the sizes of the particles that make up the soil . Place the rest of the sample in the palm of your hand , rub it between your fingers , and squeeze it . it soft or gritty ?

Does it clump together or ( nimble when you squeeze it ?

Place about half the sample in a plastic petri dish . Using the dropper , add water one drop at a time . Watch how the sample changes . Does any material in the sample ?

As the sample gets wet . do you notice any odor ?

Hint It the wet soil has an odor or contains material that floats . it is likely to contain organic material . Look at some ol the soil under the . Hint Use a toothpick to separate the particles in the soil . Sketch what you see . Label the particles , such as gravel , organic matter , or strangely shaped grains . Repeat Steps with the topsoil . Be sure to record your observations . Clean up and dispose of your samples as directed by your teacher . Wash your hands when you handling the soil . Analyze and conclude . Observing Did you observe any similarities between the local soil sample and the topsoil ?

Any differences ?

Inferring What can you infer about the composition of both types ol soil from the different sizes of their particles ?

From your observations of texture ?

From how the samples changed when water was added ?

Do you think that both types of soil were formed in the same way ?

Explain . Developing Hypotheses Based on your observations and study of the chapter . develop a hypothesis to explain which soil would be better for growing a specific vegetable . Communicating Write a report for consumers that the steps in your analysis of the two soil samples and your results . Be sure to describe what factors you analyzed and give a suggestion for which soil consumers should use for growing flowers and vegetables . Design an Experiment Design an experiment to test the hypothesis that you developed for Question . Be sure to indicate how you would control variables . After you receive your approval . carry out your experiment . Chapter ! 013

00 Section Soil Conservation . Standards Focus oi energy and mate rials ( litter in amounts , distribution . and the required lor their . At a lor understanding this . Students know natural energy material resources . including air , soil , rocks . minerals . petroleum . fresh water . wildlife , and forests . and know how to ( them as renewable or nonrenewable Why is fertile soil ( a nonrenewable resolute ?

How can soil lose its value ?

What are some ways that soil uri be conserved ?

Key Terms I sad I natural resource I Dust Bowl I soil conservation I contour plowing I conservation plowing I ( rap rotation Prairie grasses and How Can You Keep Soil From Washing Away ?

Pour about 500 of soil into a pie plate , forming a pile . Devise a way to keep the soil from washing away when water is poured over it . To protect the pile of soil , you may use ( raft sticks , paper clips . pebbles , modeling clay , strips of paper , or other materials approved by your teacher . After arranging your materials to protect the soil , hold a container filled with 200 of water about 20 above the center of the soil . Slowly pour the water in a stream onto the pile of Kill . Compare your pan oi soil with those of your . think It Over Observing Based on your observations , what do you think is the best way to prevent soil on a slope from washing away ?

Suppose you I ( a west in the mid . of your iourney would have been through vast , open grasslands called prairies . the forests and of the East , the prairies were an sight . 21 person rippled and in the wind like at scat til . The soil was . It was rich with humus because of the tall grass . The thick of tough roots at the surface of the soil in place and held on to ( The ' vast in the ' Today . growing crops such as . and at have replaced the . But prairie soils are still among the in the .

Soil as a Resource resource is anything , in the that use . Soil is one of must natural that on Lind . including ' humans . depends directly or indirectly on soil . Plants depend directly on the will to live and depend on on other that depend on . mil is there is limited . I eh than one eighth til the land on mil that are well suited for farming . Soil is in limited supply because it takes long time to . It mu take ul lor just A tew centimeters at mil to form . The thick . fertile soil of the prairie took many thousands uli years to develop . Because fertile soil is in limited supply and takes a long time to form , it is considered resource . Soil Damage and Loss and change in the environment can affect the mil . The value of soil is reduced when soil loses its fertility and when topsoil is lost due to erosion . Loss of Fertility Soil can he when it loses its ity , Soil that has lost its fertility is said to he . type of mil in large of the South in the Lite 1800 . Soils in which only cotton had been grown were . lett their . ly in the in Alabama . named George ( developed new crop and farming , that helped to mature soil Fertility in the South . were that helped nuke the mil . are . legume small on their that . make nitrogen , an nutrient . in form that um use . FIGURE 22 Restoring Sail Fertility George Washington Carver ( taught new methods of soil conservation . He also farmers to plant peanuts , which helped restore . Applying What nutrient do peanut plants add to the soil ?

13 The Dust Bowl The Dust Bowl ruined in western Oklahoma and parts of the states Wind blew dry ( lES ol soil into great clouds of dust that traveled thousands of kilometers . For links on salt Visit . my Web Code 769 Loss of Topsoil mil ix . water and wind tam quickly carry soil in the of erosion . Plant cover can mil rum . break the of falling min . and plant roots hold the soil together . ind also causes soil loss . Wind is ! likely in areas where farming . not suited to dry . For , wind en led to the Dust an the Great A Soil Loss in the Dust Bowl ' the end of the . settled the Great . The mil til the Great in fertile . But decreases steadily from east to weal the ( also has years when rainfall is scarce . removed the gram from the Great Plains and exposed the soil . In of drought . the nut . turned In dust . and blew ' By almost all of the Great Plains been turned into limits or . Then . long turned the soil un part at the Great to duct . The wind blew the mil east in great , black reached ( New ( Ill ) The was most serious in the southern states . This area , in was called the Dust Bowl . The Dust Bowl helped people appreciate the value of soil . With government port . in the limit and the began to take cure til their land . They adopted that helped save the soil . Some methods were new . Others been practiced for of years . What caused the Dust Bowl !

Soil Conservation Since the Dust Bowl . adopted modern of soil . Soil conservation is the of soil to prevent its destruction . Soil can be conserved through contour plowing , conservation plowing , and crop rotation . In contour plowing , their along the of a slope . This slow the of excess rainfall and prevents it from washing the sail away . In conservation plowing . farmers disturb the soil and its little as . words and stalks of previous are left in the ground to help soil . and hold soil in . This plant at is also called or no till plowing . In crop rotation . plants crops in a year , of plants absorb ' amounts of nutrients train the soil . Some crops , such as and cotton , absorb large amounts of nutrients . The year after plant ing crops . the plants crops that use soil , such as oats , or . The your after that the sows legumes such as ' or beans to restore the . supply . How does conservation plowing , conserve mi ?

Assessment Section FIGURE 24 Soil Methods This farm show of contour plowing and crop rotation . How might plowing effort the amount of topsoil ?

Reading Skill ( following sentence with the correct word ( can soil by crop rotation . Reviewing Key Concepts gun a . Reviewing What is a ?

Explaining Why is fertile soil it ( gulf a . Listing What an um tray in the value can be ?

Explaining haw can be lost . Relating Cause and Effect ' Dust Bowl ?

What is soil ?

Listing ' arc can . mil ?

INT Problem Solving A growing corn wants soil fertility and reduce . What ( lI could . try ?

Explain . Announcement A severe drought in a to produce another Dust Bowl . Write a paragraph about soil conservation to be read as a public service announcement on radio stations . The should Identify the danger of soll loss due to erosion . it should also describe the steps farmers can take to conserve the salt . in ence Gupta !

Chapter imam I Minerals and Racks Key Concepts ! A mineral is a ' ig , solid that forms tin or . all hat crystal . mineral also has a chemical . classify ( ticks min . rock . and metamorphic , The tuck in each form through steps in the rock cycle . Minerals are the of . metals . and mud to ( People rocks for building materials and in Tu metal an . or must he and . Key Terms crystal ' igneous sediment tuck ) are Rocks and Weather ( Key concepts . and erosion ' to wean down ( away th rocks at . Th mugs of . include and thawing . of . plant , animal . and ! The uf the action , oxygen , dioxide , living , anti mini The mint important at which ( arc the type at nick and the . Key Terms erosion ( i ( I ' 780 Study Guide The weathering of helps to reshape Earth topography and ban soil . How Soil Forms Key Concepts ! Soil is a mixture or rock , minerals . tI ) water . and . Soil as broken down by weathering and with run the . Soil i iN . is . intu groups based on climate . plants . soil . and the mil in acidic ut basic . Sonic ! li that nukes soil . Other soil org , mix and in it air and . Key Terms I humus I fertility loam soil acidic I ) Soil Key concepts I mil is in limited and takes long time to form . it is considered . The is it fertility and when is due to erosion . till he plowing . plowing . and crop . Key Terms sud natural I In ! Bowl sail I contour plowing I plowing rotation

El Er HINT HINT Review and Assessment ine For Visit Web Code ' Life in Soil Target Reading Skill Previewing Visuals Complete . What is the subject or this illustration ?

your graphic iii A in Soil with more . What kinds of organisms live underground ?

answers in ' that inn the role of A organising in forming . A . Reviewing Key Ter Choose the letter of the best answer . In the rock , rock that is changed by heat and am ?

a . li ) rock , rock . igneous . The process hill split rock through freezing and is tailed erosion . iv . it . abrasion . clay . sand . and silt is called sod . mil . ull . The horizon consists of . The in sun is by . bedrock . rim is up at roughly equal ui Complete the following so that your answers clearly explain the . Minerals and rocks are resources . One way ruck ) down is mechanical weathering . which i . Ruck is easily because . mil in Ill humus . is hi conservation plowing , conserve mil ' ing in Science Journal Entry You are a farmer on the tall grass prairie in the United States Write a journal entry describing prairie soil . Include the soil composition . how It formed . and how animals helped it develop . Saul Weathering and Soil Formation Chapter 19

Review and Assessment Co 11 What is 41 crystal ?

12 . How are granite and basalt similar ?

How am ) 13 . and ?

14 . the principle ?

15 . Explain how plants can act as oi both and weathering . 16 . What is rule ) i such as and carbon in weathering ?

174 how mil is . Which contains more humus . topsoil or ?

Which has higher ?

role did grass play ! the mil oi the ?

20 . How do plowing and crop rotation to conservation ?

21 . Predicting weathering breaks a rock into pie ( ould this alien the rate at which the rock weathers chemically ?

ally 22 . Comparing and Contrasting ( the layers in the below in terms and . 800 23 . Making Judgments The calcite large , lac ( by a ' Would he us as a gemstone ?

Explain . Applying Use the following information to answer Questions . You two oi soil . Il , moi any i mostly clay . Sandy Soil Clay Sci 24 . Predicting soil sample would low water more quickly ?

Why ! 25 . Designing Experiments ) an mum to test how water through mil . 26 , Posing Questions A farmer wants to grow in om two . questions would the farmer need to answer when to plant the ?

Standards investigation Performance Assessment You arr mid ) to present your data and conclusions about what nil is plants . I low did group results compare with oi the other groups in your class ?

What did you learn from his about soil that help plants to grout ?

How could you improve pour experiment ?

Standards Practice ) Choose the letter of the best answer . use the diagram and your knowledge of science to answer Questions I and . In the cycle . material through the melting of A igneous rock . I sedimentary rock . rock . all above . In the rock cycle diagram . what does the letter represent ?

A melting I cooling and hardening heat and pressure formation which of the following is a mechanical weathering ?

A abrasion I freezing and thawing plant growth above I . A plant grows hes ! in soil with a of . The of this soil can be described as A slightly basic . I neutral . slightly acidic . acidic . at Soil Erosion ! State Tons per Acre per Year Wind Total Erosion Erosion Water i Wyoming New Mexico Use the data table above and your of science to answer Questions and . Of the states listed in the table . which two have the greatest amount of erosion by water ?

A Texas and Tennessee Texas and Hawaii ( I New Mexico and Tennessee and Hawaii . Which state in the table has the greatest soil erosion ?

A Texas Hawaii Tennessee New Mexico , idea . Two rocks . each in a location , have been weathering for the same amount of time . soil has from one rock , but only immature soil has formed from the other . What factors might have caused this in rate of soil formation ?

your answer . include examples of both mechanical and chemical weathering . our