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CONTENTSINTRODUCTION

GeologyandGeography

CHAPTER1PlateTectonicsShapeOurLandandSea

CHAPTER2MountainRanges

CHAPTER3VolcanoesandEarthquakes!

CHAPTER4ThePlains

CHAPTER5Climate

CHAPTER6Rivers

CHAPTER7Ecosystems

CHAPTER8TheGreatLakes

GLOSSARY

RESOURCES

INDEX

T

INTRODUCTION

GEOLOGY&GEOGRAPHYheGreat Plains andMountainWest form the heartland of theUnitedStates. This area in the middle of the country has land rippling with

wheatandcorn. Ithas towering,majesticmountains.And ithas themostdestructivetornadoesintheworld.

TheGreatPlainsandMountainWestalsocontainsomeofournation’sgreatestnaturalwonders.MaybeyoulivenearthemightyMississippiRiver.MaybeyouhavevisitedtheGreatLakes,orexploredYellowstoneNationalPark.

WhydotheplainsoftheMidwestspreadoutflatlikeapancake?HowdidtheRockyMountains,whichrisesohigh,formrightnexttotheseplains?EventhoughthecentralpartoftheNorthAmericancontinentdoesn’thaveexplodingvolcanoes, lots of changes have happened there over billions and billions of

years.

Inthisbook,you’ll learnabout thegeologyandphysicalgeographyof theGreatPlainsandMountainWest.You’llreadabouttheforcesthathaveshapedthe region’s mountains, plains, rivers, weather, and ecosystems. And you’lldiscoversomeinterestingfactsaboutthearea.

Did you know that earthquakes in Missouri have caused waves in theMississippiRivertotravelupstream?Orthat theGreatLakesholdonefifthofthefreshwateroftheentireworld?Asyoureadthroughthisbook,you’llgettowork on a lot of exciting experiments and projects. They will help youunderstandnewconcepts,likehowafloodhappens.

WORDSTOKNOWplains:aflatexpanseofland.

theMidwest: anothername for theGreatPlains in themiddleoftheUnitedStates.

geology: thescientific studyof thehistoryandphysicalnatureoftheearth.

geography: the study of the earth and its features, especially theshapeoftheland,andtheeffectofhumanactivity.

ecosystem:acommunityofplantsandanimalslivinginthesameareaandrelyingoneachothertosurvive.

freshwater:waterthatisnotsalty.

GEOLOGY:MORETHANJUSTROCKSMostpeoplethinkofgeologyasthestudyofrocks.Geologycertainlyincludes

that,butit’smuchmore.Whenyoulookatarock,youcandescribeitscolorandshape.Butwhatisevenmoreinterestingishowthatrockformedandhowitgotto itspresent location.That involves seeing thebigpicture—thepictureof thewholeearth.

Geologyisthescientificstudyofthehistoryandphysicalnatureoftheearth.Itexplainshowthecolorandshapeofarockgivescluestothehistory

ofthatrock.

Geologyinvolvesthehugemovementsoftheearth’scrust.Italsoinvolvesthesystemsof theatmosphereandhydrosphere,becauseairandwateraffectthebreakdownandformationofrocks.AndthegeologyoftheGreatPlainsandMountainWestispartofthegeologicstoryofournationandtheearth.

GEOGRAPHY:MORETHANJUSTSTATESANDCAPITALS

Justasgeologyisaboutmorethanjustrocks,geographyisaboutmorethanjuststatesandtheircapitals.Theseareimportant,butgeographytellsabiggerstory.

There are two parts to geography. Physical geography includes things likemountains, rivers, climate, and the shape of the land. The second part ofgeography,calledculturalgeography, ishowpeople interactwith the land.Anexample of cultural geography would be how farming changes the soil of aregion. Cultural geography includes things like population, agriculture, andrecreation. If you live in theRockyMountains youmight spend yourwintersskiingbecausetherearesteepslopeswithplentyofsnow.

WORDSTOKNOWcrust:thethick,outerlayeroftheearth.

atmosphere:theairsurroundingtheearth.

hydrosphere: the earth’s water, including oceans, rivers, lakes,glaciers,andwatervaporintheair.

climate:theaverageweatherofanareaoveralongperiodoftime.

ThisbookcoversthestatesofMontana,Wyoming,Colorado,NorthDakota,SouthDakota,Nebraska,Kansas,Minnesota,Iowa,Missouri,Wisconsin,

Illinois,Michigan,Indiana,andOhio.

Lookatthemapandyou’llseethatthisisahugearearightinthemiddleofthe United States. Are you ready to take a ride on a riverboat down theMississippiRiver,whirlaround insidea tornado,andclimbdown intoa silvermine!Let’sgo!

T

CHAPTER1

PLATETECTONICS

SHAPEOURLANDANDSEAheGreatPlains stretchout flat forhundredsofmiles.Then thePlainsrise sharply into the rugged, high Rocky Mountains. How did these

regionsformandwhydotheylooksodifferentfromeachother?

Tounderstandthedrivingforcebehindtheformationofthedifferentlandscapesin the Great Plains and Mountain West, you first need to understand platetectonics.

WORDSTOKNOWplate tectonics: the theory thatdescribeshowplatesmoveacrossthe earth and interact with each other to produce earthquakes,volcanoes,andmountains.

WORDSTOKNOWvolcano:avent intheearth’ssurfacethroughwhichmagma,ash,

andgaseserupt.

earthquake:asuddenmovementintheouterlayeroftheearth.Itreleasesstressbuiltupfromthemotionoftheearth’splates.

erosion: the wearing away and carrying off of materials on theearth’ssurface.

brittle: describes a solid that breakswhen put under pressure.Abladeofgrasswillbend,butadrytwigisbrittleandwillbreak.

mantle: themiddle layerof theearth.Theuppermantle, togetherwiththecrust,formsthelithosphere.

dense:tightlypacked.

lithosphere:therigidouterlayeroftheearththatincludesthecrustandtheuppermantle.

Plate tectonics is the theory that theouter layerof the earth ismadeupofinterconnectedplatesthatmovearound.Togetherwiththeheatfromthesun,thepowerful forces inside the earth shape every landscape and ecosystem on thesurface of the earth.Volcanoes,mountains, valleys, plains, earthquakes, anderosion all happenwhen andwhere they do because of themovement of theearth’splates.Tounderstandplatetectonics,firstlet’slookinsidetheearth.

APEEKINSIDETheearthmaylooksolidandmotionless,butmuchofitisliquid.Itconsistsofthreelayers.

Thecrustisthethin,outerlayeroftheearth.Thisisthelayerthatwewalkon.It’ssolidbutbrittle,whichmeansthatitbreakswhenunderpressure.

Themantleisthelayerbelowthecrust.Itishotteranddenserherebecausethe temperature and pressure inside the earth increase the deeper you go. Theuppermantleisbrittleandsolid.Together,thecrustandtheuppermantleformthelithosphere,orthehardouterlayeroftheearth.

The lithosphere is broken into plates. Below the plates is a layer of themantle called the asthenosphere. It is partiallymolten and can flow slowlywithoutbreaking—abitlikeSillyPutty.

Thecoreisthecenteroftheearth.Itisextremelydenseandmadeupofironandnickel.There’saninnercore,whichissolidbecausethepressureissogreat,andanoutercore,whichisliquid.

WORDSTOKNOWasthenosphere: the semi-molten middle layer of the earth thatincludes the lower mantle. Much of the asthenosphere flowsslowly,likeSillyPutty.

molten:meltedbyheattoformaliquid.

core: the center of the earth, composed of the metals iron andnickel. The core has two parts—a solid inner core, and a liquid

outercore.

oceanic:inorfromtheocean.

continental:relatingtotheearth’slargelandmasses.

Thecoreisalmostashotasthesun—about9,000degreesFahrenheit(5,000degreesCelsius)!

DIDYOUKNOW?Youmighthaveheardoftheearth’splatesbeingsectionsoftheearth’scrust.That’spartlycorrect.Thetectonicplatesaremadeofthecrustandtheuppermantle,whichtogetherarecalledthelithosphere.Butmost people just call it the crust because it’seasiertoremember.

PLATES:THEEARTH’SPUZZLEThe hard outer layer of the earth, the lithosphere, is broken up into about 12largesections,calledplates.Therearealsoseveralsmallerplates.Theplatesfittogether like a jigsaw puzzle. Most of the plates are part oceanic and partcontinental.Forexample,theNorthAmericanPlateincludesnearlyallofNorthAmericaandthewesternhalfoftheAtlanticOcean.

Theplatesareinconstantslowmotion!That’sbecausethelayer justunderthe plates—the asthenosphere—is very hot. The heat causes themolten rocksthere, called magma, to move around in huge rotating currents calledconvection cells. These convection cells move the plates above, which arefloatinglikeraftsonthehotgoobelow.Theplatesalsohelpthemselvestomovealong.Theolderpartofaplateiscolderanddenserthanthenewerpart.Whenitsinks into themantle it pulls the rest of the platewith it and keeps the cycle

going. Plates move somewhere between 1 to 6 inches per year (2 to 15centimeters).

WORDSTOKNOWmagma:partiallymeltedrockbelowthesurfaceoftheearth.

current:aconstantlymovingmassofliquid.

divergent boundary: where two plates are moving in oppositedirections, sometimes called a rift zone. New crust forms at riftzonesfromthemagmapushingthroughthecrust.

rifting:whenthelithospheresplitsapart.

ONTHEEDGEVolcanoes and earthquakes don’t just happen anywhere. They’re arranged inpatterns.Forexample,therearelotsofvolcanoesaroundtherimofthePacificOcean,buttherearenoneinKansas.That’sbecausemostoftheactionhappenswhereoneplatemeetsanother.Thisiscalledaplateboundary.Therearethreedifferentkindsofplateboundaries.

Divergent plate boundaries are where two plates move apart from eachother.Theydothisbecausethemagmabeneathispushingupward.Thiscausesrifting.Thehotgoopushesoutandsolidifiestoformnewrocks.Nearlyallofthe earth’snewcrust formsat divergentboundaries.AnexampleofnewcrustcanbefoundatCratersoftheMoonNationalMonumentinIdaho.

Convergentplateboundaries arewhere twoplatescollide.Whathappensdependsonwhethertheplatesareoceanicorcontinental.Whenanoceanicplatecollideswith a continental plate, volcanoes form.Because the oceanic plate isdenserthanthecontinentalplate,itslidesunderneaththecontinentalplate.This

iscalledsubduction.

WORDSTOKNOWconvergentboundary:wheretwoplatescometogether.

subduction: when one tectonic plate slides underneath anothertectonicplate.

As the subductedoceanicplate sinks lower, itsweightpulls the restof theplatealongaswell.Thesinkingplateencountersalotofheatandpressure.Thiscauses the plate to release hot gas and steam,which rises andmelts the rockabove.Themeltedrock,themagma,alsorisestothesurface,creatingvolcanoes.Itcanalsocompressthecontinent,causingthecrusttobuckle.

TheRockyMountainsformedwhenoceaniccrustsubductedbeneaththeNorthAmericanPlateandcausedthecrusttobuckle.

Ifacontinentalplatecollideswithanothercontinentalplate,theybothbuckleupwards, formingmountains. That’swhat is happening nowwhere the IndianPlateandtheEurasianPlatearecolliding.TheresultistheHimalayaMountains,whichincludethehighestmountainintheworld,Mt.Everest.

Oceanic-ContinentalConvergance

WORDSTOKNOWtransformboundary:wheretwoplatesslideagainsteachother.

fault:acrackintheouterlayeroftheearth.

hotspot:anareainthemiddleofaplate,wherehotmagmarisestothesurface.

tectonic:relatingtotheforcesthatproducemovementandchangesintheearth’scrust.

craton:thestable,centralpartofacontinent.

igneousrock:rockthatformsfromcoolingmagma.

metamorphic rock: rock that has been transformed by heat orpressureorbothintonewrock,whilestayingsolid.

Transformplateboundariesarewhere twoplatesgrindagainsteachotherastheymovesidebysideinoppositedirections.Astheplatesmovepasteachothertheysometimessuddenlyslip.Thiscreatesabiglurch,orearthquake.

OntheWestCoast,thefamousSanAndreasFaultinCaliforniaispartofatransformboundarybetweentheNorthAmericanandPacificPlates.ThisiswhyCaliforniahassomanyearthquakes.

Hotspots areotherareasof stronggeologicactivity,but theyaren’ton theedgeofplates.Thesearevolcanicregionsthatusuallyoccurinthemiddleofaplate. They exist because extremely hot magma, probably from deep in themantle,makes itsway to the surface. There is a hotspot beneathYellowstone

NationalPark,whereWyoming,Idaho,andMontanameet.

DIDYOUKNOW?The oldest rocks in the United States are found in northernMinnesota in the Minnesota River Valley and northernMichigan.Theyarebetween3.5and3.7billionyearsold.Theoldest rocks onEarth are in northernCanada, and are over 4billionyearsold.

GIANTCONVEYORBELTThemovementoftheplatesactsabit likeagiant,wideconveyorbelt.Thisconveyorbeltislikeaflatescalator,usedtomovepeopleor things across a long space. At divergent boundaries, magmapushestheplatesapart,cools,andformsnewcrust.

The lithosphere is like a rigid board, though, and as two platesmove apart, the other end of each plate collides with morelithosphere. At the collision point, one plate is subducted, orpushedunder,andmelts.Solithosphereiscreatedononeend,and

destroyedonanother. Just likeconveyorbelts,or the stairsonanescalator, lithosphere appears on one end and disappears on theotherend.

TECTONICHISTORYOFTHEGREATPLAINSANDMOUNTAINWEST

Thisareahasa long tectonichistory.Over2½billionyearsago, smallbitsofcontinentalandoceaniccrustcollidedandstucktogetherovertime.Thisprocessformed the central part ofNorthAmerica, called the craton.Mountainswereuplifted and volcanoes formed. The rocks in the craton are igneous andmetamorphic.Theyformedathighpressuresandtemperaturesdeepwithinthecrust,atleast10milesbeneaththesurface(16kilometers).

The mountains that formed were probably as high as the HimalayaMountainsoftoday.Thisveryoldpartofthecratonincludesthecentralsectionof Canada and the northern Midwest of the United States including parts ofMinnesota,Wisconsin,andMichigan.

NorthAmerica2BillionYearsAgo

TheNorth American continent continued to grow as other pieces of crustwere added onto the southern edge of the craton.These newer pieces of cruststretchfromwhatisnowArizonatoMissouri.

WORDSTOKNOWbasin:alowareashapedlikeabowl.

sediment:looserockparticlessuchassandorclay.

sedimentary rock: rock formed from the compression ofsediments, the remains of plants and animals, or from theevaporationofseawater.

geologist:ascientistwhostudiestheearthanditsmovements.

Then, a little over a billion years ago, the continent tried to rift apart. Itstarted in an area inwhat is nowKansas, extending throughNebraska, Iowa,Minnesota, Wisconsin, and Michigan. The rifting stopped, perhaps becauseNorth America began colliding with another continent along its eastern edge.ButtheriftcreatedabasinwhereLakeSuperioristoday.

Later,erosionremovedlayersofrocksinthemountainsovermanymillionsofyears.Onlythe“roots”oftheancientmountainsremained,leavinglandthatwasaflatrollingplain.Whenashallowinlandseacoveredmuchofthecraton,the seas left sand, mud, and seashells. These sediments formed into a thincoveringofsedimentaryrocksovertheolderrocks.

NorthAmerica1.8-1.65BillionYearsAgo

Around80millionyearsago, theplatesweremovingagain.Usually,whenan oceanic plate collideswith a continental plate, volcanoes form close to theboundary.

Butthistime,asalargeoceanicplatewaspushingundertheNorthAmericanPlate, theRockyMountains formed hundreds ofmiles inland.Whywas thereactivitysofarfromtheedgeofaplate?Geologists thinkthattheoceanicplatesubductedatashallowangle.Thiscausedthecrusttocompressthecratoninthemiddleofthecontinent,pushingupmassesofold,hardrockstoformtheRocky

Mountains.

AstheRockieswerepushedupward,theywerealsoerodingatthesametime.

Sandandmuderodedandwasdepositedontothelowlandstotheeastofthemountains.Ashfromvolcanoeseruptingwascarriedeastbythewind.AllofthissedimentcontinuedtocovertheNorthAmericancraton.

Finally,inthelast2millionyearsorso,thenorthernpartofthecratonwas

shapedbyglaciers thatcamesouthduringcolderperiods.TheseglacierscameasfarsouthasMissouriintheGreatPlainsregion.WeareinawarmerperiodinEarth’shistorynow,andtheglaciershaveretreatednorth.Theyleftbehindlakesandrivers.

WORDSTOKNOWglacier:ahugemassoficeandsnow.

continentalplatform: thecentral,stablepartof thecratonthat iscoveredbysedimentsandsedimentaryrocks.

continentalshield: thepartof thecratonwhere theancientrocksareexposedandarenotcoveredbysediments.

WHAT’SHAPPENINGNOW?ThecentralpartoftheUnitedStatesislikethebackboneofthecountry.Youcanfindtheoldestrockshere,backtolongbeforeotherpartsofthecountryexisted.ThemostancientpartiscalledtheNorthAmericanCraton.

Thecratonhasbeenundisturbedbytectonicactivityforhundredsofmillionsofyears,anditshows.Youwon’tfindalotofactivevolcanoeshere.Eventheancient mountains have been eroded, leaving hundreds of miles of flat earth.Sometimes, though, there can be movement of the crust in areas of ancientrifting,causingearthquakes.

Mostoftheancientrocks,orcraton,arenowcoveredbyarelativelythinlayerofyounger,sedimentaryrocks.

Thispartofthecratoniscalledthecontinentalplatform,andincludesmostof theGreatPlains.Areaswhere the old rocks are exposedon the surface arecalledthecontinentalshield.MostofthecontinentalshieldisinCanada,buta

sectioncanbefoundinMichigan,Wisconsin,andMinnesota.

ANCIENTTIMETherocksinthecontinentalshieldaresomeoftheoldestrocksonEarth—over3billionyearsold.Howdogeologistsknowhowoldrocks are?They use differentways to figure out how long ago arock formed. Some methods work best for shorter time periods,likehundredsor thousandsofyears.Othermethodsarebetter formeasuringverylongtimeperiods,likemillionsorbillionsofyears.Radiometricdatingisusedtofindtheageoftheveryoldigneousandmetamorphicrocksinthecraton.

When magma cools to form igneous rocks, the rocks containvariouselements.Someoftheelementsareradioactiveanddecay,orbreakdown,overtime.Thismeansthattheatomsloseparticlesand become a new element. The starting element is called theparentandthestableelementitdecaysintoiscalledthedaughter.

Each kind of radioactive element decays at a known rate. Forexample, scientists know that after1.25billionyears, onehalf ofthepotassiuminarockwillhavedecayedtobecomeargon.Thisiscalledthehalf-life.Scientistscanmeasurehowmuchpotassiumisinarocksampleandcompareittotheamountofargon.Thishelpsthemtocalculatetheageoftherock.

WORDSTOKNOWradiometricdating:amethodofdeterminingtheageofrocks.Itlooks at a radioactive element in rock, such as uranium, andmeasureshowmuchithasdecayed.

element:asubstancethatismadeupofatomsthatareallthesame.

atom: the smallestparticleofmatter that cannotbebrokendownwithout changing theparticle’sproperties.EverythingonEarth ismadeofvariouscombinationsofatoms.

half-life: theamountof timeit takesforonehalfofaradioactiveparentelementtodecaytoitsdaughterelement.

DIDYOUKNOW?Voyageurs National Park in northern Minnesota is a hugeregion of ancient igneous andmetamorphic rocks. The rockshereareover2.5billionyearsold—that’solderthantherocksatthebottomoftheGrandCanyon.Theareahasbeenscouredbyglaciersandisnowcoveredbylakes.Infact,youcanonlygetaroundtheparkbyboat!

PLATETECTONICS:THEORIGINALRECYCLER

The earth has been recycling materials for over 4 billion years!Everyrockyouseehascomefromanotherkindofrock.Andeveryrockyouseewilleventuallybecomeanotherone.Allthisrecyclingis because of the movement of the plates pushing everythingaround.Tounderstandthisrecycling,firstyouhavetoknowabitabouttypesofrocks.

There are three main types of rocks: igneous, sedimentary, andmetamorphic.

IgneousRockshaveformedfromthecoolingofmoltenrock.As

yougodeeperbeneath thesurfaceof theearth, itbecomeshotter.At around 25 miles beneath the surface (40 kilometers), it’s hotenough to melt rocks. When that molten rock, called magma,comestothesurface,itcoolsintoigneousrocks.

Sedimentary Rocks form when small particles of rock, calledsediments,arepressed tightly together into rock.Sedimentscomefrom other rocks being eroded, or broken into smaller pieces bywind, water, ice, and gravity. Sedimentary rocks can also formfrom the remains of plants or animals being pressed together.Whenseawaterevaporates,themineralsandsaltsinthewaterstaybehindandcanformintorock.

Metamorphic Rocks formwhen heat or pressure changes rocksinto new rocks. Pressure, like temperature, increases as you gofartherbeneaththesurfaceof theearth.Ifrocksarepushedunderthe surface,butnot far enough tomelt, theycanbechanged intonewrockswithoutfirstmelting.

Igneous rocks can be eroded into sediments, which then formsedimentaryrocks.Thosesedimentaryrockscanthenbeburiedandheated and squeezed to form metamorphic rocks. Metamorphicrockscanbepusheddownintothemantleandmelted,tolaterformigneousrocks.Or itcouldhappeninreverse,becauseanytypeofrockcanformfromanyothertypeofrock.

MAKEYOUROWNWALKTHROUGHTIMEIt’shardtoimaginehowoldtherocksintheNorthAmericanCratonare.Howmuchis2billionyears?Trythisactivitytoputitallinperspective.

Grabafriendwho’sgoodatcounting.Pickaplacewhereyoucanwalkfor10minuteswithout stopping, likeawalkingpathor a schoolplayground.Startwalkingandcountoutloudtogetherforeverystepyoutake.Whenyougettothe steps listedbelow, say the step first, thenwhathappened in that “step.”Keepwalkingandcounting.Eachstepyoutakerepresents10millionyears!

Step1 Earthformed(4.6billionyearsago)Step57 OldestrocksonEarth(4.03billionyearsago)Step90 OldestrocksintheUnitedStates(3.7billionyearsago)Step210 NorthAmericancontinentbeginsforming(about2.5billionyearsago)Step260 NorthAmericancratongrowstothesouthfromArizonatoMissouri(1.8billion

yearsago)Step350 NorthAmericancratonbeginstoriftapart(1.1billionyearsago)Step390 InlandseasstarttofloodtheinteriorofNorthAmerica,depositingsediments(700

millionyearsago)Step406 Firstabundantlife(545millionyearsago)Step435 Firstdinosaurs(248millionyearsago)Step452 RockyMountainsform(80millionyearsago)Step455 Firstdogs(54millionyearsago)Step459½ Firsthumanancestors(5.5millionyearsago)Step460 Firsthumans(160,000yearsago)Step460 Presentday

1

2

MAKEYOUROWNPOPCORNTIME

SUPPLIES6ormoresmallbagsofunpoppedmicrowavepopcornmarkermicrowaveoven5piecesofpaperpencilgraphpaper

Usingthemarker, label5popcornbagswiththefollowing:0seconds,10seconds,20seconds,30seconds,and40seconds.Placeonebagofpopcorn

at a time in themicrowave and set the timer for 2minutes.As soon as thepopcorn begins popping, start counting the seconds. After the number ofsecondsmarkedonthebag,turnthemicrowaveoffandremovethebag.Forexample,removethebaglabeled0secondsassoonasitstartspopping.

Afterthebagshavecooleddown,openeachbagandspreadthecontentsona separate piece of paper. For each bag, count the number of unpopped

kernelsandthenumberofpoppedcornkernels.Recordtheresults,includingthenumberofkernelsandpoppedcorncombined.

3

4

Plottheresultsonthegraphpaper.Thehorizontalaxisshouldbethetime,from zero to 50 seconds. The vertical axis should be the percent of the

poppedkernels.Togetthepercentofpoppedkernelsforeachbag,dividethenumberofpoppedcornsbythetotalnumberofkernelsandpoppedcorn.

Drawahorizontallineatthe50percentmark.Alsodrawalineconnectingallofthepointsyouhaveplotted.Wheretheycrossisthehalf-lifeofyour

popcorn.

5Ifyou’d like,popanotherbagofpopcornforadifferent time,suchas15secondsor25seconds.Havea friendcount thekernelsandpoppedcorn,

and see if they can guess the amount of time itwas popped by using yourchart.Didtheycomeclose?

WHAT’SHAPPENING?Thekernelsareliketheparentelementinarock,andthepoppedcornislikethedaughterelement.Popcornhasashorthalf-lifecomparedtoelementsusedtodeterminetheagesofrocks,butthemethodissimilar.Scientistscountthenumberofparentelementscomparedtothedaughterelementstodeterminetheageoftherock.Justlikewithyourpopcorn,themoreparentelements

(kernels)thereare,theyoungertherock.Doyouseeacurvetothegraphthatyoumade?Radioactivitydecreasesovertimebecausethefewerparentsyouhave,thesloweryoulosethem.Thesameistrueforthepopcornonceitgets

going.

I

CHAPTER2

MOUNTAINRANGESfyoutravelwestacrosstherelativelyflatGreatPlains,youcomesuddenlyupon one of the great mountain chains of the world. The Rocky

Mountainsriseabruptlywithspectacular,snowcappedpeaks.Howdidtheyform?What’sthere?Let’sfindout!

ROCKYMOUNTAINSTheRockyMountains,oftenjustcalledtheRockies,areamajormountainchainin North America. The mountains stretch almost 2,000 miles from BritishColumbia in Canada south to NewMexico (3,200 kilometers).Many smallermountain rangesmakeup theRockies, suchas theGrandTetons inWyomingandtheFrontRangeinColorado.

WORDSTOKHOWAncestralRockies:amountainchainthatformedover300millionyearsago.Thesemountainswereeroded,buttherocksformedthencanbeseenintoday’sRockyMountains.

TherocksthatyoufindintheRockyMountainsformedlongago,overmanymillions of years. Some rocks formed from volcanoes, and others duringcollisionsofancienttectonicplates.TheseAncestralRockieserodedovertime.Inlandseas thenfloodedmostof the interiorofNorthAmerica,whichcoveredtheseoldrockswithsediments.

Then, in the time of the dinosaurs, theNorthAmerican continent collidedwithanoceanicplatetothewest.Whenthesubductionbegan,theoceanicplatepushedunderNorthAmericaatasteepangle,whichishowsubductionnormallyhappens.ThisformedthePacificMountainSysteminWashington,Oregon,andCalifornia.

Around70to80millionyearsago,geologiststhinkthesubductionchanged.Theoceanicplatestartedtosubductatamuchflatterangle.Itcausedtherocksfarinlandtoarchintolargefolds,andpilesofrockswerethrustontopofeachother.ThispushingupofrocksformedtheRockyMountains.Therehavebeenother periods of uplift as well as volcanic activity that have formed smallerrangesinthechain.TheRockiesarecomplicatedmountains!

When the Rockies were first uplifted, they were probably much like theHimalayas are today—more than 20,000 feet above sea level (6,096 meters).Scientistsestimate thatalmost2milesof sedimentary rockshaveerodedawayfrom the top since then (3 kilometers).The older rocks,which are harder, areexposedinmostareas.

About 2 million years ago, the earth became cooler and wetter. Glaciersbegan scraping themountains. Theway theRockies look today is due to thiserosion and the effect of glaciers. Different kinds of rocks erode differently,giving the landscape different shapes. For example, granite is a hard, igneousrock that erodes to rounded forms. Crystalline metamorphic rocks erode tojaggedpeaks.

CONTINENTALDIVIDEThe Continental Divide is an imaginary line that runs north tosouth in North America. Water on the east side of the divideeventually flows to the Atlantic Ocean, while water on the westside flows to the Pacific Ocean. The divide follows a line thatconnectsthehighpeaksintheRockies.

From Triple Divide Peak in Glacier National Park in Montana,waterflowstothreedifferentoceans,includingHudsonBaytothenorth. The International Hydrographic Organization lists HudsonBay as part of theArcticOcean.This is the only place onEarth

wherewaterflowstothreedifferentoceansfromasinglepoint.

DIDYOUKNOW?WhentheRockiesformed,theupliftofthemountainsfracturedthe crust and allowed molten minerals to rise. The cooled

mineralsformedrichveinsofcopper,gold,andsilver.Notlongafter the famousGoldRushofCalifornia in1849, therewere“rushes” for gold and otherminerals throughout theRockies,includinginMontana,Wyoming,andColorado.

WILDLIFETheRockyMountainssupportavarietyofplantsandanimals.Theyhavehadtoadapttotheharshconditionsinmanyways.

Mountain goats have hoofs that are rubbery on the underside and sharparoundtheedges.Thishelpsthemgripslipperyledgesatthetopsofmountains.Ifyouhikeinthemountains,therubberysolesofyourhikingbootswillstopyoufrom slipping too. Why do mountain goats climb so high? Large predatorsaren’tsonimbleandwon’tfollowthem.

Ptarmiganslookabitlikeachicken.Whilemostbirdsmigratetowarmerclimatesinthewinter,ptarmigansstayallwinterlong.Whenfoodisscarce,theyeattwigs.Ptarmiganshavewhitefeathersinthewinter,andmottledbrowninthesummer.Thishelpsthemblendintotheirsurroundingsandhidefrompredators.Theyalsogrowthickfeathersontheirfeetinthewintertohelpthemwalkontopofthesnow—justlikesnowshoes!

WORDSTOKNOWadapt:changesaplantoranimalmakestosurvive.

predator:ananimalthathuntsanotheranimalforfood.

migrate:tomovefromoneplacetoanothereachyear.

Ptarmigan

GrizzlyBear

GrizzlybearsarefoundinthenorthernRockies.Theycangrowto8feettall(2½ meters), and weigh as much as three refrigerators (800 pounds/363kilograms).Theyloveberriesandmountaintrout,atypeoffishfoundinmanymountainstreams.

GoldenEagle

Golden eagles are the largest birds of prey in the Rocky Mountains.Femalescanreach6½feetfromwingtiptowingtip(2meters),andcanweigh12pounds(5½kilograms).

Bighorn sheep have special hooves to help them jump and climb aroundcliffs. Thick coats of hair, two layers thick, help them keep warm in frigidconditions.Bighornsheepareknownfortheirlargehornsthatcanweighupto30pounds(14kilograms).Largemalesheepfightbychargingateachotherandcrashingtheirhornstoprovewho’sthebiggestandtoughest.

BighornSheepThenumberofbighornsheepdeclined100yearsagobecauseof

hunting,changesintheirhabitat,anddisease.Butaspeoplebecameconcerned,thesheepwereprotectedinnationalparksandbyrestrictionsonhunting.OneofthefirstcampaignstosavebighornsheepwasbytheBoyScoutsinArizona.NowtherearehealthypopulationsofbighornsheepthroughouttheRockies.

WORDSTOKNOWbirdofprey:abirdthathuntsanimalsforfood.

habitat:thenaturalareawhereaplantoranimallives.

HIGHMOUNTAINSPike’sPeakisoneofthemorefamousmountainsintheRockies.Itis 14,115 feet high (4,302 meters). That’s taller than 11 EmpireStateBuildingsstackedontopofeachother!Itsitsrightalongtheedgeof theGreatPlains, and is visible from far away.KatherineLee Bates wrote the song “America the Beautiful” in 1893 afterseeing the view of the Rockies and the plains from Pike’s Peak.Her words, “For purple mountain majesties, Above the fruitedplain,” refers to the Rockies, which can look purplish from adistance, rising high above the Great Plains. Colorado has 53mountainsthatareabove14,000feethigh(4,267meters).

Thehighest“mountain”ineachstateoftheregionislistedbelow.You might notice that some states list a “point” or “hill” or“mound”becausetheydon’treallyhaveanymountains.

Colorado Mt.Elbert 14,433feet(4,399meters)Wyoming GannettPeak 13,804feet(4,207meters)Montana GranitePeak 12,799feet(3,901meters)SouthDakota HarneyPeak 7,242feet(2,207meters)Nebraska PanoramaPoint 5,424feet(1,653meters)Kansas Mt.Sunflower 4,039feet(1,231meters)

NorthDakota WhiteButte 3,506feet(1,069meters)Minnesota EagleMountain 2,301feet(701meters)Michigan Mt.Arvon 1,979feet(603meters)Wisconsin TimmsHill 1,951feet(595meters)Missouri TaumSaukMountain 1,772feet(540meters)Iowa HawkeyePoint 1,670feet(509meters)Ohio CampbellHill 1,549feet(472meters)Indiana HoosierHillPoint 1,257feet(383meters)Illinois CharlesMound 1,235feet(376meters)

WORDSTOKNOWalpineglacier:aglacierthatformsinthemountains.

cirque:abasinattheheadofaglacialvalley,whichoftencontainsalake.

U-shapedvalley:avalleythathasbeencarvedbyaglacierandhasashapeliketheletter“U,”withsteepsidesandaflatfloor.

ALPINEGLACIERSGlaciers are large areas of ice that move. They form when snow falls in thewinteranddoesn’tmelt in thesummer.Thesnowgetsdeeperandheavierandcompresses thesnowcrystals,which lock together.Alpineglaciersoftenforminthehighestmountainsbecause it issocold there,but theyaremuchsmallerthanthelargesheetsoficethatcovercontinents.TheWindRiverRangehas63glaciers, the most in the American Rocky Mountains. Glaciers can be foundthroughouttheRockies.

Alpine glaciers in the Rockies are mostly cirque glaciers. Snow canaccumulate in these bowl-shaped areas at the head of valleys high in themountains,formingsmall,roundglaciers.Ifacirqueglacierlatermelts,itoftenformsalakeorpond.

Duringthepast2millionyears,therehavebeenmanyperiodswhentheearthwasmuchcolder.Thisallowedglacierstocomefartherdownthemountainsintothevalleys.Forexample,theglaciersinGlacierNationalParkhaveformedandmeltedmanytimes.Theonestheretodayformedinthelastfewthousandyearsastheclimatebecamecolder.Theyareshrinkingtodayastheclimatebecomeswarmer.

Aslargerglaciersmove,theypickuprocksandevenboulders,whichcarvethelandscape.Herearesomethingstolookforthattellyouaglacierhasbeenaround:Cirques:These largebowls that format the top,orhead,ofaglacieroftenfillwithwater,formingasmalllake.Itlooksalmostlikeagianttookabigscoop of ice cream out of the mountain. There are cirques throughout theRockies.

U-Shaped Valleys: River valleys are V-shaped, from the river slowlycuttingintotherock.Glaciersfollowthepathofriversbecause,likerivers,theyareseekingthefastestwaydownhill.Butglaciersarewider,andtherockstheycarrycarveoutavalleywitha“U”shape.

Eventhoughtheyareslow,glaciersareextremelypowerful.Theymoveasidejustaboutanythingintheirway—trees,rocks,andevenlarge

boulders.

Glaciersbecomeabitlikesandpaperastheypluckuprocksandcarrythemdownhill. This sandpaper erodes the land into U-shaped valleys and sharpmountain peaks. In Rocky Mountain National Park, there are numerous U-shaped valleys including Forest Canyon and Fall River Valley. McDonaldValleyinGlacierNationalParkisanothergreatexampleofaU-shapedvalley.

DIDYOUKNOW?The mountains in the Never Summer Range in the RockyMountainsofColoradoaresnowcappedthroughouttheyear.

Hanging Valleys: When a smaller glacier in a side canyon feeds into a

larger glacier, the smaller glacier doesn’t cut as deeply as the larger glacier.Aftertheymelt,thesmallerglaciersleavebehindsmallervalleyshighuponthemountainsidesthatlooklikethey’rehanging.Youcandrivearoundtherimofavalley called “HangingValley” in RockyMountain National Park. In GlacierNationalPark,awaterfallcalledBirdwomanFallsspillsfromahangingvalleyonMt.Oberlin.

WORDSTOKNOWhangingvalley:asidevalleythatjoinsthemainvalleyatahigherlevel. It formswhen a smaller glacier doesn’t erode as deeply asthemainglacier.

moraine:anaccumulationofgravelandsanddepositedatthefrontofaglacier.

PolishedRocks:Astheglacierdragssmallerrocksoverbedrockbelow,thesmallerrocksgrindasmoothorgroovedsurface.

Moraines: Remember how glaciers pick up lots of rocks?What happenswhen theglaciermelts at thebottom?The rocksaredumpedout.Because theglacier acts like a conveyor belt made out of ice, more and more rocks aredumpedout,formingpilesofrocksatthebottomandsidesoftheglacier.Recentmoraineslookjustlikeapileofrocks.Oldermorainesarecoveredbysoilandplants.

Horns:These are steep-sidedmountainpeaks.They are formedby twoormore glaciers carving from different directions. Kinnerly Peak in GlacierNational Park and numerous mountains in Grand Tetons National Park areexamplesofhornscreatedbyglaciers.

DIDYOUKNOW?

TherearefournationalparksintheAmericanRockyMountains:GlacierNationalParkinMontana,YellowstoneandGrandTetonNationalParksinWyoming,andRockyMountainNationalParkinColorado.Therearefivenationalparksinthe

CanadianRockies.

SNOWANDAVALANCHESThe record for the most snowfall in the Rockies was set in thewinter of 1978-1979, when 70 feet of snow fell onWolf CreekPass in Colorado (21 meters). That’s as high as a six-storybuilding! Deep snow causes avalanches, and avalanches arecommon in theRockies.Theyarehugemassesof snow, ice, androcksthatslidedownmountainsides.Avalanchescantravelat130milesperhour(209kilometersperhour).That’stwiceasfastasacardrivesonthehighway!

WORDSTOKNOWplateau:alarge,raisedareathatisfairlyflat.

limestone: a sedimentary rock that forms from the skeletons andshellsofseacreatures.Limestoneerodeseasily.

cave: a natural underground opening connected to the surface,largeenoughforapersontoenter.

THEOZARKSTheOzarkMountains stretchacross southernMissouri andnorthernArkansas,aswellastheeasterncornersofKansasandOklahoma.Thesemountainsbeganasabroad,upliftedarea that formedaplateau.Later, theareawascrossedby

rivers,which cut valleys into the plateau.Themountains themselves arewhatusedtobethetopoftheplateau.WhiletheOzarksarenowherenearashighasthe Rockies, they’re the largest mountains between the Rockies and theAppalachians in the east. The highest Ozark peak is Turner Ward Knob inArkansas,whichis2,463feettall(751meters).

The region has large areas of limestone, where caves and springs haveformed.Missourihasover6,000cavesandisknownasthe“cavestate.”

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MAKEYOUROWNFOLDEDMOUNTAINS

SUPPLIESatleast3colorsofplayclayrollingpintableknife

Rollouteachcolorofclayintothesizeandshapeofaverylargepancake,about¼inchthick(½centimeter).Ifyouhaveenoughclay,rolloutextra

layers.Stackthelayersontopofeachother,alternatingcolors.

Placeyourhandsontheoutsideedgesofthestackandgentlypushtowardsthemiddle.Theclayshouldforminto2or3folds.Youmayhavetoliftthe

middleup tohelp it form the folds. It’sokay if the folds flopoverabitontheirsides.This is like two tectonicplatescollidingandforcing thecrust tofold.

Rotatethefoldedclay90degrees.Repeatstep2sothatyouarefoldingthefolds.Youwill need to lift themiddle to form the second fold.The clay

shouldhaveroughdomeshapes.

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Withthetableknife,sliceoffthetop½inchofthedomes(1centimeter).Howdothelayersofclaylook?Tryslicingverticallyalongonesideofthe

dome.Thentryslicingatanangle.Thisisliketheerosionofrocks.

Trythisagainwithnewclaybutexperimentwithdifferentwaysoffoldingtheclay.

WHAT’SHAPPENING?Whentectonicplatesareonthemove,rocksareoftenburiedatgreatdepthswhereit’smuchhotter.Whenforcesactonthesehotrocks,theycanfold,justlikeyourclay.Often,rocksgetpushedfromdifferentdirectionsovertime.Whenthathappens,foldsintherockscangetre-folded,whichiscalledsuperposedfolding.Thisiswhathappenedwhenyoure-foldedyourclay.

Then,whentherocksarelaterupliftedabovethegroundanderoded,thefoldsandrocklayerscanlookdifferentdependingonwheretheerosionhappened.

Thesamethinghappenedwhenyoucuttheclayatdifferentangles.

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CHAPTER3

VOLCANOESANDEARTHQUAKES!he stable interior of the United States doesn’t seem like the place forhazards like volcanoes and earthquakes. Have you ever heard of a

volcanoinKansas?Butifyouscratchbeneaththesurfaceofthethicksoils,you’llfindvolcanoesandearthquakeswithaviolentpast—andthey’restillactivetoday!

VOLCANOES!Volcanoesformwhenmagmacomestothesurface.Sometimesthisliquidrockcoolsbefore it reaches the surface.When thathappens, it forms rocks suchasgranite.Butwhen themagmacomesall theway to thesurfacebefore itcools,it’scalledlava.Theniteruptsthroughanopeningintheearthcalledavolcano.

TheRockyMountains contain rocks thatwere formed fromvolcanoes thateruptedmanymillionsofyearsago.EventheGreatPlainshavevolcanicrocksdeep beneath the surface. These rocks formed even farther back in the past,whenthecontinentwasstillbeingputtogether.

Butifyou’reinterestedinseeingactivevolcanicfeatures,there’sonlyoneplacetogointheRockiesorGreatPlains:Yellowstone!

WORDSTOKNOWerupt:toburstoutsuddenly.

hotspring:anaturalpoolofwaterthatisheatedbyhotormoltenrock.Hotspringsarefoundinareasofvolcanicactivity.

geyser:ahotspringthatperiodicallyejectswaterandsteamintheair.

thermal:relatedtoheat.

DIDYOUKNOW?The tallest active geyser in the world is at YellowstoneNationalPark.SteamboatGeysershootswaterandsteamupto300feethigh(91meters)!It’snoteasytosee,though.ThelasttimeSteamboatGeysereruptedwasin2005.

YELLOWSTONEBubbling mud pots, gorgeous aqua-blue hot springs, and explosive geysers.That’swhat you’ll see if you visitYellowstoneNational Park.Yellowstone isournation’soldestNationalPark,establishedin1872.

It has incredible wildlife and scenery, but is best known for its volcanicfeatures.Thereare10,000thermalfeatureslikegeysersandhotsprings.Thisisoverhalfofallthethermalfeaturesintheworld!

Ageyser is a huge fountainof hotwater and steam that explodes upward.

Aroundtheworld,geysersarerare,butYellowstoneisfullofthem.Ithas300geysers,whichisoverhalfofall thegeysers in theworld.Yellowstone’smostfamousgeyser is calledOldFaithful. It’s themost regulargeyser in theworldthatisover100feethigh(30meters).Iteruptsaboutevery90minutes,shootingupto8,400gallonsofboilinghotwater(32,000liters)foraslongas5minutesandashighas184feet(56meters)!

WORDSTOKNOWmudpot:aboilingareaofmud.

fumarole:aventthatletsouthotgases.

Howdothesevolcanicfeaturesform?Youneedthreethings.

Heatfromhotmagmathathasbeenbroughtclosetotheearth’ssurface.

Water from rain and snow that has seeped into the earth deep enough tocomeclosetothemagmaandabsorbitsheat.Heatandwatertogetherproducesallsortsofinterestingvolcanicfeatures,suchasmudpots,fumaroles,andhotsprings.

Blockage to create the most unusual thermal feature—a geyser. You alsoneedaspecialkindofplumbingsystem.Geysershaveverticaltubesthatconnectundergroundareas that store lots ofwater to the surface.As thewater storageareasfill,thetubeslowlyfillsupwithheatedwaterandgasbubbles.

Inageyser,thegasbubblesaretrappedbyablockage.Whenthegasbubblesfinally break free, they explode upward with the hot water. This triggerssuperheatedwaterfrombelowto turntosteamandexplodeupward,formingagiant, gushing geyser! The system then slowly refills with water, starting thecycleoveragain.

Yellowstone also has the largest active volcano in the United States, andprobablyintheworld.Youmayhaveheardoftheeruptionin1980ofMountSt.HelensinWashingtonState.Itkilled57peopleanddestroyedbridges,railways,trees,and200homes.

ComparedwitheruptionsfromtheYellowstonevolcanoinWyoming,MountSt.Helenswasababy.Thisisavolcanothatcouldproducethousandsoftimes

asmuchashandlavaasmostvolcanoes.

TheYellowstonevolcanoissolargeandpotentiallydestructive,it’scalledasupervolcano.

DIDYOUKNOW?An active volcano is a volcano that has erupted in recordedhistory. Geologists think it will erupt again, probably in thenext200years.Adormantvolcano isa“sleepy”volcano thathasn’t erupted in recorded history, but could erupt again. Anextinctvolcanoisonethathasn’teruptedinmanythousandsofyearsandisn’texpectedtoeruptagain.

Yellowstone first erupted about 17million years ago, and has had at least140 large eruptions. The Yellowstone volcano had three giant eruptions 2million, 1.3million, and 642,000 years ago. One produced about 2,500 timesmore ash than the 1980 eruption ofMount St. Helens. Yellowstone is such alargevolcanobecauseitisfedbyahugesourceofheat.ScientistsestimatethattheundergroundplumeofhotandpartlymoltenrockthatfeedstheYellowstonevolcanoisabout400mileslong(644kilometers)!

WORDSTOKNOWcaldera:alargevolcaniccrater,usuallyformedbyalargeeruptionthatcollapsesthemouthofthevolcano.

DIDYOUKNOW?The largest eruption of theYellowstone volcano produced anashcloud10mileshigh(16kilometers).Itspewedenoughashto cover half of North America in ash up to 6 feet thick (2

meters).

Instead of the typical cone shape of many volcanoes, the Yellowstonevolcanositsonavastdepression,orsunkenarea.Whenavolcanowithaverylarge magma chamber erupts, the volcano collapses after all that magma hasbeen expelled. This forms a caldera where the magma chamber once was.Yellowstone’scalderais34milesby45miles(55by72kilometers).Itisfilledwithlakesandhotsprings.

Yellowstone is still considered active because of all of its hot springs andgeysers, even though it isn’t currently erupting with ash and lava. GeologistshavebeenmonitoringgeologicactivityatYellowstoneNationalParkforover30years. They think it will be thousands of years before anothermajor eruptionoccurs.

WHYINWYOMING?

Most volcanoes form around the edges of tectonic plates.This iswhereoneplate issubductingbeneathanother,orwhereriftingisoccurring.Nearly all of the active volcanoes in theUnites Statesare along its west coast where the Pacific Plate is subductingbeneath the North American Plate. Why is Yellowstone, in themiddleofthecontinent,thesiteofthelargestvolcanointheUnitedStates?

Scientists think theYellowstone volcano is caused by a hot spotfrom deep in the earth that ismelting rock closer to the surface.Hotspots are small, extremely hot regions beneath the surface ofthe earth that usually occur in themiddle of a plate.Asmaterialrisesoverahotspot,itmelts.

Asavolcanomovespastthehotspot,thatvolcanoslowlydiesoutandanewoneformsoverthehotspot.TheNorthAmericanPlateismoving southwest about 1 inch per year over the Yellowstonehotspot (2½ centimeters). The Yellowstone hotspot first formedbeneathwhere Idaho, Nevada, andOregon come together. It hasmigrated slowly to its present location at Yellowstone NationalParkinnorthwestWyoming.

EARTHQUAKES!Have you ever felt an earthquake?When stress builds up in rocks, they cansuddenlylurchintoanewposition.Thatlurchingiscalledanearthquake.Mostearthquakeshappenalongfaults,whicharecracksintheouterlayeroftheearth.

Whenanearthquakeoccurs, it releaseshugeamountsof energy.Wavesofenergytraveloutinalldirectionsasseismicwaves.It’sabitliketossingalargerockintoapond.Theripplesofwaterspreadoutinalldirections.

WORDSTOKNOWseismic wave: a wave of energy generated from an earthquake.Thewavetravelsthroughtheearth.

Faults don’t open up and there’s no giant hole you can fall into when anearthquakeoccurs.Anearthquakeismovementthathappensalongthefault.Infact,thewholereasonanearthquakeoccursisbecausefaultsget“lockedup”duetofriction.Inanearthquake,thetwosidesofthefaultlurchintoanewposition.If the fault opened up, there would be no friction. Sometimes there can be ashallowopeningintheearthafteranearthquakebecauseofalandslide.

NEWMADRIDSEISMICZONEDoyouknowwhichstate intheUnitedStateshadtheearthquakethataffectedthe largest area in recorded history?Doyou think ofCalifornia? It’s true thatCalifornia has lots of earthquakes.But the earthquake that affected the largestareahappenedinthecenteroftheUnitedStates,inNewMadrid,Missouri.

TheNewMadridseismiczoneisasystemoffaultsrightinthemiddleoftheNorth American Plate. The area is whereMissouri, Kentucky, Arkansas, andTennessee meet. There are several faults here about 150 miles long (241kilometers),fromArkansastosouthernIllinois.

In 1811 and 1812, there were three huge earthquakes along these faults thatmeasured7.5to8.0ontheRichterscale.Sincetheyhappenedbeforethereweremodern instruments to measure earthquakes, scientists have to estimate theirstrengthbasedonnewspaperreportsandlookingatchangesintherocks.

These were the largest quakes east of the Rocky Mountains in recordedhistory. They were felt farther than much larger ones in Alaska because theolder,colderrocksinthecratontransmitseismicwavesfarther.PeoplefeltthemfromtheRockyMountainstotheAtlanticOceanandfromCanadatoMexico.

WORDSTOKNOWRichter scale: a scale used to measure the strength of anearthquake.

seismograph: an instrument that measures the intensity of aseismicwave.

SidewalksbuckledinBaltimore,Maryland.ChimneysfelldowninCincinnati,Ohio.ChurchbellsranginBoston,Massachusetts.

InWashington,D.C.,President JamesMadisonandhiswifeDolly thoughtsomeonewasrobbingtheWhiteHouse.AndthebanksontheMississippiRivercollapsed.Insomeplaces theearth tiltedsomuchthat theriverranbackwardsforawhile!

Willanother“BigOne”happen?Theonlyquestioniswhen.Eachyearthereare about 500,000 earthquakes that are detectable by seismographs. About100,000ofthemcanbefeltbyhumans.About100ofthemcausedamage.IntheareaofNewMadrid,thereareearthquakesonmostdays,butusuallyyoucan’tfeelthem.

HOWBIGISTHATEARTHQUAKE?

Earthquakesaremeasuredmainlybytheirmagnitude.MagnitudeisthestrengthofanearthquakeandisrecordedontheRichterscale.Whenthemeasurementincreasesby1,themagnitudeincreasesby10.Soanearthquakethatmeasures8.0is10timesaspowerfulasanearthquakethatmeasures7.0.Herearesometypicaleffectsthatpeople might feel near the epicenter of earthquakes of variousmagnitudes.Thisisthepointontheearth’ssurfacedirectlyabovethelocationoftheearthquake.

MagnitudeontheRichterScale

WhatitFeelsLike HowOftenTheyOccurintheWorld

Below3.0 Youusuallycan’tfeelit. 1,000perday3.0to3.9 Youcanfeelaslighttrembling,but

thereisnodamage.Over100perday

4.0to4.9 Tablesandchairsrattle. About20perday5.0to6.9 Somedamagetobuildings,especiallyif

they’repoorlybuilt.About3perday

7.0to7.9 Seriousdamagetobuildings,withsomedestroyed.

18peryear

8.0to8.9 Seriousdamageforseveralhundredmiles.

1peryear

9.0to9.9 Devastating,affectingpeopleforthousandsofmiles.

1per20years

10.0andup Neverrecorded. ?

TheNewMadrid areahas experiencedmajor earthquakesover thepast 65million years, but only once everymillion years or so. That rate seems to bespeedingup lately.The last2,000yearshavehadbetween twoandfourmajorearthquakes.

Scientiststhinktheremaybemorefrequentearthquakesbecauseofchangingpressuresonthecrustfrommeltingglaciersinthelast18,000years.Theythinka major earthquake is 100 or more years off, but a smaller, still dangerousearthquakeofperhapsmagnitude6.0willprobablyhappensooner.Thiswoulddamagebridgesandbuildings.

BIGEARTHQUAKESINTHEPASTA significant earthquake usually leaves a record in the rocks. Geologists canreadthatrecord,justlikeyouwouldreadabook.Theylookcloselyatfaultsthathavemovedinthepast10,000years.Thesearethebestpredictorsofwhenandwhereearthquakesmightoccurinthefuture.Whatdogeologistslookfor?

Paleoliquefaction is evidenceof liquefaction thathasoccurred in thepast.Liquefactioniswhensoilflowslikealiquid,usuallyduetoalargeearthquake.The vibrations from the earthquake loosen the water-filled soil and break thegrain-to-grain contact. Sometimes sand “boils”when the liquefied sand burststhroughsurfaceclayandspillsontotheearth’ssurface.

TheNewMadridearthquakesproduced lotsof sandboils.This isbecause,overmillionsofyears,theMississippiRiverhasdepositedhugeamountsofsandcoveredoverbyclay.Scientistscanseethesecircularareasofsandboilsusingpicturestakenfromtheair.

DIDYOUKNOW?

The largest recordedearthquake in theworldwas inChileonMay 22, 1960. It measured 9.5 on the Richter scale.Seismographsallovertheworldrecordedtheseismicwavesforseveraldays.Theentireearthwasshaking!

WHYINMISSOURIANDARKANSAS?

Like volcanoes,most earthquakes occur near the edges of plates.For example, the famous SanAndreas fault system in Californiaoccurs where two plates grind past each other. The massiveearthquake in Japan in March 2011 that caused the devastatingtsunamiwasalsotheresultofplatesmovingpasteachother.Otherearthquakescanoccurasoneplatesubductsbeneathanother.

The New Madrid seismic zone is in the middle of the NorthAmericanPlate, but it’s still affected by themovement of plates.Scientists think that about 500 million years ago, the continentstarting rifting apart there. Even though the rifting stopped, thecrust is still weak in this area. The faults that formed from therifting were later covered by sediments. But they’re like a scarburied under the sediments that hasn’t completely healed.Whenpressurebuilds frommovements in the earth, these old faults areplacesthatareweaker,soearthquakesoccurthere.

Stalagmites areanotherclue.Thesearecave formations that scientistscanstudy to date an earthquake. Stalagmites grow slowly into cone-shapedformationswhendripsofwaterfilledwithmineralsfallonthegroundofacaveandslowlybuildup.

Iftheearthmovesinanearthquake,thesourceofthedripmovestoo.That

makes the growth of the stalagmite shift, and you can see where it changes.Scientists cut paper-thin slices where the change happened and analyze themineralstotellwhenthecrystalsformed.Thisisthedateoftheearthquake.

DIDYOUKNOW?AUnitedStatesGeologicalSurveywebsiteshowsearthquakesover the last seven days for the United States. Go tohttp://earthquake.usgs.gov/earthquakes/.Thereareusuallydotsforearthquakesaroundthe“bootheel” inthesoutheastcornerofMissourifortheNewMadridseismiczone.

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MAKEYOUROWNLIQUEFACTION

SUPPLIESlargebowlicecubes,enoughtofillthebowlhalfwayshortstickcoldwatercuporpitcher

Fill the bowl about halfway with ice cubes. Place the stick into the icecubessothatitisverticalandstandingonitsown.

Using the pitcher, slowly pourwater into the bowl. Stopwhen thewaterlevelisbelowthetopoftheicecubes.Isthestickstillvertical?

Continue filling thebowlwithwateruntil the icecubes float. Is the stickstillvertical?

WHAT’SHAPPENING?Whenloose,sandysoilissaturatedwithwater,thewaterfillsthegaps

betweenthegrainsofsand.Undernormalconditionsthegrainsstilltouch

eachothersothesandisfirmandcansupportbuildings.Thisislikewhenthewaterwasbelowthetopoftheicecubes.Whenanearthquakeoccurs,the

shakingputspressureonthewaterandthesandbecomesbrieflysuspendedinthewater.Thegrainsarenolongertouchingeachotherandtheycan’tsupportobjects.Thisiscalledliquefaction,becausethesandysoilbehaveslikealiquid.Buildingscantiltorsinkintothesquishysoil.Inyourexperiment,whentherewasenoughwaterfortheicecubestofloat,thecubesnolonger

touchedeachother,andtheycouldn’tholdupthestick.

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MAKEYOUROWNGEYSER

SUPPLIES2indexcardscellophanetape2-literbottleofsodarollofMentoscandy

Rolloneoftheindexcardsintoatubeaswideastheopeningofthebottle.Placetapearoundthetubeat thetopandbottom,leavingbothendsopen.

Open the bottle of soda and set it on the ground outside so it is stable anddoesn’ttipover.

StacktheMentosintheindex-cardtube.Placethesecondindexcardontopofthetubeandturnthetubeupsidedown.Placebothontopoftheopening

ofthebottlesothatthetubeisjustovertheopening,withtheflatindexcardinbetween.

PullouttheindexcardandlettheMentosslideintothesoda.Standback!

WHAT’SHAPPENING?Sodaisbubblybecauseitcontainsgasesdissolvedinwater.Thisgaswas

dissolvedintothesodaatthefactoryunderhighpressure.Whenyouopenabottleofsoda,itreducesthepressureandallowsbubblestoform.AddingtheMentoshelpsthebubblesformmuchfaster.Theyformsofasttheyexplodeupwardoutofthebottle,takinglotsofsodawiththem.Whenhotwaterandgascomeneartheearth’ssurface,theyformhotsprings.Butsometimesthepathwayisblockedandthepressurebuildsuplikewhenthecapisonasodabottle.Whenthewaterandgasfinallybreakthroughtheblockage,they

explodeinafountainofhotwaterandsteam.

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CHAPTER4

THEPLAINSromtheRockyMountainsinthewesttotheAppalachianMountainsintheeast,thePlainsspreadfartherthanyoucansee.Thesevastexpanses

offlatlandaretheheartofAmerica,coveredingrassandfieldsofcornandwheat.

OLDROCKSANDANEWSHAPEThe central part of theUnited States contains its oldest rocks, dating back tolong before the rest of the country existed. The Plains are part of the NorthAmericanCraton,whererocksarehundredsofmillionsofyearsold.SomerocksinnorthernMinnesotaarebetween3.5and3.7billionyearsold!

WORDSTOKNOWacidic:fromacids,whicharechemicalcompoundsthattastesour.

carbondioxide:agasformedbytherottingofplantsandanimalsandwhenanimalsbreatheout.

carbonicacid:aweakacidformedwhencarbondioxidedissolvesinwater.

Mostofthecratonwascoveredbyathin,flatlayerofyoungersedimentaryrockswhen a shallow sea swept into the interior part of the country. The seaadvancedandrecededmanytimes.Becausetherehasn’tbeenmountain-formingtectonicactivityinthisregionsincethen,theregionhasremainedrelativelyflat.Inmuchmorerecenttimes,glaciersmovedintotheNorthernPlainsandcarvedthesurfaceoftheland.

LOOKOUTBELOW:CAVES!The Plains have thousands of caves of all shapes and sizes. Some are just ashallowhollowintheearth,whileotherswindfortensorevenhundredsofmilesintotaldarkness.Mostofthemarelimestonecaves.

ThicklayersoflimestoneweredepositedwhenashallowseacoveredtheinteriorofNorthAmerica.

Limestone is a type of rock that dissolves in slightlyacidicwater.Lemonjuiceandvinegarareacids,soifyouaddedafewdropsoflemonjuicetowateritwouldbeslightlyacidic.Tasteplainlemonjuiceandtheacidinitwillmakeyour mouth pucker! All rainfall is naturally slightly acidic because carbondioxideintheairreactswithwatertoformcarbonicacid.

WORDSTOKNOWcavern:averylargecaveorsystemofconnectedcaves.

Limestoneoftenhascracksinit,andrainwaterseepsintothesecracks.Thecarbonic acid in the rainwater slowly dissolves the rock, making the crackswider.Insomecaves,astreamcantravelthroughthelimestoneuntilitfindsanoutlet,erodingevenmore rockalong theway.Eventually,partof the roofcancollapse,whichformslargercaverns.TherearemanycavernsinthePlainsthatbeganformingnotlongaftertheinlandsearecededandlimestonewasexposed.

JEWELCAVEJewelCaveinSouthDakota isoneof themostbeautifulcaves intheworld.It’salsothesecondlongest.Sofar,cavershaveexplored155miles (249 kilometers) of the cave, but they aren’t finished.Basedonstudiesdonewithmovementsofair,scientiststhinkitisthousandsofmileslong!

Mixedinwiththelimestoneisanothermineral,calledgypsum.Theseepingrainwaterpicksupbitsofgypsum,which it thendepositsin thecaves.Gypsumformationsareverydelicate,andtheyformonlyindrypartsofthecave.Thisisbecausegypsumdissolvessoeasily inwater. Jewel Cave has gypsum crystals that are formedlikeflowers,needles,beards,andspiders.YoucanvisitJewelCaveandseetheseamazingformationsforyourself!

WORDSTOKNOWspeleothem:adistinctivecaveformation,suchasastalactite.

stalactite:acaveformationthatlookslikeaniciclehangingfromtheceiling.

stalagmite: a cave formation that sticks up from the floor, oftenunderastalactite.

CAVEFORMATIONSOncecavernsform,caveformationsofallshapesandsizescandevelopthatlooklike teeth, columns, curtains, pearls, and beards! These cave formations arecalledspeleothems.As rainwaterseeps through limestoneanddissolves it, thelimestonedoesn’tdisappear—it’s just in thewater.Whenwaterdrips fromtheceilingofacave,averysmallbitoflimestoneisleftbehind.Dropbydrop,hugespeleothemsform.Maybeyou’veseenpicturesofstalactitesandstalagmites.

Thekindofspeleothemformeddependsmainlyonwhetherthewaterdrips,trickles,orseepsintothecave.

Stalactitesgrowwherewaterdripsfromtheceiling.Stalagmitesgrowwherewaterdripsontothefloor.Draperiesgrowwherewaterrunsdownaslantedceilingorwall.Columnsarewhereastalactiteandstalagmitemeet.Soda straws are hollow tubes that grow where water seeps through theceiling.Theycanturnintoastalactiteiftheholeatthebottomgetsblocked.Pearlsgrowinpoolsofcalcite-richwaterlikeanoysterpearl.Theygrowlayeruponlayeraroundagrainofsand.Flowstonegrowswherewaterflowsoverwallsorfloors.Beardsareclumpsofdelicate,thinthreadsthatgrowfromwatercontainingdissolvedgypsum.Popcornformationsareclustersthatlooklikepopcornorgrapes.Theyarefoundonceilings,floors,andwallsofcaves.

SOMEFAMOUSCAVESOFTHEMIDWEST

Bear Cave, Michigan: named for skeletons of the extinct cavebear.

Bluespring Caverns, Indiana: contains the longest knownunderground river in the United States. It is 3 miles long (5kilometers).

BridalCave,Missouri:whereover2,000coupleshavemarried.

CaveoftheMounds,Wisconsin:itshugevarietyofspeleothems

includesodastraws,flowstones,andcavepearls.

Cave of the Winds, Colorado: its rare crystalline speleothemsincludecaveflowers.

FantasticCaverns,Missouri:hasatourthroughtheentirecaverninatram.

IllinoisCaverns,Illinois:manyofitsformationsarestillactivelygrowing.

Marengo Cave, Indiana: discovered in 1883 by two children,OrrisandBlancheHiestand,ages11and15.

MinnetonkaCave,Idaho:fivedifferentspeciesofbatshibernateinit.

OhioCaverns,Ohio:withthecolorfulJewelRoomthathasbeencalled“America’sMostColorfulCavern.”

WindCave,SouthDakota: known for itsboxwork,which is anunusual speleothemmadeof thin fins that look likehoneycombs.Wind Cave is near Jewel Cave, and the two caves may beconnecteddeepunderground. It isoneof theworld’s longest andoldestcaves.

DIDYOUKNOW?The longest known cave is Mammoth Cave inKentucky with a length of 390 miles (628kilometers). It’s also one of the oldest touristattractions in the United States. People have beengoingontoursofMammothCavesince1816.

WORDSTOKNOWspecies: a group of plants or animals that are relatedandlookthesame.

WORDSTOKNOWgranule:asmallgrainorpellet.

firn:granularsnowthathasnotyetbeencompressedintoice.

zone of accumulation: the area on a glacier where snowaccumulates.

gravity:theforcethatpullsobjectstotheearth.

GLACIERS:MASTERSCULPTORSMost of the northern plains have been transformed by the action of glaciers.Howdidglacierscomeso farsouth,andwhyaren’t theyherenow?First let’slookatglaciersandhowtheyform.

Whenmoresnowfallsthanmeltseachyear,itaccumulatesandeventuallyformsaglacier.

Snowflakeshaveabeautifulcrystalstructurethatisoftensix-sided.Atfirst,whensnowfalls,it’slightandfluffy.About80percentofitisair.Overtime,thesnowflakesloseairandcompress,becominggranules.Afteraboutayear,only50percentisairandit’scalledfirn.Withevenmoretime,thefirnmeltsslightlyandrefreezesandevenmoreair issqueezedout.Thesnowflakeshavebecomeglacialice.

Glaciers thickenwheremore snowaccumulates.This is called thezoneofaccumulation.When the ice grows thick enough it begins to move from theforceofgravity.

WORDSTOKNOWzoneofablation:theareaonaglacierwheresnoworicemeltsorevaporates.

Aglaciermovesintwoways.Thethinlayerofmeltedwateratthebaseofaglacier helps it slide along the ground. But it can alsomove from the inside.Because of the great weight of glaciers, pressure causes the ice crystals deepinsideaglaciertolineupintolayers.Theselayersslideagainsteachotherlikeadeck of cards. The ice can actually bend and flow, a bit like Silly Putty.Sometimesglaciersevenhavefoldsinside.Asaglaciermovesdownhill,itmelts

where it’s warmer. The area where the glacier melts is called the zone ofablation.

Whenmoresnowfallsatthezoneofaccumulationthanmeltsinthezoneofablation,theglaciergrows.Whenlesssnowfallsthanmelts,theglacier

shrinks.

Therearetwomaintypesofglaciers:alpineandcontinental.

Alpine glaciers are formed in valleys high in the mountains wheretemperaturesarecolder.TheRockyMountainshavealpineglaciers.

Continentalglaciersarehugeicesheetsthatcompletelycoverthelandofamajorpartofacontinent.Today,therearecontinentalglaciersonGreenlandandAntarctica.Butinthepast,continentalglacierscoveredmuchofnorthernNorthAmericaandnorthernEuropeandAsia.

DIDYOUKNOW?It actually takes longer to form glacial ice in very coldtemperatures.That’sbecauseit’ssocoldthatsnowdoesn’tmeltenough to refreeze into solid ice very quickly. A glacier inAlaskamight take 30 to 50 years to form.But inAntarctica,whereit’sextremelycold,itmighttakeaslongas3,500years!

WORDSTOKNOWPleistocene: theepoch ingeologichistoryfromabout2.5millionyears ago to 10,000 years ago that experienced repeatedglaciations.

IceAge:aperiodoftimewhenlargeicesheetscoverlargeareasofland. It particularly refers to themost recent series of glaciations

during the Pleistocene. An ice age can include shorter periodswhenglaciersretreat,aswellasperiodswhentheglaciersgrow.

glacialperiod:aperiodoftimewithinaniceagewhenalargepartoftheearth’ssurfaceiscoveredwithice.

interglacial period: a periodwithin an ice age that is somewhatwarmerandglaciersretreat.

ICEAGE!Earth’sclimategoesthroughnaturalvariationsintemperatureovertime.Thisisduetoacomplexinteractionofthedistancefromthesun,howEarthturnsonitsaxis,andwherethecontinentsare.

Inthelast2.5millionyears,untilabout10,000yearsago,therehavebeenatleast 11 major cycles of cooling and warming. This entire time is called thePleistocene, or sometimes just the Ice Age. During the cold periods,temperaturesdroppedovermany,manyyearsandglaciersexpanded.Thesearecalledglacialperiods.

Duringthewarmerperiods,calledinterglacialperiods,theglaciersshrank.DuringtheglacialperiodsoftheIceAge,about30percentofthelandonEarthwascoverediniceupto2milesthick(3kilometers).

InNorthAmerica,icecoveredthenorthernpartoftheMidwestandextendedasfarsouthassouthernIllinoisandcentralMissouri.

Themostrecentglacialperiodbeganabout100,000yearsago.ItiscalledtheWisconsinGlacialEpisode because you can see its effects best in the state ofWisconsin. Some of the key discoveries and the first map of the extent ofglaciationinNorthAmericaweremadeinsoutheasternWisconsin.

The Wisconsin glaciation lasted until about 10,000 years ago. Duringglaciations, thesea level fallsbecausewater isheld in theglaciers.During theWisconsinglaciation thesea level fellenough toexpose land linkingAsiaandAlaska and created a “land bridge.” Many scientists think that humans andanimals migrated across this bridge from Asia into North America sometimebetween 12,000 and 20,000 years ago. From Alaska, people then migratedthroughouttheAmericas.

No one knows whether the Ice Age is over or still going on. Interglacialperiods last about 10,000 to 12,000 years, and we’ve been in an interglacialperiodforaboutthatlong.Humaneffectsontheclimatecouldpossiblydelaythestartofanotherglacialperiod.

MaximumExtentofGlaciation

GLACIALLANDFORMSGlacierserode the landandreshape it.Whenglaciersmove, theirgreatweightcracksandcrushestherockbeneath.Theglacierplucksupchunksofrockandcarries them along. These chunks can vary in size from fine sediment calledrock flour to house-sized boulders. They are frozen into the ice and, as theymove, the rock chunks grind and polish the bedrock underneath—a bit likesandpaper.

WORDSTOKNOWrock flour: fine-grained sediment made from glaciers grindingoverbedrock.

grassland:alargeareaoflandcoveredwithgrass.

Whentheglaciermelts,itdepositsthismaterialintovariouslandforms.

Many of these effects of glaciers might be hard to recognize because thelandformsarecoveredoverbygrasslands,forests,andfields.Butlookbeyondthevegetationandyoumightseesomecluesthataglacierhasbeenaround.

Scratches and grooves in the bedrock: these are deep parallel scratcheswheretheglacierscrapedovergroundcarryingbrokenrock.

Glacialpolish:justlikeyoumightpolishbrasswithcleanerthathasabitofgritinit,glacierswithrockflourpolishtheunderlyingbedrock.Therockhasasmoothsurface,almostlikeglass.

Esker:whenaglacierhasariverflowingunderneath it, that riverdepositsmaterialjustlikeregularriversdo.Whentheentireglaciermelts,thedepositedmaterialformsameanderingridgeoftillcalledanesker.

DIDYOUKNOW?Iceisatypeofmetamorphicrock,whichisrockthathasbeenchangedbytemperatureandpressure.Itjusthappenstohavealowermeltingpointthananyotherrock.

Till:arandommixtureofclay,rocks,andgravel,whichiscarriedalongbyaglacierandthendepositedastheicemelts.

Moraines:depositsoftillthatformonthesidesandfrontofglaciers.Astheglaciermelts,thetillisdroppedoutintomoundsandridges.Terminalmorainestracethefarthestedgeofaglacier.

Erratic: a rock that has been carried by a glacier from another location.Erratics can be as small as a pebble or as large as a house. Scientists try todeterminewhereerraticscamefromtohelpthemmaptheflowdirectionsoftheglacier. You can find numerous erratics throughout Voyageurs National Park.OneerraticinAlberta,Canadaweighsover18,000tons(16,329metrictons)!

DIDYOUKNOW?Twiceinthelong-agopast—710and635millionyearsago—scientistsbelieveEarthwas covered in ice sheets, evenat theequator! Scientists call this the Snowball Earth Theory. Evenduringthisdeepfreeze,lifesurvivedintheformoftiny,single-celledmicrobes.

Drumlin: a smooth, teardrop-shapedmound thatwasmoldedbyaglacier.These often occur in groups and from above can look like a pod of whalesswimming. You can find drumlins at Isle Royale National Park, an island inLakeSuperior.

Kettle: a bowl-shaped depression. Kettles form when a block of ice isseparatedfromtheglacierandiscoveredbytill.Whentheicelatermelts,thetillcollapses intoabowlshape. InsoutheastWisconsin,KettleMoraine isanareawith numerous kettles. They are often filled with water, creating lakes andponds.Thekettlesformedwheretwolobesoftheglaciermetandlargeblocksoficebrokeoff.

DIDKNOWYOUMinnesota iscalled theLandof10,000Lakes,althoughithasevenmore than that.Most of those lakes formedwhenwaterfilledinkettlesleftbyretreatingglaciers.

WORDSTOKNOWlobe: an extension of a glacier, with a shape like a tongue. TheWisconsinglaciationhadsixmajorlobes.

ICEAGENATIONALSCENICTRAIL

The Ice Age National Scenic Trail covers 1,200 miles throughWisconsin (1,931kilometers). It traces theedgeof theWisconsinglaciation,highlighting landscape features from the IceAge.Youcan see moraines, eskers, erratics, kettles, drumlins, and more—probablybetterthananywhereelseonEarth!Othernationalparkswhere you can find evidence of glaciation in the Midwest areVoyageurs National Park inMinnesota and Isle Royale NationalParkinMichigan.

DIDYOUKNOW?Glaciers often have a bluish or greenish tint becausemost oftheairhasbeensqueezedout.

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MAKEYOUROWNKETTLES

SUPPLIESshallowpansandordirticecubeswater

Fill the pan about½ inch deepwith sand (1 centimeter). Set several icecubesintothesandwithatleast2inchesbetweencubes(5centimeters).

Fill in thespacesbetween thecubeswith sand.Keepaddingsanduntil itcoverstheicecubeswithabout¼inchofsand(½centimeter).Thetopof

thesandshouldbelevel.Sprinklewateronthesanduntilit’sdamp.

Waitanhourorso.Whatdoesthesurfaceofthesandlooklike?Tryslowlyaddingmorewater.Doesitfilltheholes?

WHAT’SHAPPENING?Theicecubesarelikepiecesofaglacierthathasbrokenoff.Thesandislikethetillcoveringthepiecesofglacier.Whentheblockofglaciermelts,thetillcollapsestoformabowlordepressionintheland.Thesearecalledkettles,

andtheyoftenfillwithwatertoformlakesandponds.

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MAKEYOUROWNNEEDLE-LIKECRYSTALS

SUPPLIESblackcardstockorconstructionpaperscissorsshallowcookiesheetorpiepan1cupEpsomsaltsfromthepharmacy(240grams)1cuphottapwater(250milliliters)spoonfoodcoloring(optional)

Cut thepaper intowhatevershapeyoulike,suchasasnowflakeorheart.Place the paper on the cookie sheet. The paper needs to fit completely

withinthecookiesheet.

Slowlypour theEpsomsalts into thehotwater, stirring constantly.Keepstirring until all of the Epsom salts are dissolved, if possible. Add food

coloringifyoulike.

Pourthesolutionoverthepaper.Placethecookiesheetwiththepaperandsolutioninawarmplace, likeasunnywindow.Withanadult’shelp,you

can alsoplace the cookie sheet in awarmoven (200degreesFahrenheit/93

degreesCelsius)for15minutesorso,butwatchittomakesureitdoesn’tdryouttoomuch.Youshouldstarttoseelotsoflarge,spikycrystalsgrowing.

WHAT’SHAPPENING?Likelimestoneandgypsum,epsomiteisamineralthatdissolvesinwater.Ithasanappearancethatlookslikelongthreads.Epsomitecanbefoundonthe

wallsofsomelimestonecaves,suchasMarengoCaveinIndiana.

T

CHAPTER5

CLIMATEheGreatPlainsarehometosomeof themostviolentstormsonEarth.Farfromtheoceans,theplainsandmountainsareoftenabattleground

betweenbigmovementsofcoldandwarmair.Thismakesforextremesintemperaturesandhugestorms.Let’stakealookaroundtheregiontofindoutwhyithassuchinterestingweather.Butholdontoyourhat—it’swindyoutthere!

WORDSTOKNOWcontinental climate: the climate found in the middle of acontinent.Itischaracterizedbylargevariationsintemperatureandfourseasons.

HOT,HOT,HOT…THENCOLD,COLDIfyoucouldstand in themiddleof theGreatPlainswithno limitsonhowfaryou could see, you would notice a few things. First, you’re about halfwaybetween the equator and the North Pole. This is called a temperate zone. Itmeans that theweathervariesquiteabit fromseason to season,withbothhotandcoldweather.

Next,you’dnoticethatyou’refarfromanyoceans.Whatdoesthathavetodowithclimate?Waterheatsupandcoolsdownmoreslowlythanrockorsoilorplants.Thetemperaturesoflargebodiesofwaterliketheoceansdon’tchangeasmuchbetweenwinterandsummeraslanddoes.Soareasnearoceansdoesn’thaveasmanyextremesintemperature,especiallyifwindstendtoblowfromtheoceanontotheland.

But regions far from oceans have large variations in temperature betweensummerandwinter.TheMidwesthasthelargestannual temperaturevariationsoutsideofAlaska.Eventhoughwinterscanbedeeplycold,summerscanalsobeblisteringhot.Thisiscalledacontinentalclimate.

WORDSTOKNOWtornado: a violent, twisting, funnel-shaped column of airextendingfromathunderstormtotheground.

blizzard:aseveresnowstormwithhighwinds,lowtemperatures,andheavysnow.

Whichcitywouldyouguesshashadthehottesttemperature:Miami,Florida,orBismarck,NorthDakota?Areyou surprised thatMiamihasnever recordedtemperaturesabove100degreesFahrenheit(38degreesCelsius)?Bismarck,onthe other hand, reached 114 degrees Fahrenheit in July 1936 (45 degreesCelsius).Butonaverage,NorthDakotaisthesecond-coldeststate,rightbehindAlaska.Howcanthisbetrue?Lookonamapandseehowfareachcityisfromtheocean.

Finally,you’dnotice that for a longway, the land isvery flat.To theeast

you’d see the Appalachian Mountains, and to the west you’d see the RockyMountainsrisingsharplyfromtheplains.Thewaythemountainsandplainsarearranged affects themovement of large bodies of air. Itmakes the region thehomeoflargethunderstorms,tornadoes,andblizzards.

TEMPERATUREEXTREMESInternationalFalls,Minnesota,locatedinthefarnorthofthestate,iscalled“TheIceboxoftheNation.”Itcangetmightycold,witharecord low temperature of -58 degrees Fahrenheit (-50 degreesCelsius). With temperatures that cold, you might think it neverwarmsup.Butwithitscontinentalclimate,InternationalFallshasarecord high temperature of 103 degrees Fahrenheit (39 degreesCelsius).Thedifferenceinaveragetemperaturesbetweensummerand winter there is almost 89 degrees Fahrenheit (31 degreesCelsius).

STORMCOMINGTHROUGH!Haveyoueverheardsomeonesaythatastormfrontiscomingintothearea?Alarge,movingpocketofairiscalledanairmass.Whenawarm,moistairmasscollideswith a cold, dry airmass, the areawhere theymeet is called a front.Stormsoftenoccuralongfrontsbecausetheairthereisunstable.

DIDYOUKNOW?A blizzard stormed across Minnesota, Wisconsin, Michigan,Nebraska,andSouthDakotaonNovember11,1940.Windsof80milesperhour(129kilometers)driftedsnowashighas20feet(6meters)!

IntheMidwest,warm,moistairsweepsinfromtheGulfofMexicointhesouthbecausetherearenomountains toblocktheair.Colder,dryaircomesinfromthenorthandwest.When these twoair systemsmeet, lookout! In thewinter,snowstorms can quickly turn into blizzards. In the summer, toweringthunderstormsform,sometimesspawningdestructivetornadoes.

SOMEEVILNOVEMBERWITCHES

Inthefall,theGreatLakesstillhaveheat,sincetheselargebodiesof water cool downmore slowly than the surrounding land. Theheat adds power to snowstorms, fueling high winds and waves.Sometimes, twoormorestormscollideover theGreatLakesandformasuperstorm,especially in the late fall.When thishappensit’scalleda“Novemberwitch.”Twoespeciallybadoneswerethefollowing:

ANovemberstormin1975sankahugefreightercalledtheSSEdmund Fitzgerald on Lake Superior. All of the crew died.It’s the largest ship to have sunk in the Great Lakes,measuring 730 feet long (222 meters). Gordon Lightfootcommemoratedthesinkingina1976hitsong“TheWreckoftheEdmundFitzgerald.”AblizzardragedacrosstheGreatLakesfromNovember7to

November10,1913.Thestormhadwindsof60 to90milesperhour(97 to145kilometers)andwavesover35feethigh(11meters).Itdestroyed19shipsandcausedover250deaths.

WORDSTOKNOWjet stream: a high-speed flow of air high in the atmosphere thatflowsfromwesttoeastandoftenbringsweatherwithit.

BLIZZARD!Ablizzardisanintensesnowstormwithverylowtemperatures,lotsofblowingsnow, and high winds. These storms often bunch up around the RockyMountainsortrackovertheGreatLakes.

The jet stream is another reason the Midwest gets intense wintertemperaturesandstorms.Ithasnothingtodowithplanes,butajetstreamdoestravelfast.Thesenarrowcurrentsofairhighabovethesurfaceoftheearthtravel

asfastas250milesperhour(400kilometers).

Weathersystems,suchasstorms,oftenfollowjetstreams,whichact likea“highway” for storms. Jet streams also follow boundaries between warm andcoldair.There’sajetstreamaboveCanadathattravelsfromwesttoeastmostofthetime.Itmeandersnorthandsouthlikeariver,butisusuallytothenorth.Inthewinter the jet streammoves south, bringingwith it cold, dry air from theArctic.

WORDSTOKNOWwind shear: a change in the direction of wind, especially whenwindblowsindifferentdirectionsatdifferentheights.

supercell: a severe thunderstorm with strong updrafts anddowndrafts of air. Supercells often have large hail, strongwinds,downpours,andsometimestornadoes.

condense:tochangefromagastoaliquid.

TORNADOES!Tornadoescanbreaka tree inhalf,smashahouse,orevenmovea traindownthe tracks!Theyare themostviolent stormsonEarth. Insidea tornado,winds

twistupwardinafunnel-shapedcolumnanywherefrom90to300milesperhour(145 to 483 kilometers per hour)! Tornadoes are most likely to occur in theUnited States in the months of April, May, and June, in the heat of the lateafternoon.About1,000tornadoesarereportedeachyear.

Tornadoesoccurallovertheworld,buttherearemoretornadoesintheUnitedStatesthaninanyothercountry.

Atornado,alsocalledatwister,oftentravelsinacurvedpath,anditcanbehardtopredictwhichwayitwillgonext.Itusuallymovesoverlandatabout30milesperhourorless(48kilometers),butsometimesfaster.Itcanlastforonlyafewseconds,orforhours.Tornadoescanlooklikeathinneedleorabowl.Eachoneisdifferent,butthey’reallpowerfulandpotentiallydangerous.

HOWDOTORNADOESFORM?A tornado starts withwind shear. This is when the wind blows in differentdirections at different heights. For example, the wind at the groundmight bemovingnorth,while thewindhigherup ismovingsouth.Thisdifference rollsthe air in between into a spinning tube,much like you roll claybetweenyourhands.There canbea lotofwind shear in late spring,making this the “high”seasonfortornadoes.

Windshearbyitselfwon’tcreateatornado.Itneedslotsofenergytoo.Thiscancomefromahuge,powerfulthunderstorm—thekindwithdark,almostblackclouds, lightning, and sometimes hail. These large thunderstorms, calledsupercells, formwhenwarm,moist air slams into cold, dry air.Themoist airrises through the cold air, and as it cools, themoisture condenses and formsclouds.Asmorewarmair rises andpumps energy into the system, the cloudsturnintothunderstorms.

Therisingairinthethunderstormliftsthetubeofspinningairintothestorm.When the twisting tube of air tightens and spins down to touch the earth, a

tornadoisborn.

WORDSTOKNOWEnhanced Fujita scale: a scale used to measure the strength oftornadoesbasedonthedestructiontheycause.ThescalerunsfromEF-0toEF-5,withEF-5beingthestrongest.

hail:ballsoficeandfrozensnowthatfalllikerain.

HOWBADISIT?Tornadoes are ratedon a scale called theEnhancedFujita scale. It is namedafterTheodoreFujita,whofirstdevelopedasimilarscale.TheEnhancedFujitascalewasimplementedin2007andrunsfromEF-0toEF-5.Scientistsusuallycan’t measure the speed of the winds within most tornadoes, but they canestimatethewindspeedbasedonthedamageatornadocauses.

Scale WindSpeed TypicalDamageEF-0 65to85mph(105to

137kph)Treelimbsandchimneysbroken,someroofsdamaged

EF-1 86to110mph(138to177kph)

Roofspeeledoff,windowsbroken,carsoverturned

EF-2 111to136mph(179to219kph)

Roofscompletelytornoff,largetreesuprooted,carsliftedoffground,mobilehomesdestroyed,foundationsofhomesshifted

EF-3 137to165mph(221to267kph)

Partsofhousesandlargebuildingsdestroyed,trainsoverturned,largecarsthrown

EF-4 166to200mph(269to322kph)

Housesflattened,carsandstructuresthrowngreatdistances

EF-5 Greaterthan200mph(324kph)

Completedestructionwithhousessweptawayandcompletelydestroyed,high-risebuildingsbadlydamaged,carsliftedsotheyflythroughtheair,trainsliftedofftracks

TORNADOALLEYThe Midwest has more tornadoes than any other region in theUnited States because of its intense supercell thunderstorms andwindshear.Andwherethere’sasupercell thunderstorm,there’sagoodchanceitwillspinoutatwister!

ThemiddlepartofAmericaiscalledTornadoAlleybecauseithassomanytornadoes.Thisareadoesn’thaveanexactdefinition,butgenerally includes most of the states of South Dakota, Iowa,Nebraska, Kansas, Oklahoma, Texas, parts of Colorado, andMinnesota. But some people also include other states, fromMichigan to Louisiana and east to Ohio. Florida also has many

tornadoes,buttheyarenotasintense.

WHATTODOWHENTHEREISATORNADO

Whentheweatherforecastwarnsoftornadoes,youneedtopayattention.Listento the radio or TV for more information. And look for signs of bigthunderstorms, like a very dark, often greenish sky or largehail. If there is atornado warning, be prepared to take shelter. This means finding a sturdystructure,preferablywithabasement.Don’tstayinamobilehome.Alowlying,darkcloudthatmightbeswirlingoraloudroararestrongwarningsignsthatatornadoiscoming.

KILLERTORNADOESTheseweresomeofthemostpowerfulanddevastatingtornadoes:SuperOutbreak: The largest outbreak of tornadoes recorded inone24-hourperiodoccurredfromApril3toApril4,1974,calledtheSuperOutbreak.Therewere148documented tornadoes in13states on that day.Many of these tornadoes were violent. Therewere six F5 tornadoes and 24 F4 tornadoes (measured on theoriginalFujitaScale).Altogether,330peoplewerekilledand6,142wereinjuredbythetornadoes.

TheTri-StateTornado:OnMarch18,1925,thesingledeadliesttornadoinUnitedStateshistorykilled695people.It tore throughMissouri,Illinois,andIndiana,leaving15,000homesdestroyed.InthetownofGorham,Illinois,everysinglebuildingwasdestroyed.

The Greensburg Tornado: On May 4, 2007, this tornadocompletely destroyed the town of Greensburg, Kansas. Luckily,meteorologists were able to give residents a 20-minute warningusing tornado sirens, so people could get to shelter underground.But hail fell the size of golf balls andwinds over 200miles perhour roared like a jet engine (322 kilometers per hour). TheGreensburgTornadocrushednearlyeverybuildinginthetown.

WORDSTOKNOWmeteorologist: a scientist who studies and forecasts climate andweather.

If you’re near a safe structure (a well-built home, school, or hospital) getinsideimmediately.Gotoabasementifpossible.Otherwisegotothefirstfloor,

asfarawayfromwindowsaspossible,likeinahallorinsidecloset.Donotopenwindows. Crouch down and cover your headwith your arms.Get underneathmattressesorheavyblanketsifyoucan.

Definitely leavea car immediately.Try toget toa safe structure,but evenbeingoutintheopenisbetterthanacar.Ifyoucan’tgettoasafestructure,lieflatinaditchorlowlyingarea.Coveryourheadwithyourarms.Don’tgetunderabridgeorroadoverpass.Asscaryastornadoescanbe,ifyouknowwhattododuringatwister,itcanmakeabigdifference.

MOUNTAINWEATHERMountainsliketheRockieshavetheirowndistinctiveweather.They’reusuallymuchcolderthanthesurroundingcountry.Theweathertherecanchangeoften,andhaveheavierprecipitation.

Altitudehasahugeinfluenceontemperature.Thehigheryougo,thecolderitbecomes.Thisisbecausetheatmosphereactslikeablankettokeepheatin.Athigherelevations,the“blanket”isn’tasthickandheatescapes.That’swhymanyhighmountainsliketheRockiesarealwayscoveredinsnow.Itnevergetswarmenoughupthereforthesnowtocompletelymelt,eveninthesummer.

WORDSTOKNOWprecipitation: the falling to earth of rain, snow, or any form ofwater.

altitude:theheightabovesealevel.Alsocalledelevation.

DIDYOUKNOW

Rocky Mountain National Park in Colorado is high inelevation, so it can snow there even in July! The parkfrequently experiences hurricane-force winds during winterstorms.Oneblastofwindwasmeasuredat201milesperhour(323kilometers)!

Ifyou travelwest fromDenver,Colorado,anddrive less thananhourintotheRockyMountains,thetemperaturecandrop30degreesFahrenheit(17degreesCelsius)ormore!

RAINSHADOW

Thewestern side of the RockyMountains receives on averagemore rain andsnow than the east side. Why? Weather systems in the western half of thecountrymoveinfromthePacific,fromwesttoeast.AswarmairpassesoverthePacificOcean, itpicksupmoisture.Whenmoistairencountersmountains, theairisforcedupalongtheslopes,wheretherisingaircools.Sincecolderaircanholdlesswatervaporthanwarmerair,thewatervaporintheaircondensesinto

tinydropletsandformsclouds.Haveyouevernoticedcloudscoveringthetopsofmountains?Ifenoughwatervaporcondensesintodroplets,itrains.

DIDYOUKNOW?People often get weather and climate confused. Weather iswhat happens in the atmosphere related to temperature,precipitation,winds,andclouds.Climateistheaverageweatherofaplaceoveralongperiodoftime.

Astheairmovesdowntheothersideofthemountains,itwarms.Theairhasalreadylostsomeofitsmoisturefromraining.Andnowitcanholdmorewatervapor because it is warmer. So the far side of the mountains, called a rainshadow,getsmuchlessrainfall.

Before weather systems even get to the Rockies, the air has already lostmuchofitsmoistureasitpassesovermountainsalongthePacificcoast.ThisiswhyeventhewesternsideoftheRockiesisn’tthatwet.Buttheeasternsideisevendrierbecauseit’sintherainshadowoftheRockies.

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MAKEYOUROWNCONTINENTALCLIMATE

SUPPLIES2largeStyrofoamcups,thesamesize1cupofsand(200grams)water2thermometers

Fillonecupabouthalffullwithsand.Fill theothercuptothesamelevelwithwater.Placethethermometersuprightintothewaterandsand.Make

suretheendsofthethermometersarefullysubmerged.

Waita fewminutes, thencheck the temperatureof thesandandwater. Iftheyaren’tthesame,adjustthewatertemperaturebyreplacingsomeofthe

waterwithwarmeror colderwateruntil the temperatures are equal.Recordthetemperatures.

Placebothcupsonasunnywindowsillorunderastronglight.Makesurethecupseachreceivethesameamountoflight,andthelightdoesn’thitthe

bulb of the thermometers directly. Record the temperatures about every 10minutes.Afteraboutanhour,turnthelightofformovethecupstotheshadeandletthemcool.Recordthetemperaturesaboutevery10minutes.

WHAT’SHAPPENING?Landheatsupandcoolsdownfasterthanlargebodiesofwaterlikeoceans.Sointhewinter,airovertheoceantendstobewarmerthanairoverland.Inthesummer,thereverseistrue.Whenseabreezesmoveontolandinthesummer,theycooltheland.Inthewinter,theywarmtheland.Thishastheoveralleffectofkeepingtemperaturesmoderateforcoastalareas.Butlandintheinteriorofthecontinent,liketheGreatPlainsandRockyMountains

region,hasbigswingsbetweenwinterandsummer.

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MAKEYOUROWNTORNADOINABOTTLE

SUPPLIES•2clear,2-literplasticsodabottleswithoutdentscoldwaterafewtablespoonsofvegetableoilsmallbowlfoodcoloring1-inchmetalwasher(2½centimeters)ducttapestopwatchorclockwithasecondhand

Removealllabels,caps,andtheplasticringsonthemouthsofthebottles.Fillonebottleaboutthree-quartersfullwithcoldwater.

Pourtheoilintothesmallbowlandaddthefoodcoloring.Stir.Thenaddthemixturetothewaterinyourbottle.

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6

Place the washer on top of the bottle’s mouth. Turn the second bottleupsidedownandplaceitontopofthefirstbottle.Themouthofthesecond

bottleshouldbelinedupwiththewasherandthemouthofthefirstbottle.

Get a friend to hold the bottles steady while you firmly wrap duct tapearoundthemouthsofthebottles,goingaroundseveraltimes.Presstheduct

tapetightlyagainsttheplasticsothatitwon’tleak.

Grabthebottleswheretheyarejoinedandquicklyturnthemupsidedownsothatthewaterisinthebottleontop.Quicklyswirlthebottlesarounda

fewtimesincircles.

When all thewater has drained into the lower bottle, repeat step5. Thistime,trytimingittoseehowlongittakesforthewatertodrain.Thenflip

the bottles again but do not swirl the bottles around. Does the water drainfasterorslowerwhenyouswirlit?

WHAT’SHAPPENING?Doyouseeafunnelintheoilandwaterasitflowsfromthetopbottleintothebottom?Thisislikethefunnelthatformsinatornado,exceptit’sliquid.Forthewatertodrainintothelowerbottle,theairinthelowerbottlehastoalsomoveintothetopbottle.Theyhavetotradeplaces.Whenyouswirlthewaterintoafunnel,there’saholeinthemiddlesothattheaircanmoveupwardat

thesametimethewatermovesdownward.

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CHAPTER6

RIVERSheBigMuddy.TheFatherofRivers.Thesearebignamesforbigrivers.The Great Plains andMountainWest region contains the headwaters

and the main section of the greatest river system in North America: theMissouri-MississippiRiversystem.

WORDSTOKNOWheadwater:ariver’ssource.

tributary:astreamorriverthatflowsintoalargerriver.

watershed:thelandareathatdrainsintoariverorstream.

Thewater inriverscomesfromprecipitationthatflowsover thesurfaceof theland. Smaller creeks and streams flow together and form bigger streams andrivers. They are called tributaries of the river they flow into. The land thatdrainsintoariveristhewatershedofthatriver.Mostriversflowintotheocean.

HOWLONGISIT?WhenpeoplesaytheMississippiRiver,theyusuallymeantheriverthatstartsinMinnesotaandendsattheGulfofMexico.Itis2,320miles long (3,734 kilometers). Sometimes, especially whencomparingthesizeofriversintheworld,peoplemeantheMissouriRiver and its tributaries, aswell as the LowerMississippiRiver.TheMissouri-MississippiRiversystemtotals3,745mileslongandisthethird-longestriversystemintheworld(6,027kilometers).

TheUpperMississippiisthepartoftheMississippiRiverfromitsheadwaters inMinnesota towhere theOhioRiver joins atCairo,Illinois. The LowerMississippi is the part of the river from thispointtotheGulfofMexico.

NearlyalltherainthatfallsintheGreatPlainsandMountainWestregioneventuallydrainsintotheMissouriandMississippiRivers.

MISSISSIPPIRIVERTheMississippiRiver issometimescalled theFatherofRivers.This isagoodnickname. It is the largest river in theUnitedStatesby theamountofwater itcarriesandthesecond-largestbylength.Includingitstributaries,theMississippiRiver is the largestriversysteminNorthAmerica. Itdrains31statesfromtheAppalachianMountains in the east to the RockyMountains in the west, andnorthtoCanada.

IfyoulookatamapoftheMississippianditstributaries,itlooksabitlikeatree.ThetrunkstartsinMinnesotaandendsinLouisianaattheGulfofMexico.Itsbigbranchesarethelargerivers,ortributaries,thatflowintotheMississippi.ThesearetheMissouriandIllinoisRiversthatdrainintotheUpperMississippi,andtheOhio,Arkansas,andRedRiversthatdrainintotheLowerMississippi.

WORDSTOKNOWmigratorybird:abirdthatmigrates.

confluence:thepointwheretwoormorestreamsflowtogether.

prairie: the wide, rolling land covered in grasses, west of theMississippiRiver.

The Mississippi starts in the cold waters of Lake Itasca in northernMinnesota. After flowing through Minnesota, it forms part of the boundarybetween several states, including Minnesota, Iowa, Missouri, Arkansas, andLouisiana on the west, and Wisconsin, Illinois, Kentucky, Tennessee, andMississippiontheeast.

TheMississippiRiverishometoahugevarietyofwildlife.Thereareabout240 different kinds of fish in the Mississippi, along with about 50 differentmammals living in and around the river. Northern areas are home to wolves,moose,blackbears,andsnowyowls.TheUpperMississippiRiverRefugerunsfor261milesalongtheriverthroughthestatesofMinnesota,Wisconsin,Iowa,and Illinois (400 kilometers). It’s a protected area formigratory birds, fish,wildlife,andplants.Thereareover250nestsforbaldeagleswithintheRefuge!

MISSOURIRIVERTheMissouriRiver begins in theRockyMountains in northwesternMontana.It’sthelongestriverinNorthAmerica,drainingawatershedfrom10states.

TheMissouriRiverbeginsat theconfluenceof theGallatin,Madison,andJefferson Rivers in Three Forks, Montana. It then flows 2,540 miles (4,088kilometers)throughcanyonsandprairiesuntilitjoinstheMississippiRiverjustnorthofSt.Louis,Missouri.TheYellowstoneRiverisitslargesttributary.

Numerous cities have grown up along the Missouri River. These includeBismarck in North Dakota, Pierre in South Dakota, Omaha in Nebraska, andSiouxCityinIowa.TheMissouricitiesofKansasCity,JeffersonCity,andSt.LouisarealsoallontheMissouriRiver.

WORDSTOKNOWdam: a large, strong wall built across a river to hold back andcontrolthewater.

reservoir:anareathatholdswaterbehindadam.

The Missouri River was called the Big Muddy in years past because itcarriedsomuchsoil.Onesayingwasthat“amanjumpingintotheMissouriismoreapttobreakalegthandrown.”Itwasapowerfulriverthatfloodedoften

anderodedsoil.Nowtheriveriscontrolledbydams,built topreventfloodingand providewater for crops. Thewater ismuch clearer because the sedimentsettlesoutinthereservoirscreatedbythedams.

LEWISANDCLARKMeriwetherLewisandWilliamClarkwere the firstUnitedStatescitizenstotraveltheentireMissouriRiver.TheMissourihadbeenexplored by native peoples and French explorers before, but thiswas the first systematic mapping of the river. Lewis and ClarkstartedfromSt.LouisonMay14,1804,wheretheMissourijoinstheMississippiRiver.TheyreachedthesourceoftheMissourionJuly25,1805,atThreeForks,Montana.

OTHERRIVERSTherearemanyotherimportantriversinthemiddleofthecountry.SeveraldrainintotheMissouriandUpperMississippiRivers.

WORDSTOKNOWcanal:aman-madewaterway.

barge:aboatwithaflatbottomusedtocarryloadsoncanalsandrivers.

The Yellowstone River is the longest undammed river in the continentalUnited States. It runs for 692 miles (1,114 kilometers), beginning nearYellowstoneNational Park in northwesternWyoming. TheYellowstone flowsthroughMontanaandjoinstheMissouriRiverinNorthDakota.Itisknownforitstroutfishing.

The Illinois River flows through the state of Illinois for 273 miles (439kilometers), joining the Mississippi River just north of St. Louis, Missouri.Canals connect the IllinoisRiver toLakeMichigan, providing a linkbetweentheGreatLakesandtheGulfofMexico.Barges transportgoodssuchasgrainandoilalongtheIllinois.

The Platte River flows for 1,026 miles before flowing into theMissouriRiver (1,651 kilometers). The North and South Platte Rivers both start inColorado.TheNorthPlatteflowsthroughWyoming,thenjoinstheSouthPlattein Nebraska to form the Platte. It drains amajor portion of the central GreatPlains.ThePlattehasbeencalled“amilewideandaninchdeep”becauseitissowideandshallow.Severalhundredthousandsandhillcranesvisit thePlatteforfourtosixweekseachspringontheirmigrationnorthtoCanada.

DIDYOUKNOW?Allupanddown theMississippi, largebarges transport cropsdowntheriver.Bargesaremoreenergyefficientthantrucksoreventrainsfortransportinglargeloadsofgoods.Theyrequireless than one third asmuch fuel as a truck per ton of goodscarried. One barge can carry 3,500 tons or more—that’s asmuchas134largesemi-tractortrailertruckscancarry!

WORDSTOKNOWsteamboat: a boatwith apaddlewheel that is turnedby a steamengine.

steamengine:anenginethatburnswoodorcoaltoheatwaterandcreatesteam.Thesteamgeneratespowertoruntheengine.

port:aplacewhereshipscanloadandunload.

STEAMBOATSBefore steamboats, river travel was just one-way: downriver on the current.People transported goods downriver on rafts.When they got to the end, theywouldtaketheraftsapartandsellthelogs.Goodscouldn’tbeshippedupriver.Inthe1800s,steamboatswereinvented.Alargepaddleat thebackof theboatwas turned by a steam engine. These steamboats carried people and goodsupriverallthewaytoMinnesota,andbackdownaswell.

Manysteamboatshadluxuriousaccommodationsfortheirwealthierpassengers.Therewerebeautifulcarpets,crystalchandeliers,andfancy

dinnersonboard.

Each steamboat had a distinctive bell that rang out at various times,

includingwhenitwastimetoleaveport.Thebellswereoftendecorated.Later,steamwhistles came into use aswell. Boats passing each other going up anddown the river had codes for which boat would go which way. Two whistleblastsmeanttheboatwouldgoontheleft.Onewhistleblastmeantitwouldpasson the right.Manypeoplecould recognizeaboatby itsbellor theblastof itssteamwhistle.

OL’MANRIVERShow Boat is a famous musical about the lives of people whoworkedonalargeMississippiRivershowboat.Ashowboatwasabargethathadplays,music,andotherentertainment.ShowBoat’smostwell-knownsongis“Ol’ManRiver”withthechorus:

Ol’manriver,datol’manriver,

Hemus’knowsumpin’butdon’tsaynuthin’

Hejes’keepsrollin’

Hekeepsonrollin’along.

RIVERPIRATESFrom the late 1700s to mid-1800s, pirates roamed the Mississippi and OhioRivers.Theyhid incavesandswamps.Pirates luredboatsbycallingoutas iftheywereintrouble.TheSamuelMasonGangkilledtheirvictims,thentossedthemintotheMississippiRiver.

Iftheytossedinmorethanonebody,theywouldplacebetsonwhichwouldhitbottomfirst.

The SamuelMason Gang was among the worst for about 20 years. TheyusedCave-in-Rock,alargecaveontheIllinoissideoftheOhioRiver,astheirbase.Masonwasoncediscoveredholding$7,000andabout20scalps!

DIDYOUKNOW?If you have a hankering for something tasty, you can tryvisitingtheserivers.

TheBlueberryRiverinMinnesota

TheFryingpanRiverinColorado

TheAppleRiverinWisconsin

TheAppleRiverinIllinois

TheArtichokeRiverinMinnesota

FLOOD!Rivers give life to the land, but they can alsobedestructive.A flood iswhenwater covers land that is usuallydry.Floodsusuallyhappenbecauseofheavyrainorsnow,whenthewaterlevelsinastreamorriverrisehighenoughtoflowoveritsbanks.

TheMissouri andMississippi Rivers normally overflow their banks everyfewyears.Thearea that thewateroverflowsonto iscalled thefloodplainofariver.Afloodplainhasrichsoilforfarming,andprovidesimportanthabitatforwildlife.Butregularfloodingcandamagefarmsandhousesinfloodplainareas.

Beginning in the 1800s, the government began altering the flow of theMississippiandMissouriRivers.TheU.S.ArmyCorpsofEngineersworkedtotametheriverandusetheenergyfromitsflowtogenerateelectricity.Theybuiltleveesanddugoutthechannelinplacestomaketheriverdeeperforboats.Thatwasfollowedbytheconstructionofdams.

WORDSTOKNOWfloodplain: theflat landnexttoariverthatfloodswhentheriveroverflows.

levee: awall of earth or stone built along a riverbank to preventfloodingoftheland.

MARKTWAINOneofAmerica’smostfamouswriterswasMarkTwain,whowasariverboatpilotasayoungman.Twainwasbornin1835withthename of Samuel Clemens, but used the name Mark Twain for

writing.Riverboatworkerswouldcallout“MarkTwain”whentheriver was a depth of two fathoms, which is about 12 feet (3½meters). His two most famous books, The Adventures of TomSawyerandTheAdventuresofHuckleberryFinn,aresetinarivertownandontheMississippiRiver.

Butfloodsstilloccur.Andalthoughthechangestotheriverpreventfrequentflooding,thosechangescanmakebigfloodsevenworse.Becausetheriverisn’tallowed to overflow onto its natural floodplain, all of that extrawater is keptinsidethechannelsandthewaterlevelrisesevenhigher.

DuringtheMississippiRiverFloodof1927,theriveroverfloweditsleveesin145placesin11states.Thefloodingkilled246peopleandcaused$400

millionindamages.

FromApriltoOctober1993,theMissouriandMississippiRiversfloodedallalongtheirbanksinninestates.CalledtheGreatFloodof1993,itwastheworstfloodingdisastersince1927.Morerainandsnowthannormalfellfromthefallof1992throughspring1993.Itcouldn’tallsoakintothegroundsoitfilledtherivers.Whenmoreraincameagaininthesummer,theriversfloodedagainandagain. St. Louis had river levels 20 feet above normal (6meters), the highestrecorded in 228 years. If it had risen 2 feet higher (½meter), it would havefloodedthedowntown.

Inall,100,000homesweredestroyedand50peopledied.Fourtownswerecompletely destroyed. Even though the 1993 flood had only the third-largestvolumeofwaterdischargeofallfloods,thewaterlevelwasthehighestbecauseofthelevees.

DIDYOUKNOWLevees are artificial riverbanks to prevent the river from

overrunning its banks. They control the direction the rivertakes. Levees have been constructed along theMississippi toprovide protection from floods and keep the river in itsmainchannel.There aremore than1,600milesof levees along theMississippi—that’slongerthantheGreatWallofChina!

TheMissouriandMississippiFloodsof2011camelessthan20yearslater.Duringthewinterandspringof2011,recordlevelsofrainfallandsnowfallfellinthewatershedsoftheMissouriandMississippiRivers.BoththeMissouriandMississippiRiversexperiencedsomeoftheworstfloodsinrecordedhistory.

TheMississippiRiverhadrisensohighthatitthreatenedtodestroytheleveesystem and flood towns, including Cairo, Illinois. The U.S. Army Corps ofEngineershadtoactquickly.Forthefirsttimein74years,theyblasteda2-mile-widehole(3kilometers)intheleveeattheBirdsPoint-NewMadridFloodwayinsoutheasternMissouri.Thisreleasedsomeofthewaterandloweredthelevelsin the main river to relieve pressure on the downstream levee system. Manypeople were unhappy because, although it saved a number of downstream

communities,italsofloodedfarmland.

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MAKEYOUROWNFLOOD

SUPPLIESlargemetalbakingpanortraybrickorwoodenblocksandorsoilwaterhoseconnectedtooutsidefaucetspoon

Choose a location outside to set up your experiment. It should bewithinreachofthewaterhoseandinaplacethatisokaytogetwet.

Setoneendofthepanontopofthebrick.Fillthepanwithsandorsoiltojust below the rim.Using the spoon, scoop out a channel in the sand. It

shouldstartattheraisedend,firstgoingstraightfor2inches(5centimeters),thenbending in a stretched-out “S” shape.This is your streamchannel.Ononebendinthestream,buildupthesandsomewhataroundthebanks.

Setthehoseatthetopofthestreamchannelandturnthewateronsothatthere isasmallstreamofwatergoing into thechannel.Let thewater run

forafewminutes.

4Slowly increase the water flow until it begins to overflow the channel.Wheredoesthewateroverflowthechannel?Turnoffthewaterandrebuild

thebanksindifferentways.Whathappensifyoubuildhighbanksalongtheupperhalfofthestream?Whathappensifyoumakeabreakinthehighbanksinoneplace?

DIDYOUKNOWSomeriversareprivateandsomearepublic.Bylaw,riversthatarelargeenoughtobenavigatedbycanoeandkayakareownedbythepublic(thatincludesyou)uptothehighwatermark.

WHAT’SHAPPENING?EngineershavebuiltupleveesalongpartsoftheMissouriandMississippiRivers.Thishaschangedhowoftenandwherefloodsoccur,justlikeinyour

streamchannel.

I

CHAPTER7

ECOSYSTEMSmaginelookingoutoveravastexpanseoftallgrass,gentlywavinginthewind.Itrippleswithdifferentcolors—browns,greens,yellows,andeven

reds. Then imagine walking through grass with stems higher than yourhead.Ifyouwereanearlysettlerinthiscountryheadingwest,thisiswhatyouwouldhaveencounteredasyouenteredtheprairie.

Fromafar,theprairielookslikeasimple,flat,greenarea.Butupclose,it’scleartheprairieisanamazingecosystem.Anecosystemisalltheplantsandanimalsthatliveinaplace.It’salsothephysicalenvironmentitself—thesoil,air,water,andeventhesunlight.

Everythinginanecosysteminteractswitheachother.Theplantsneedthesoilandsunlightofacertainplace,theanimalseattheplants,andtheplants

dependontheanimals.

PRAIRIE:ASEAOFGRASSPrairiesaregrasslandsthatextendformanymiles.WhenEuropeansettlersfirstsawtheprairietheycalleditaseaofgrass.Hundredsofdifferenttypesofgrass

cangrowingrasslands,alongwithmanytypesoffloweringplants,calledforbs.Thereareveryfewtreesorshrubs.

Grasslandsoftengrowinthemiddleofcontinents.Theseareasdon’treceiveenoughraintogrowaforest,butgettoomuchraintobeadesert.Prairiesarehotinthesummerandcoldinthewinter.Theyareoftenwindy.IntheUnitedStates,the original prairie stretched throughout all of the Great Plains. Most of thatprairiehasbeenconvertedtofarmlandbecausethesoilisveryfertile,buttherearepatchesofprairiestilllefthereandthere.

OriginalExtentofPrairieLand

WORDSTOKNOWfertile:landthatisgoodforgrowingplants.

TherearethreetypesofprairieintheUnitedStates.

Tallgrassprairieisfoundintheeasternportionoftheprairie,whereitreceives25to39inchesofrainperyear(63to74centimeters).Thegrassgrowstall—upto6feettall,andoccasionallyeven10feettall(2-3 meters)! Some of the most common tall grasses are Indian grass, big bluestem, little bluestem, and

switchgrass.

Short grassprairie is in thewestern area of the prairie, a 200-mile swath (322kilometers) runningalong theeastern foothillsof theRockyMountains.Thisarea receives less than10 inchesof rainfallperyear(25centimeters).Thegrassesheregrowuptoabout12inchestall(30centimeters)andincludebluegramaandbuffalograss.

Mixed-grass prairie is the area between the tall grass and short grass sections. It receives 14 to 23inchesofrainperyear(35to59centimeters).Amixtureofshortandtallgrassesgrowhere.

DIDYOUKNOWGrasslandsareknownbymanydifferentnames:PrairiesinNorthAmerica,pampasinSouthAmerica, steppes inEurasia, veld inSouthAfrica, andbushordowns inAustralia.Savannasaregrasslands that receivesomewhatmorerainandhave treesscatteredthroughout.

Prairies have numerous grazing animals, burrowing animals, birds, and lots and lots of insects.Predatorscan includewolves,badgers,hawks,owls,andcoyotes.Whataresomeplantsandanimals thatmakeprairiesunique?

GRASSGrasseshavethin,hollowstemsandstraight,narrowleaves.Theflowersarefeatheryatthetopofthestem,withoutpetals.Grassesgrowfrom theirbase.Sowhenanimalseat thegrass, itgrowsback.Grassescanreproducebyseedsaswellasbysendingoutlongundergroundstems.

Prairiegrassesaren’tlikeyourgrassathome,whichisprobablyjustonetypeofgrass.Theprairiehasmany types of grasses all growing together. They have interesting names like devil’s darning needle,squirreltail,puffsheathdropseed,andweepinglovegrass.

Prairiegrasseshavedeeproots—asdeepas6feet(2meters).Infact,upto75percentoftheplantmassinprairies isbelowground.This allows them to reachwater evenwhen there’s little rain. It alsoallowsthemtoeasilyregrowafter fires.Treesandshrubsarekilled infiresand takemuchlonger toreseedandgrow.

Itmightseemtheoppositeofwhatyou’dexpect,butprairiegrassesactuallyneedfirestocompeteagainstothertypesofplants

andsurvive.

Sod is a layerofdeadgrass and the rootsof theplants, all tangledup together.Early settlerson theprairiebuilthousesoutofsodbecausetherewerenotreesaroundforwood.Thewallscouldbe2feetthick(½meter)!Sodhouseskeptpeoplewarm,but itwashardtokeepout insects.Afteragoodrainstormtheroofcoulddripfordays.

WORDSTOKNOWgraze:toeatgrass.

regurgitate:tobringfoodupfromthestomachtothemouth.

DIDYOUKNOW?Grasscan’tbeeatenbymostanimalsbecauseitishardtodigest.Grazinganimals,suchasbisonandelk,havespecialstomachs tohelp themslowlydigest thegrass.Theyregurgitate the partially digestedgrass, called cud.They chew the cud, andswallowitagain.

FORBSForbsarefloweringplants.Someoftheforbsyoumightfindinprairiesarepurpleconeflower,leadplant,compassplant,andrattlesnakeplant.Manyanimalsdependonparticulartypesofforbs.Forexample,themonarchbutterflyneedsthemilkweedplanttolayitseggs,andtheregalfritillarybutterflyfeedsonviolets.

PRAIRIEDOGSPrairiedogsaren’tdogsatall.Theyareatypeofgroundsquirrelwithaheadandbodyaboutafootlongandatailafewincheslong(30centimetersand10centimeters).You’llseethemsittingupontheirhindlegswiththeirfrontpawsfoldedontheirstomachs.Likeotherrodents,theirteethkeepgrowing.

DIDYOUKNOW?Pocketgophers,whicharerelatedtoprairiedogs,canburrowupto300feetinonenight (91meters).Their lipsclosebehind their teeth so theydon’tgetdirt in theirmouths.

Whydon’tyouseeprairiedogswithgiantteeth?Theywearthemdownbygnawingandchewing.

Prairiedogsaresocialanimals.Groupsofprairiedogsbuildhugeundergroundburrows.Acollectionofburrowsiscalledatown.Theygreetmembersintheirgroupbyatouchingofnosesthatlookslikekissing!Buttheychaseawayprairiedogsfromothertowns.

Prairie dog towns can covermany acres and go as deep as 15 feet (4½meters)! There arewindingtunnels connecting various rooms, with “bathrooms” for their droppings, grass-lined “bedrooms” wheretheysleep,and“kitchens”wheretheystorefood.Theopeningtoaburrowismoundedupsowatercan’tenterduringfloods.There’susuallyaprairiedogsittingbythemoundasalookoutforpredators.Ifhesees

apredator,hecallsout“Yip!Yip!Yip!”anddoesabackfliptowarnotherstodiveunderground.

Prairiedogtownshaveoftenbeendestroyedbecauseprairiedogsdigupcrops.But theyalsomixupthesoil and their tunnels provide homes for other animals such as burrowing owls. Prairie dogs are animportant source of food for black-footed ferrets, hawks, and coyotes. Many people are now trying torestoreareasforprairiedogstoburrow.

DIDYOUKNOW?Thelargestprairiedogtowneverfoundcontainedabout400millionanimals.ItwasinTexasandwasabout100mileswideand250mileslong(161by402kilometers).That’slargerthan10states!

LOCUSTSYoucanfindlotsofinsectsontheprairie,munchingonitsdeliciousgrass.Oneofthemostcommonisthegrasshopper,whichcan jump20 times the lengthof itsbody. Ifyoucould jump likeagrasshopper,youwouldbeabletojumpnearly100feet(30meters)!

WORDSTOKNOWswarm:alargenumberofinsectsflyingtogether.

locusts:anothernameforgrasshopperswhentheyswarm.

hide:theskinofananimal.

drought:alongperiodoftimewithoutrain.

extinct: when a group of plants or animals dies out and there are nomore left in theworld.

Grasshoppersbunchtogetherinhugenumberswhenthereisn’trainforalongtime.Whentheyswarm,they’recalledlocusts.Aswarmcanriseashighasamile(1½kilometers)!Thenthelocustsswoopdownanddevouranyplantsaround.Therecanbebillionsoflocustsinaswarmanditcanlooklikeablackcloud.In1870therewasaswarminNebraskathatwasestimatedtocontain124billionlocusts.Itwas100mileslongand1milehigh(161kilometerslongand1½kilometershigh).Theswarmtooksixhourstopass.

BISONBison,sometimescalledAmericanbuffalo,areamazing,massivecreatures.Theyareabout6feethighattheshoulder(12meters),andweighasmuchasasmallcar!Theyhaveahuge,woollyheadandhump,andlarge, curved horns. Their bellowing call sounds like a cross between a lion’s roar and thunder. Bisonusuallyruninherdsof50to200.

Thereusedtobeasmanyas75millionbisonroamingtheprairies.NativeAmericanshadalwayshuntedbisonforfoodandtheirhides.Bythemid-1800s,EuropeansandNativeAmericanshuntedthebisonusinghorsesandfirearms,greatlyincreasingthenumberofbisonkilledeachyear.Evenmorebisondiedbecauseofdrought.Suchhugenumbersofbisondiedinthe1800sthattheynearlybecameextinct.

BisonBecauseofprotectionsputinplacetherearenowabout30,000wildbisonandabout500,000morethatareraisedfortheirmeatandhides.YoumightencounterwildbisonatYellowstoneNationalParkin

WyomingandWindCaveNationalParkinSouthDakota.

DIDYOUKNOW?InYellowstoneNationalPark,morepeopleareinjuredbybisonthanbybears.Bisonwill sometimes attack humans if they are provoked. Even though they look slow,theycanrunupto35milesperhour(56kilometers)!

WHEREHAYEALLTHEPRAIRIESGONE?

Thetallgrassprairieusedtocoverahugearea,fromNorthDakotatoOhioandMinnesotatoTexas.Elk,deer,bison,andpronghornthrived,withwolves,grizzlybears,andcoyoteshuntingthem.Today,mostofthatprairieisgone.Morethan96percenthasbeenturnedintofarmland.What’sleftisjustsmallpatchesinplaceswhereit’shardtofarm.Buttherearen’tanylargeareasofprairiethatsupportthevarietyofwildlifethatusedtolivethere.There are just a few placeswhere the prairie has been left intact or where people aretryingtorebuildit.

Flint Hills National Wildlife Refuge in Kansas has 18,500acresofprairie.DucksandgeeseusetheRefugeduringtheirspringandfallmigrations.

TheNealSmithNationalWildlifeRefugesouthwestofPrairieCity, Iowa,was purchased in 1989when itwas just a hugeareaofcornfields.Scientistsareusingseedsandfiretorestore4,000acresofprairie.Theyhavehadtofindtherightvarietyof seeds for the restored prairie. First they intentionally setfires to clear space for prairie grasses to grow.Their effortshave successfully restoreda thrivingprairie.One scientist inthe Refuge found 30 different kinds of insects in differentstagesoflifeononesingleplant!TheregalfritillarybutterflyisnowlivingintheNealSmithNationalWildlifeRefuge.Theregal fritillary is a large, orange, butterfly that hadn’t beenseeninthatpartofIowaformorethan100years.

Tallgrass Prairie Preserve in Oklahoma has 39,000 acres ofpreservedtallgrassprairie,thelargestpreservedtractofnativetallgrass prairie in theworld. There are over 700 species ofplants, 300 bird species, and 80 mammal species on thepreserve.About2,500bisonroammuchofthearea.

PRONGHORNPronghornaregrazinganimalsrelatedtoantelope.Theyarealittleover3feettallattheshoulder(1meter)andhave twobranchedhorns.They are special because they can sprint as fast as53milesperhour (85kilometersanhour),which isalmostasfastasacaron thehighway.Pronghornare thefastestanimal inNorthAmericaandoneofthefastestintheworld.Theyhavelonglegsandanextralargeheartthathelpsthempumpoxygenwhentheyrun.

Pronghorn

DIRT:YOURLIFEDEPENDSONITStepontosomegrass.Beneaththegrassisdirt,whichscientistscallsoil.Withoutsoil,wewouldn’thaveallofthefruitsandvegetableweliketoeat,oranyoftheanimalsthateatthoseplants.Soilonprairiesisdeep,dark,andfertile,withlotsoforganicmaterial,whichmeansitisgoodforfeedingplants.Prairiesoilhasformed over thousands of years. It is so good that people have taken over nearly all of the areas oncecoveredbyprairiesforfarms.AndthefarmsontheGreatPlainsaresomeofthemostproductivefarmsintheworld.

WORDSTOKNOWsoil:thetoplayeroftheearth,includingtinyrockparticlesmixedwithorganicmaterial.

organicmaterial:decomposedplantandanimalmaterial.

Plantssuchaswheatandcorndon’thavedeeproots.Thismeans theydon’thold thesoil inplaceaswellasprairiegrasses.Inthe1930s,duringseveralyearsofdrought,thesoildriedout.Windpickeduptheloosesoilandblewitforhundredsofmilesinhugeclouds.Soilsometimescoveredhalfahouseovernightandformeddriftsupto25feethigh(7½meters)!In1936,theSoilConservationServicewasformedtohelppeopledevelopbetterwaysoffarmingtopreventsoilerosion.

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MAKEYOUROWNHOOPCOUNTS

SUPPLIEShulahoop

notebook

pencil

magnifyingglass

Findafieldormeadow.Ifyoucan,pickaplacethathasn’tbeenusedtogrowcropsinawhile.Theplantsshouldbegrowingnaturally.

Tossthehulahoopontotheground.Nowcountthenumberofplantspeciesthatareinsidethehulahoop.Inyournotebook,writeabriefdescriptionofeachtypeofplant,includinggrasses,shrubs,andfloweringplants.

Dothesamethingintwoorthreeotherplacesinthefield.

4Nowrecord thenumberof species insideyourhulahoop ina fewplacesonyour lawn,oron thegrassinapark.Whichplacehasmoreplantspecies?

WHAT’SHAPPENING?Grasslawnsaregreatplacesforrunningandplaying,butthey’renotthebestplacesforplantdiversity.Theyarewhatiscalledamonoculture,wherejustonetypeofplantisgrown.Prairieshavemany,manytypesofplantstohelpthemresistdamagefromdiseasesandinsects.Withavarietyofplants,they

alsoformhabitatsformanydifferenttypesofanimals.

WORDSTOKNOWdiversity:whenmanydifferentpeopleorthingsexistwithinagrouporplace.

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MAKEYOUROWNGRPSSY“TREE”

SUPPLIESlidofashoebox

waxpaper

pottingsoil

grassseed

water

spraybottle

oneormorepinecones

Linetheshoeboxlidwithwaxpaper.Fillthelidwiththesoilandsprinklegrassseedontop.Lightlyspraythemixturewithwaterusingthespraybottle.Makesurethespraybottleyouuseiseitherneworhasonlyheldwater.

Holdthepineconesunderrunningwaterforaminutetogetthemcompletelywet.

Setthepineconesuprightinthesoilintheshoeboxlid.Gentlypresssomesoilontothetopsofthepineconesandthescalesofeachpinecone.Pressthegrassseedintothesoil.Sprayallofthesoiluntilit’smoist.

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Placetheshoeboxlidonasunnywindowsill.Overthenextfewdays,lightlyspraythesoilinthelidandon thepinecones tokeepeverythingmoist.You’llneed tospray thesoilseveral timesaday.Usescissorstogiveyourgrassahaircutifitneedsit.

Ifyou’dlike,youcantrydifferenttypesofgrassseedondifferentpinecones.Noticethedifferencesinwhattheylooklikeandhowlongtheytaketogerminate.

WORDSTOKNOWgerminate:tostartgrowingfromseed.

WHAT’SHAPPENING?Grassseedgerminatesfairlyeasily.Allitneedsismoisture,warmth,and

somesoil.Oncetheystart,thetinygrassplantsneedlighttobeabletomaketheirownfoodandgrow.Ifyourgrassseeddidn’tgerminate,themostlikely

reasonisthatitdriedout.Tryagainandkeepthesoilmoist.

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GROWYOUROWNSUNFLOWERS

SUPPLIES

potwithadrainageholeinthebottom

pottingsoil

water

packageofsunflowerseeds

Fillthepotwiththepottingsoil.Addwatertothesoiluntilitisdamp,butnotsoaked.

Plant2or3sunflowerseedsinthepot.Covertheseedswithasmuchsoilasisindicatedontheseedpackage.Gentlywatertheseedsandplacethepotonasunnywindowsill.

When the sunflower plants are a few inches high (about 8 centimeters), notice which one is thebiggestandhealthiest.Pulloutalltheothers,leavingthebiggestonetocontinuegrowing.

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Oncethedangeroffrostisgonewhereyoulive,youcantransplantyoursunfloweroutside.Chooseasunnyplacethatisn’twindy.

Digaholethatisbiggerthanyourpot.Carefullyliftyoursoilandplantoutofthepotandplaceitinthehole.Wateryourplantandplaceawoodenstakebehindit.Whentheplantgrowslarger,tietheplanttothestakesoitwon’tdroopover.

Youcanalsoplantsunflowerseedsdirectlyintheground.You’llhavetowaitabitlongertostartsoyoucanplanttheseedsafterthedangeroffrostisgone.Plantanentirerowofsunflowersalongafence.Orcreateasquareshapetoformasunflowerhouse.

WHAT’SHAPPENING?Sunflowersareoneofmanytypesofflowersthatarenativetotheprairie.ThesunfloweristhestateflowerofKansasandasymboloftheprairie.Thisisa

funprojecttostartinearlyspring.

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CHAPTER8

THEGREATLAKESfyoustandontheshoresofLakeSuperior,youmightthinkthatyou’restandingon theshoresofanocean.Thewaterspreadsoutas farasyou

can see. The waves can be huge. And the beaches are like those on theAtlanticorPacificOceans.

Buttakeaswiminthewaterandyou’llsoonrealizethere’sonebigdifference:the water of Lake Superior—and all of the Great Lakes—doesn’t taste salty.Thesearefreshwaterlakes.TheGreatLakessupporthumancommunitieslargeandsmall,andahugevarietyofplantsandanimals.

TheGreatLakesaremadeupoffivelakes.LakeSuperioristhelargestlake,and the highest in elevation. Water flows from Lake Superior down the St.Marys River for 60 miles (97 kilometers) to Lake Huron. Lake Michigan isconnectedtoLakeHuronbythedeepStraitsofMackinac.Fromawaterpointofview,MichiganandHuronareconsideredtobeonelake,becausethelevelsofthelakesriseandfalltogether.

WaterthenflowsfromLakeHurondowntheSt.ClairRiver, throughLakeSt.Clair,anddowntheDetroitRivertoreachLakeErie.FromLakeErie,watertravelsdowntheNiagaraRiver,over theNiagaraFalls,andintoLakeOntario.Theman-madeWellandCanalgoesaroundNiagaraFallstoallowshipstopass.Finally, water flows from Lake Ontario into the St. Lawrence River and theAtlanticOcean.

DIDYOUKNOW?Even though each lake has its own separate basin, all of thelakes are connected. They’re also connected to the AtlanticOcean.

GREATLAKESQUICKFACTSTheGreatLakes hold 21percent of the freshwater onEarthandarethelargestgroupoffreshwaterlakesbysurfaceareain

theworld.Thatmeansthatforevery5gallonsoffreshwaterintheworld(19liters),1gallonofitisintheGreatLakes(33/4liters).The Great Lakes hold enough water to cover the entirecontinentalUnitedStatesin9½feetofwater(3meters)!The Great Lakes border seven states: Michigan,Wisconsin,Minnesota,Illinois,Ohio,Pennsylvania,andNewYork.LakeSuperioris thelargest,deepest,coldest,andcleanestofthe lakes. It is 1,332 feet deep (406meters), and holds one-tenth of the world’s freshwater. By surface area, it is thelargestlakeintheworld.Theaveragewatertemperatureis40degreesFahrenheit(4degreesCelsius).Brrrr!LakeErieisonly210feetdeepatitsdeepest(64meters),anditfreezesoverquicklyinthewinter.LakeMichigan is theonly lake that iscompletelywithin theUnitedStatesborders.Theother fourborderboth theUnitedStatesandCanada.Thereareover35,000islandsinalloftheGreatLakes.TheGreatLakes takeup asmuch space asNewYork,NewJersey, Connecticut, Rhode Island,Massachusetts, Vermont,andNewHampshirecombined.Lake Michigan splits the state of Michigan into two partscalledtheUpperPeninsulaandtheLowerPeninsula.

HOWTHEYWEREFORMEDTheGreatLakes arebotholdandyoung.Their roots aredeep—theygot theirstart over one billion years ago. That’s when the North American continentbeganriftingapart. If ithadkeptgoing,anewoceanwouldhaveformed.Therifting stopped, but it left an arch-shaped basin. The top of the arch iswhereLakeSuperiorisnow,anditsnorthshoreisthenorthernarcoftherift.Anotherrift started 570million years ago that formed the basins for the St. Lawrence

River andLakesOntario andErie.These two rifts shaped the land into broadbasins,butthelandwasstilldryatthispoint.

About10,000yearsago,duringthelasticeage,theregionwascoveredbyglaciersmorethanamilethick(1.6kilometers).

The glaciers pressed down on the land and carved out depressions andvalleys.When the earth warmed and the glaciers melted, the water filled thevalleystoformtheGreatLakes.

WORDSTOKNOWmollusk:ananimalwithasoftbodyprotectedbyashell,suchasaclamorsnail.

sanddune:ahillofsand.

SHORELINEBeaches,marshes,bogs,sanddunes,androckyshoresareallfoundattheGreatLakes.Theshorelinesarediversebecauseofthevarietyofunderlyingrocks,thechangingclimate,andthecarvingbyglaciers.

Sandy beaches are the most common type of shoreline. You can findmigratory shorebirds, insects, andmollusks here.And of course humans!Thesanddunes of theGreatLakes are the largest freshwater coastal dunes in theworld.Themost famous are theSleepingBearDunesonLakeMichigan.Thedunestherecanreachashighas400feet(122meters)alongthebeaches.

WORDSTOKNOWwetland:anarealocatedaroundlakesandriversthatcontainsalotofsoilmoisture.

fishery:aplaceforcatchingfish.

overfishing:whensomanyfisharecaughteachyearthattherearenotenoughleft.

parasite:alivingthingthatfeedsoffanotherlivingthing.

Wetlands, such asmarshes, swamps, and bogs,may not sound like a funplacetogo.Butwetlandssupportanincrediblevarietyoflife.Theyarethemostproductiveecosystemsintheworld.Anyareathatisnotdryland,butisn’topenwatereither, isawetland.Migratorybirds lovewetlands,where theycanfeastoninsectsandmollusks.

POLLUTIONInJune1969,theCuyahogaRiver,whichflowsintoLakeErie,caughtfireasitflowedthroughCleveland,Ohio.Peoplewerehorrified.Howcouldarivercatchfire?Itwassopollutedwithoilandchemicalsfloatingontop,creatingabrown,oilysheen,thatitburned.

Formanyyears,peoplehaddumpedchemicals,rawsewage,andevendeadanimalsintheCuyahogaandotherriversfeedingtheGreatLakes.

FISHINGTheGreatLakesareoneofthelargestfisheriesintheworld.Someof the most common species caught include whitefish, trout,salmon, walleye, and perch. Lake Erie is the most productivefishery of theGreat Lakes. The largest catches recordedwere in1888 and 1899 at 147 million pounds of fish (67 millionkilograms)!

Pollutionandoverfishinghavereducedtheamountoffishcaught

since then. But fish numbers are increasing as people work toprotectthelakes.Eachyear,theGreatLakesfisheryisworthmorethanfourbilliondollars.

Peoplethoughtthewaterwouldtakecareofthewaste.Theproblemsbeganinthe1700swithoverfishingandthedammingupofrivers.Later,fertilizerusedby farmers and homeowners was washed into the lakes. Algae, which lovefertilizer, grew rapidly. But algae used up all of the oxygen in the lakes, andtherewasn’tenoughforfish.

Bythe1960s,LakeEriewascoveredinalgaeslimeanddeclared“Dead.”

TheburningCuyahogaRiverwasawake-upcall,andpeoplestartedcleaningup the rivers and lakes. New laws, including the Clean Water Act andagreements between theUnited States andCanada, have helped to restore theGreatLakes.There’sstillmoreworktodo,butthelakesarenolongerdead.ThefisharereturningtotheCuyahogaRiver.

VAMPIRES!Inthe1930s,akindof“vampire”enteredtheGreatLakes.Thisvampiredoesn’twearablackcape,anddoesn’thavefangs,but itdoessuckblood.Fishblood,that is. It’s called a sea lamprey.Sea lampreyshave a snakelikebody and areparasitestomanyfish.Theydon’thavejaws,buttheyattachontofishwiththeirmouths and suck their blood. By the 1950s, lampreys had almost wiped outmanyfish.LakesMichiganandHuronlostalmosttheirentiretroutpopulations.

WORDSTOKNOWinvasivespecies:aspecies that isnotnative toanecosystemandthatisharmfultotheecosysteminsomeway.

nativespecies:aspeciesthatisnativetoanecosystem.

ballast: fresh or salt water carried by ships to help balance theship.

suspensionbridge:abridgewhoseroadissuspendedfromtwoormorecablesthatpassovertowers.

Invasive species are plants or animals that come into an area from elsewhereandhaveanegativeimpactontheecosystem.Lampreysareamongtheworstofinvasivespecies,butthey’renottheonlyones.Manyinvasivespeciescompete

forspaceorfood,crowdingoutnativespecies.

Therehavebeenover160speciesofplantsandanimalsintroducedintotheGreatLakes in the last centuryor so.Most came in as “passengers”on ships.Shipscarryballasttohelpbalancetheship.Ballastispickedupanddischargedinports,andplantsandanimalscanbeaccidentallytakenoninoneplace,thenletgoinanother.

Otherinvasivespeciesinclude:

Purpleloosestrife,whichhasdisplacednativeplantsalongthelakeshores.Goby,afishthatlivesonthelakebottomandeatstremendousamountsoffood.Zebramussels,whicharefingernail-sizedmusselswithastripedpatternontheirshells.TheywerefirstdiscoveredintheGreatLakesinthe1960sandin10yearshadspreadthroughoutallofthelakes.Thesemusselshavenowbeen found all the way down theMississippi River. Zebra mussels clogpipesandencrustanyhardsurface,includingshipbottomsandevenothermussels.

DIDYOUKNOW?TheMackinacBridge(called“BigMac”) is theworld’s third-longest suspension bridge. It’s about 5 miles long (8kilometers) and crosses the Straits ofMackinac where LakesMichiganandHuronmeet.

LAKESANDISLANDSManitoulinIslandonLakeHuronisthelargestislandinanyinlandbody of water in the world. Isle Royale in Lake Superior is thesecond-largest island.Andbothoftheseislandshavelakeswithinthem.WithinManitoulin Island,LakeManitou is the largest lake

locatedonafreshwaterislandintheworld.Youcancallita“lakein a lake.”And guesswhat?LakeManitou has small islands. Sothoseislandsareislandsinalakeonanislandinalake!

ApotentialinvasivespeciesthathaspeopleworriedistheAsianCarp.Thisfishcanweighupto100pounds(45kilograms),grow4feetlong(1¼meters),and live for 25years.AsianCarp are established in theMississippiRiver andhavebeenslowlymigratingnorth.

Becausetheyaresobig,thesecarpconsumemuchofthefoodresourcesofotherfish.

The Great Lakes are connected to the Mississippi River by a man-madecanal,namedtheChicagoSanitaryandShipCanal.ItallowsgoodsandpeopletomovebetweentheGreatLakesandtheMississippiRiver.Butthatconnectionalsoallowsunwantedspeciestomigratebetweenthelakesandtheriveraswell.

For now, a series of three electric barriers keep the fish out of the GreatLakes. But many people are concerned that the fish could get through those

barriers.Somepeople,especiallythoseinthefishingindustry,wanttoclosetheChicago Sanitary and Ship Canal. This would keep the carp out. But others,especiallyintheshippingindustry,favorkeepingthecanalopen.

WORDSTOKNOWcargo:goodscarriedbyship.

rawmaterial:aresourceusedinfactoriestomakethings.

SHIPPINGTheGreatLakes are an important place for shippinggoods around the centralUnitedStates.Thereare63commercialportsonthelakes,andover150milliontonsofcargo isshipped inayear (136millionmetric tons).MostshippingontheGreatLakesisinrawmaterialssuchasironore,limestone,grain,andcoal.

LAKESSLANG

The Great Lakes have some of their own slang terms: ThirdCoast:theshoresoftheGreatLakes,especiallyLakeMichigan.

Boat:termforanyship,nomatterhowbigitis.

Laker:aboatthattradesonthelakes.

Salties:ocean-goingboatstemporarilyintheGreatLakes.

WORDSTOKNOWicebreaker: a ship built for breaking a passage through frozenwater.

Freighters thatcarrytheserawmaterialscantravelbetweenallof thelakesand out to the ocean. The automotive industry, centered in Detroit on LakeMichigan,islocatedintheGreatLakesregionbecausethelakesmakeiteasytotransportmaterials.

Thelakesfreezeoverinmanyareasinwinter.Shipscalledicebreakerskeeptheshippinglanesopeninwinter.Icebreakersarespeciallydesignedtobeabletobreak through ice-coveredwater.Theyhavepowerful engines thatpush thebow,orfrontoftheship,upontotheice.Thentheweightoftheshipbreakstheice.Anicebreakerhasaspecialshapethatpushesthebrokeniceoutoftheway.Theyarealsoespeciallystrongtowithstandthebatteringtheytake.

DIDYOUKNOW?TheWitchTree(alsocalledLittleSpiritCedarTree)inGrandPortage,Minnesota, is a tree thathasclung tobouldersat theedgeofLakeSuperior for at least 300years. It’s gnarled andstunted. Youwould be too if you were living on a rock andbatteredbystormwaves!ThistreeisconsideredsacredbytheOjibwaIndians.

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MAKEYOUROWNTEMPERATUREGRADIENTS

SUPPLIES2smallclearbottleswithflatsides,suchassaladdressingbottles,withcapslarge clear bucket or container that is wider than thebottlesaretallbowlwithaflatbottomthatwillfitinsidethebuckettapwatericewater2colorsoffoodcoloringhotwater

Rinseoutallofthecontainersandremoveanylabels.Fillthelargebucketwithtapwater.

Place the bowl inside the bucket and turn it upside down so that no airremainsinthebowl.Setitonthebottomofthebucket.

Fillonebottlewith icewater (butdon’tput ice in thebottle).Adda fewdropsofonecoloroffoodcoloring.Filltheotherbottlewithhottapwater

andaddafewdropsoftheothercoloroffoodcoloring.Placethebottlecapsbackoneachbottleandgentlytightenthecaps.

4Placeeachbottleonitssideontopofthebowlinsidethebucket.Removebothbottlecaps.Watchwhathappenstotheicewater!Whathappenstothe

hotwater?

WHAT’SHAPPENING?Thewaterseparatesintolayersbecauseofdifferencesinthedensityofthewater.Hotterwaterislessdenseandcolderwaterismoredense.Thedenser,colderwatersinkstothebottom,andthelessdense,warmerwaterrisestothe

top.

ThesamethinghappensintheGreatLakes.Therearelayersoftemperature,

withwarmertemperaturesnearthesurface.Thewaterbecomescolderwithdepth.Insomeplaces,thewaterchangesasmuchas26degreesFahrenheitin

just10feet(3meters)!Thewateratthebottomofthelakesisclosetofreezing.

Upwellingiswhencolderwaterrisestothesurfacebecauseofwindsmovingthesurfacewater.Thesecolderwatersoftenbringnutrientsupandcreate

abundantfisheries.

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MAKEYOUROWNSANDDUNES

SUPPLIEScardboard box, at least 2 feet long and wide (61centimeters)scissors50-poundbagofplaysand,available fromthehardwarestoreblowdryerafewrocksofvarioussizes,uptothesizeofabaseballwateroutdoorspace

Makeacardboardtraytoholdthesand:Selectthesideoftheboxthathasthelongestlengthandwidth.Setthatsideonthefloor.Cutthecardboard

boxsothatitisopenonthetopandhasa6-inch-highwall(15centimeters).

Scoopsandintothecardboardtraysothesandisafewinchesdeep(about8centimeters).

Using theblowdryer,blowsandso that itpilesup intoduneshapes.DOTHISOUTDOORS!

4Tryplacingdifferentsizerocksinthebox,andblowtowardstherocks.Canyoumake the dunes different shapes by changingwind directions?What

happenswhenyou sprinklewateron the sand?Tryblowing the sand intoasmalldune,thensprinklesomewaterdirectlyontheduneandblowdrysandontopofthat.Isiteasierorhardertomaketallerdunes?Whathappensifallofthesandiswet?

WHAT’SHAPPENING?TheGreatLakesareknownfortheirsandybeachesandsanddunes.Howdosanddunesform?Youneedtwothingsinadditiontosand:windthat’sstrong,steady,andthatsometimesreversesdirections,andconditionsthatkeepthesandloose.Varyingthesecomponentsmakesdifferent-shapeddunes.In

addition,vegetationsortsandtrapsthesand.SandduneshaveformedalongthecoastsofalloftheGreatLakes.Thebest-knownofthesedunesarealongthecoastsofLakeMichigan,whichcontainsthelargestconcentrationoffresh

waterdunesintheworld!

ThedunesalongLakeMichiganformedthousandsofyearsagowhenglacierscoveredtheland.Theglacierstransportedlargeamountsofsandtothearea.Whentheglaciersfinallyretreatedabout3,000yearsago,theydumpedout

thesandastheicemelted.Thenthewindandwaterformedthesandintodunes.Thatprocesscontinuestoday,aswavescutawaythebasesofbluffs,

andwindblowsthesandupwardtobedepositedontopofthedunes.Vegetationlikegrassesandshrubstrapsthesandandholdsitinplace.

TheGreatLakeshaveagreatvarietyofsanddunetypes.Parabolicdunesarecrescent-shapeddunesthatareanchoredbyplants.Perchedduneshaveformedontopofglacialmoraines.Lineardunesarelongdunesthatformparalleltotheshoreline.Andtransversedunesformperpendiculartothe

wind.

GLOSSARYacidic:fromacids,whicharechemicalcompoundsthattastesour.

adapt:changesaplantoranimalmakestosurvive.

alpineglacier:aglacierthatformsinthemountains.

altitude:theheightabovesealevel.Alsocalledelevation.

AncestralRockies: amountainchain that formedover300millionyearsago.Thesemountainswereeroded,buttherocksformedthencanbeseenintoday’sRockyMountains.

asthenosphere: the semi-molten middle layer of the earth that includes thelowermantle.Muchoftheasthenosphereflowsslowly,likeSillyPutty.

atmosphere:theairsurroundingtheearth.

atom: the smallest particle of matter that cannot be broken down withoutchanging the particle’s properties. Everything on Earth is made of variouscombinationsofatoms.

ballast:freshorsaltwatercarriedbyshipstohelpbalancetheship.

barge:aboatwithaflatbottomusedtocarryloadsoncanalsandrivers.

basin:alowareashapedlikeabowl.

birdofprey:abirdthathuntsanimalsforfood.

blizzard: a severe snow stormwith highwinds, low temperatures, and heavysnow.

brittle:describesasolidthatbreakswhenputunderpressure.Abladeofgrass

willbend,butadrytwigisbrittleandwillbreak.

caldera: a large volcanic crater, usually formed by a large eruption thatcollapsedthemouthofthevolcano.

canal:aman-madewaterway.

carbon dioxide: a gas formed by the rotting of plants and animals andwhenanimalsbreatheout.

carbonicacid:aweakacidformedwhencarbondioxidedissolvesinwater.

cargo:goodscarriedbyship.

cave:anaturalundergroundopeningconnectedtothesurface,largeenoughforapersontoenter.

cavern:averylargecaveorsystemofconnectedcaves.

cirque:abasinattheheadofaglacialvalley,whichoftencontainsalake.

climate:theaverageweatherofanareaoveralongperiodoftime.

condense:tochangefromagastoaliquid.

confluence:thepointwheretwoormorestreamsflowtogether.

continental:relatingtotheearth’slargelandmasses.

continental climate: the climate found in the middle of a continent. It ischaracterizedbylargevariationsintemperatureandfourseasons.

continental platform: the central, stable part of the craton that is covered bysedimentsandsedimentaryrocks.

continental shield: thepartof thecratonwhere theancient rocksareexposedandarenotcoveredbysediments.

convergentboundary:wheretwoplatescometogether.

core: thecenteroftheearth,composedofthemetalsironandnickel.Thecorehastwoparts—asolidinnercore,andaliquidoutercore.

craton:thestable,centralpartofacontinent.

crust:thethick,outerlayeroftheearth.

current:aconstantlymovingmassofliquid.

dam:alarge,strongwallbuiltacrossarivertoholdbackandcontrolthewater.

dense:tightlypacked.

divergent boundary: where two plates are moving in opposite directions,sometimes called a rift zone. New crust forms at rift zones from the magmapushingthroughthecrust.

diversity:whenmanydifferentpeopleorthingsexistwithinagrouporplace.

drought:alongperiodoftimewithoutrain.

earthquake:asuddenmovementintheouterlayeroftheearth.Itreleasesstressbuiltupfromthemotionoftheearth’splates.

ecosystem: a community of plants and animals living in the same area andrelyingoneachothertosurvive.

element:asubstancethatismadeupofatomsthatareallthesame.

EnhancedFujitascale:ascaleusedtomeasurethestrengthoftornadoesbased

on the destruction they cause. The scale runs from EF-0 to EF-5, with EF-5beingthestrongest.

epicenter: the point on the earth’s surface directly above the location of theearthquake.

erosion:thewearingawayandcarryingoffofmaterialsontheearth’ssurface.

erupt:toburstoutsuddenly.

extinct:whenagroupofplantsoranimalsdiesoutandtherearenomoreleftintheworld.

fault:acrackintheouterlayeroftheearth.

fertile:landthatisgoodforgrowingplants.

firn:granularsnowthathasnotyetbeencompressedintoice.

fishery:aplaceforcatchingfish.

floodplain:theflatlandnexttoariverthatfloodswhentheriveroverflows.

freshwater:waterthatisnotsalty.

fumarole:aventthatletsouthotgases.

geography: the studyof the earth and its features, especially the shapeof theland,andtheeffectofhumanactivity.

geologist:ascientistwhostudiestheearthanditsmovements.

geology:thescientificstudyofthehistoryandphysicalnatureoftheearth.

germinate:tostartgrowingfromseed.

geyser:ahotspringthatperiodicallyejectswaterandsteamintheair.

glacialperiod:aperiodoftimewithinaniceagewhenalargepartoftheearth’ssurfaceiscoveredwithice.

glacier:ahugemassoficeandsnow.

granule:asmallgrainorpellet.

grassland:alargeareaoflandcoveredwithgrass.

gravity:theforcethatpullsobjectstotheearth.

graze:toeatgrass.

habitat:thenaturalareawhereaplantoranimallives.

hail:ballsoficeandfrozensnowthatfalllikerain.

half-life:theamountoftimeittakesforonehalfofaradioactiveparentelementtodecaytoitsdaughter.

hangingvalley:asidevalleythatjoinsthemainvalleyatahigherlevel.Itformswhenasmallerglacierdoesn’terodeasdeeplyasthemainglacier.

headwater:ariver’ssource.

hide:theskinofananimal.

hotspot:anareainthemiddleofaplate,wherehotmagmarisestothesurface.

hot spring: a natural pool ofwater that is heated by hot ormolten rock.Hotspringsarefoundinareasofvolcanicactivity.

hydrosphere: the earth’s water, including oceans, rivers, lakes, glaciers, and

watervaporintheair.

Ice Age: a period of timewhen large ice sheets cover large areas of land. ItparticularlyreferstothemostrecentseriesofglaciationsduringthePleistocene.Aniceagecanincludeshorterperiodswhenglaciersretreat,aswellasperiodswhentheglaciersgrow.

icebreaker:ashipbuiltforbreakingapassagethroughfrozenwater.

igneousrock:rockthatformsfromcoolingmagma.

interglacial period: a periodwithin an ice age that is somewhatwarmer andglaciersretreat.

invasivespecies:aspeciesthatisnotnativetoanecosystemandthatisharmfultotheecosysteminsomeway.

jetstream:ahighspeedflowofairhighintheatmospherethatflowsfromwesttoeastandoftenbringsweatherwithit.

levee:awallofearthorstonebuiltalongariverbanktopreventfloodingoftheland.

limestone: a sedimentary rock that forms from the skeletons and shells of seacreatures.Limestoneerodeseasily.

lithosphere: the rigid outer layer of the earth that includes the crust and theuppermantle.

lobe: an extension of a glacier, with a shape like a tongue. The Wisconsinglaciationhadsixmajorlobes.

locusts:anothernameforgrasshopperswhentheyswarm.

magma:partiallymeltedrockbelowthesurfaceoftheearth.

mantle:themiddlelayeroftheearth.Theuppermantle,togetherwiththecrust,formsthelithosphere.

metamorphicrock:rockthathasbeentransformedbyheatorpressureorbothintonewrock,whilestayingsolid.

meteorologist:ascientistwhostudiesandforecastsclimateandweather.

migrate:tomovefromoneplacetoanothereachyear.

migratorybird:abirdthatmigrates.

mollusk:ananimalwithasoftbodyprotectedbyashell,suchasaclamorsnail.

molten:meltedbyheattoformaliquid.

moraine:anaccumulationofgravelandsanddepositedatthefrontofaglacier.

mudpot:aboilingareaofmud.

nativespecies:aspeciesthatisnativetoanecosystem.

oceanic:inorfromtheocean.

organicmaterial:decomposedplantandanimalmaterial.

overfishing:whensomanyfisharecaughteachyearthattherearenotenoughleft.

parasite:alivingthingthatfeedsoffanotherlivingthing.

plains:aflatexpanseofland.

plateau:alarge,raisedareathatisfairlyflat.

plates:huge,moving,interconnectedslabsoflithosphere.

platetectonics:thetheorythatdescribeshowplatesmoveacrosstheearthandinteractwitheachothertoproduceearthquakes,volcanoes,andmountains.

Pleistocene: theepoch ingeologichistory fromabout2.5millionyearsago to10,000yearsagothatexperiencedrepeatedglaciations.

port:aplacewhereshipscanloadandunload.

prairie:thewide,rollinglandcoveredingrasses,westoftheMississippiRiver.

precipitation:thefallingtoearthofrain,snow,oranyformofwater.

predator:ananimalthathuntsanotheranimalforfood.

radiometric dating: a method of determining the age of rocks. It looks at aradioactive element in rock, such as uranium, andmeasures howmuch it hasdecayed.

rawmaterial:aresourceusedinfactoriestomakethings.

regurgitate:tobringfoodupfromthestomachtothemouth.

reservoir:anareathatholdswaterbehindadam.

Richterscale:ascaleusedtomeasurethestrengthofanearthquake.

rifting:whenthelithospheresplitsapart.

rockflour:fine-grainedsedimentmadefromglaciersgrindingoverbedrock.

RockyMountains:amountainrangerunningfromNewMexicointoCanada.

sanddune:ahillofsand.

sediment:looserockparticlessuchassandorclay.

sedimentaryrock:rockformedfromthecompressionofsediments,theremainsofplantsandanimals,orfromtheevaporationofseawater.

seismicwave:awaveofenergygeneratedfromanearthquake.Thewavetravelsthroughtheearth.

seismograph:aninstrumentthatmeasurestheintensityofaseismicwave.

soil:thetoplayeroftheearth,includingtinyrockparticlesmixedwithorganicmaterial.

species:agroupofplantsoranimalsthatarerelatedandlookthesame.

speleothem:adistinctivecaveformation,suchasastalactite.

stalactite:acaveformationthatlookslikeaniciclehangingfromtheceiling.

stalagmite: a cave formation that sticks up from the floor, often under astalactite.

steamboat:aboatwithapaddlewheelthatisturnedbyasteamengine.

steamengine:anenginethatburnswoodorcoaltoheatwaterandcreatesteam.Thesteamgeneratespowertoruntheengine.

subduction:whenonetectonicplateslidesunderneathanothertectonicplate.

supercell: a severe thunderstorm with strong updrafts and downdrafts of air.Supercells often have large hail, strong winds, downpours, and sometimestornadoes.

suspensionbridge:abridgewhoseroadissuspendedfromtwoormorecables

thatpassovertowers.

swarm:alargenumberofinsectsflyingtogether.

tectonic:relatingtotheforcesthatproducemovementandchangesintheearth’scrust.

theMidwest: another name for the Great Plains in themiddle of the UnitedStates.

thermal:relatedtoheat.

tornado: a violent, twisting, funnel-shaped column of air extending from athunderstormtotheground.

transformboundary:wheretwoplatesslideagainsteachother.

tributary:astreamorriverthatflowsintoalargerriver.

U-shapedvalley:avalleythathasbeencarvedbyaglacierandhasashapeliketheletter“U,”withsteepsidesandaflatfloor.

volcano: a vent in the earth’s surface through which magma, ash, and gaseserupt.

watershed:thelandareathatdrainsintoariverorstream.

wetland: an area located around lakes and rivers that contains a lot of soilmoisture.

windshear:achange in thedirectionofwind,especiallywhenwindblowsindifferentdirectionsatdifferentheights.

zoneofablation:theareaonaglacierwheresnoworicemeltsorevaporates.

zoneofaccumulation:theareaonaglacierwheresnowaccumulates.

RESOURCESBOOKS

Anderson,Alan,GwenDiehn,andTerryKrautwurst.GeologyCrafts forKids:50NiftyProjects toExplore theMarvelsofPlanetEarth.NewYork:Sterling,1998.

Bennett,Clayton.Montant(CelebratetheStates,Second).NewYork:MarshallCavendish,2010.

Bennett,MichelleandJoyceHart.Missouri(CelebratetheStates,Second).NewYork:MarshallCavendish,2010.

Bjorkland,Ruth.Nebraska(CelebratetheStates,Second).NewYork:MarshallCavendish,2010.

Blobaum,CindyandMichaelKline.GeologyRocks!:50Hands-OnActivitiestoExploretheEarth.Vermont:WilliamsonPublishingCompany,1999.

Chambers,Catherine.LifeintheGrasslands.NewYork:Children’sPress,2005.

Collard, Sneed B. III. The Prairie Builders: Reconstructing America’s LostGrasslands.Boston:HoughtonMifflinBoston,2005.

Farndon,John.HowtheEarthWorks.NewYork:DorlingKindersleyPublishersLtd,1999.

Geore,Michael.Glaciers.Mankato,Minnesota:CreativeEducation,Inc.,1991.

Ingram, Scott. Kansas (From Sea to Shining Sea, Second). New York:Children’sPress,2009.

Jensen,NielsR.Ohio(CheckerboardGeographyLibrary:UnitedStates).Edina,Minnesota:CheckerboardBooks,2009.

Johnson, Elizabeth.Michigan (From Sea to Shining Sea, Second).NewYork:Children’sPress,2009.

Johnson, Rebecca L. AWalk in the Prairie. Minneapolis: Carolrhoda Books,2001.

Ling, Bettina. Wisconsin (From Sea to Shining Sea, Second). New York:Children’sPress,2008.

Lynch,Wayne.PrairieGrasslands.Minnetonka,Minnesota:NorthWordBooksforYoungReaders,2006.

McDaniel,Melissa.North Dakota (Celebrate the States, Second). New York:MarshallCavendish,2010.

Miller, Amy. Colorado (From Sea to Shining Sea, Second). New York:Children’sPress,2008.

Nadeau,Isaac.Glaciers.NewYork:PowerkidsPress,2006.

Ollhoff, Jim.Wyoming (The United States). Edina, Minnesota: CheckerboardBooks,2009.

Schwabacher,Martin,andPatriciaK.Kummer.Minnesota(CelebratetheStates,Second).NewYork:MarshallCavendish,2008.

Smith, Richard. Indiana (Checkerboard Geography Library: United States).EdinaMinnesota:CheckerboardBooks,2009.

Somervill, Barbara. Illinois (From Sea to Shining Sea, Second). New York:Children’sPress,2008.

Wheeler, Jill C. Iowa (United States). Edina, Minnesota: Abdo PublishingCompany,2009.

Yacowitz,Caryn.SouthDakota(FromSeatoShiningSea,Second).NewYork:Children’sPress,2009.

WEBSITESwww.maps.google.com Satellite view of the Great Plains and MountainWest.Click on theSatellite tab and scroll towherever youwant to look.Youcanzoominorout.www.nps.gov/NationalParkServicemainwebsite.Clickonlinkstofindspecificnationalparksandmonuments.http://mineralsciences.si.edu/tdpmap/ World Interactive Map ofVolcanoes, Earthquakes, Impact Craters, and Plate Tectonics, bySmithsonian,USGS,andUSNavalResearchLaboratory.http://earthquake.usgs.gov/earthquakes/ Earthquakes in all states.Clickonlinkontheleftcalled“EarthquakeLists&Maps,thenclickonlink“ByState” toviewinformationaboutaparticularstate.Thereare lotsofotherlinkswithinterestinginformation.http://earthquake.usgs.gov/learn/kids/U.S.GeologicalSurvey(U.S.G.S.)EarthquakesforKidssite.http://volcanoes.usgs.gov/yvo/activity/monitoring/WebsiteofactivevolcanicmonitoringofYellowstoneNationalPark.www.nps.gov/yell/naturescience/volcanoqa.htmYellowstoneNationalParkquestionsandanswers.www.nps.gov/iatr/index.htmIceAgeNationalScenicTrail.www.nssl.noaa.gov/primer/tornado/tor_climatology.htmlNational Oceanic and Atmospheric Administration, general informationabouttornadoes.www.usatoday.com/weather/resources/askjack/archives-weather-extremes.htmQuestionsandAnswersaboutWeatherfacts.www.americanrivers.org/about-rivers/

Rivers:factsaboutrivers,dams,riversongs,andmore.http://water.usgs.gov/WaterResourcesintheU.S.bytheUSGS.www.tallgrass.org Friends of the Prairie Learning Center, Neal SmithNationalWildlifeRefuge.www.42explore.com/prairie.htm 42eXplore - this site has coolinformation about all kindsof stuff, includingprairies (clickon theMainMenutoseeothertopics).www.nationalgeographic.com/features/98/burrow/Prairiedogs.http://coseegreatlakes.net/curriculum/ Great Lakes: Projects andinformation.www.epa.gov/glnpo/image/VisualizingtheGreatLakes:alibraryofpicturesfromtheGreatLakes.www.glerl.noaa.gov/data/ NOAA Great Lakes Environmental ResearchLaboratory.

INDEXA

activities(MakeYourOwn…)

ContinentalClimate,71

Flood,84–85

FoldedMountains,30–31

Geyser,44

Grassy“Tree,”96–97

HoopCounts,95

Kettles,57

Liquefaction,43

Needle-LikeCrystals,58

PopcornTime,18–19

SandDunes,112–113

Sunflowers(GrowYourOwn),98–99

TemperatureGradients,110–111

TornadoinaBottle,72–73

WalkThroughTime,17

agricultureandfarming,1,4,83,87,93,94

animals,16,23–24,76,87,88,89,90–91,92–94,103,104–107,113

Arkansas,29,76

B

basins,12,101

bighornsheep,24

bison,89,92–93

C

California,10,24,42

canals,78,101,107

cavesandcaverns,29,42,46–49,58

cirques,26,27

climate,22,26,52–53,59–70,71.Seealsotemperature;weather

Colorado,2,20,25,49,67,78,80,87

corn,1,45,94

CratersoftheMoonNationalMonument,8

craton,11,12,13,14,17,45–46

D

dams,77,81

drumlins,56

E

earthlayers,3,6–7,11–12,41

earthquakes,3,6,8,10,14,37–42

ecosystems,3,86–94

environmentalissues,104–105

erosion,6,12,13,16,21,22,94

F

farmingandagriculture,1,4,83,87,93,94

fires,89,93

fishandfishing,23,76,78,104–107,111

FlintHillsNationalWildlife

Refuge,93

floods,81–83,85

Florida,67

forbs,87,90

G

geography,1–4.Seealsoagricultureandfarming;basins;cavesandcaverns;climate;lakes;mountains;plains;rivers;valleys

geology,1–4.Seealsoearthquakes;geysersandhotsprings;platetectonics;rocks;volcanoes

geysersandhotsprings,33–35,37,44

GlacierNationalPark,22,26,27,28

glaciers,14,22,26–28,41,46,50–56,57,103

goldeneagles,24

GrandTetonNationalPark,28

grass,45,86,87–89,93,97

GreatLakes,1,3,12,62,63,78,100–109,111

grizzlybears,24

gypsum,47

H

hangingvalleys,28

horns,28

hotspots,10,36

hydroelectricenergy,81

I

ice,50–54,56.Seealsoglaciers

IceAge,52–53

Idaho,8,34,49

igneousrocks,11,13,15,16,22

Illinois,2,25,49,52,68,75,76,78,80,83,87

Indiana,2,25,49,68

invasivespecies,105–108,113

Iowa,2,12,25,67,76,77,87,93

IsleRoyaleNationalPark,55,56

J

jetstreams,63

K

Kansas,2,12,25,29,67,68,87,93

Kentucky,49,76

kettles,56,57

L

LakeErie,101,102,103,104

LakeHuron,101,105,106,107

LakeMichigan,78,101,102,103,105,106

LakeOntario,101,103

lakes,1,3,12,14,26,27,55,57,62,63,78,100–109,111

LakeSuperior,12,62,100,101,102,103

levees,81,82,83,85

LewisandClarkexpedition,77

limestone,29,46–48,58

liquefaction,41–42,43

locusts,91–92

Louisiana,67,76

M

magma,8,10,11,16,33,34,36

maps,2,11,12,13,22,29,34,39,53,60,61,67,70,74,87,101

metamorphicrocks,11,13,15,16,22,54

Michigan,2,10,11,12,14,25,49,62,67,102

minerals,16,24,42,47,58

Minnesota,2,10,11,12,13,14,25,45,56,61,62,67,75–76,80,87,102

Mississippi,76

MississippiRiver,1,3,39,42,75–76,78,80,81–83,85,106–107

Missouri,2,12,14,25,29,38–39,41–42,49,52,68,76,77,78,82,83,87

MissouriRiver,75,76–77,78,81–83,85

Montana,2,25,34,76,78,87

moraines,28,55,56

mountaingoats,23

mountains,3,6,9,11,12,13,14,20–29,31,33,51,63,69,76.Seealsovolcanoes;specificmountainsandranges

N

NativeAmericans,77,92,108

NealSmithNationalWildlifeRefuge,93

Nebraska,2,12,25,62,67,77,78,87

NewMexico,87

NewYork,102

NorthAmericancraton,11,12,13,14,17,45–46

NorthDakota,2,25,61,77,78,87

O

Ohio,2,25,49,67,102

Oklahoma,29,67,87,93

P

Pennsylvania,102

plains,3,6,12,45–56.

Seealsoprairies

plants,1,16,45,86–90,93,94,95,97,98,106–107,108,113

plateaus,29

platetectonics,5–16,17,21,31,36,42,46,103

pollution,104–105

prairiedogs,90–91

prairies,86–94,95,98

pronghorn,94

ptarmigans,23

R

radiometricdating,15,19

rain,34,47–48,61,70,75,81,82,83,87,88.SeealsoThunderstorms

riftsandrifting,8,12,14,17,36,42,103

rivers,1,3,14,29,39,42,55,74–83,85,101,103,104–105,106–107.

rocks,3,10,11,12,13,14,15,16,17,19,21–22,28,29,31,33,45–46,46–48,

54–55,58

RockyMountainNational

Park,27,28,69

RockyMountains,3,13,20–23,25,26–28,33,51,63,69,76

S

sealampreys,105–106

sedimentaryrocks,12,14,15,22,46

shipsandboats,79,108–109

snow,26,27,29,34,50,61,62,63,69,70,81,82,83.Seealsoice

soil,4,41–42,43,81,94.Seealsoerosion

SouthDakota,2,25,47,49,62,67,77,87

stalagmitesandstalactites,42,48

steamboats,79

T

tectonics,plate,5–16,17,21,31,36,42,46,103

temperature,7,8,9,11,16,31,34,36,52,60–61,69,71,102,111.Seealsoclimate

Tennessee,76

Texas,67,87,91

thunderstorms,61,62,65,67

till,55,56

tornadoes,61,62,64–68,73

Twain,Mark(Samuel

Clemens),81

U

UpperMississippiRiverRefuge,76

u-shapedvalleys,27

V

valleys,6,26–28

volcanoes,6,8,9,10,11,12,14,21,32–37

VoyageursNationalPark,15,55

W

weather,61–70.Seealsoclimate;rain;snow;tornadoes

wetlands,104

wheat,1,45,94

wildlife.Seeanimals

WindCaveNationalPark,93

Wisconsin,2,11,12,14,25,49,52–53,55,56,62,76,80,87,102

WitchTree,109

Wyoming,2,20,25,34,37,78,87

YYellowstoneNationalPark,1,10,28,33–37,93

Z

zebramussels,106