Post on 03-Jul-2020
CHAPTER 1
Wheelsareallaroundus.Youusethemeveryday,butyouprobablydon’tthinkaboutthemveryoften.Infact,thewheelasweknowitisquiteanewinvention.
Therearenorealwheelsinnature.Therearen’tanyanimalsthatusewheelstogetaround.Butwhynot?Whyaretherenoanimalswithwheelsinsteadoflegs?Perhapsbecausewheelsaren’tanygoodonsomekindsofground.It’shardtocrossthedesertortheforestortoclimbamountainonwheels.However,forhumans,thewheelhasbeenanamazinginvention.
Inventing the WheelIT’S A MAN-MADE INVENTION, IT HAS COMPLETELY CHANGED THE WAY WE LIVE, AND IT’S EVERYWHERE IN THE WORLD. WHAT IS IT? THE WHEEL!
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Iftherearenowheelsinnature,howdidpeoplefirstmakethem?Nobodyreallyknowstheanswer.Therearemanyroundshapesandcirclesinnature,buttheyaren’tlikewheels;theyaren’tusedtohelpmovethings.
Theearliestpeopleworkedwithstone.So,maybetheysawroundstonesrolling.Buttheyalsomadeboatsfromwood.Perhapstheysawthelogstheyusedforbuildingboatsrollingdownahill!
OneoftheearliestusesoflogstomovethingswasinEgyptabout3000BCE.Logswereusedtobuildthepyramids.Theheavystonesforthesebuildingswereputonflatsledsandpulledforwardoverlogs,calledrollers.Therollinglogshelpedmovethestonesmoreeasily.
Inventing the WheelIT’S A MAN-MADE INVENTION, IT HAS COMPLETELY CHANGED THE WAY WE LIVE, AND IT’S EVERYWHERE IN THE WORLD. WHAT IS IT? THE WHEEL!
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ThefirstrealwheelswereprobablymadeinMesopotamia,nowIraq.Butscientiststhinkthatthosefirstwheelswerenotusedformovingavehicle.Theywereusedinpotterywheels.Thesemachinesturnedquicklyinacircletohelppeoplemakethingslikecupsandbowls.Anotherearlywheel,amillstone,wasaheavy,roundstone.Itwasusedforbreakingdownplantsforcookingandformaking flour.1
TheearliestpicturesofwheelsonvehiclesareonMesopotamianpaintingsfrom3000–2700BCE.Thesewheelsweremadeofsolid2woodandturnedonasimpleaxle.Around2000BCEtheEgyptiansstartedusingspokesontheirchariotwheels.Thesewheelsneededlesswood,sotheywerecheapertomake.Theywerealsomuchlighterandcouldtravelfaster.
1� our:usedtomakebread,cakes,etc.2solid:withoutanyholesoropenings
The fi rst wheels were solid wood.
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ThewheelwassoonusedbydifferentgroupsofpeopleacrossEuropeandAsia.By500BCE,manytypesofwheeledvehicleswereinuse,fromfastchariotstolarge,slowcarts.3Thewheelstheyusedaremuchlikethewheelsweusetoday.
However,inotherplacesintheworld,wheelswereneverused.CentralandSouthAmericanpeoples,liketheMayansorIncas,builtamazingcitiesandtempleswithoutusingwheels.Nobodyknowswhy,butitmaybebecausetheylivedinmountainousareas,whereitwasimpossibletousewheeledvehicles.
Wheelsarenogoodinhighmountains,indeepsnow,orindesertsands.EventodayintheSaharadesert,animalslikethecamelaremoreusefulthanwheeledvehicles.3cart:avehiclewithtwoorfourwheelsthatispushedbyapersonorpulledbyananimal
4all-terrain vehicle:avehiclethatcantravelonmanydifferentkindsofground
Video QuestLegs or Wheels: part 1Watch this video about some men trying to make a new kind of all-terrain vehicle.4 What is the 4 What is the 4
idea behind the new invention?
A Mayan temple
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Throughouthistorymachineshaveusedwheels.Andforalongtimewheelsalsomademachineswork.Thefirstwheelusedforpowerwasthewaterwheel.Thiswasagreatimprovementintechnologybecauseitletpeopleuserunningwatertopowermachinesinsteadofusinganimalsorotherpeople.
ThefirstwaterwheelweknowaboutwasinaflourmillinByzantium,nowTurkey.Thefirstwaterwheelslayontheirsides.Butby240CE,inAlexandriainEgypt,peoplewereusingwheelsthatstoodupinriversandweremuchmorepowerful.
Making Wheels WorkTHE WHEEL IS BEST KNOWN FOR ITS USE IN VEHICLES, BUT IT WAS FIRST USED IN INDUSTRY.
CHAPTER 2
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Tousewaterwheelstodrivemachines,peopleneededawaytosendthepowerfromtheturningwheeltothethingstheywantedtoworkon.Theyusedmorewheels!Theyfoundthatifyoucutteethintotwowheelsandputthemtogether,thefirstwheelturnsthesecondone.
Asearlyas330BCE,theGreekinventorArchimedestalkedabouttoothedwheels,calledgears.Herealizedthatwhentheteethfromthefirstwheelpushthesecond,thesecondwheelturnsintheoppositedirection.Butathirdwheelmovesoppositetothesecond,inthesamedirectionasthefirstone.Byputtinggearstogether,youcansendthepowerfromawaterwheeltoamachine.TheGreeksusedgearstomakecomplicatedmechanisms5likeclocks.
5mechanism:onepartofamachinethatdoesaspecialjob
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PerhapsthemostcomplicatedearlyuseofgearsthatweknowaboutistheAntikytheraMechanism.Itwasfoundundertheseainashipwreck6neartheGreekIslandofAntikytherain1901.TherewasacasewithinstructionsinGreek,30gears,and82piecesmadeofthemetalbronze.
Scientiststhoughtthatthesepieceswerepartofaverycomplicatedkindofclock,butittookthemalmost100yearstoputthepiecestogether!Infact,theAntikytherawasaplanetarium,amachinethatshowsthemovementsoftheplanets7andthemoonaroundthesun.Itwasactuallyakindofcalendar.Itshowedscientiststhattheancientworldhadcomplicatedtechnologyandknewalotabout space.
6shipwreck:ashipthatsankinanaccident7planets:verybig,roundthings,likeEarth,thatmovearoundastar
Drawing of the Antikythera Mechanism
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UNDERSTANDDescribe two ways wheels were used in the past.Describe two ways wheels were used
Anotherimportantwheelforindustrywasthewindmill.Windmillsusesailstocatchthewindandmakepower.Unfortunately,windmillsonlyworkifit’swindy!Buttheyhaveonegreatadvantage.Waterwheelsneedrivers,butyoucanbuildawindmillanywherethat’swindy.Modernwindmills,calledwindturbines,areusedasacleanwaytomakeelectricity.
Finally,steampower,thekeytotheIndustrialRevolution,8alsousedthewheel.Steamfromboilingwatermovedwheelsandpoweredmachines.Fromthe17thcentury,steampowerwasseenmoreandmoreinmillsandfactories.Bythe19thcentury,steamwaspoweringthenewtrainsandshipsanddrivingforwardtrade9andindustry.Theageofindustrialpowerhadbegun!
8Industrial Revolution:thetimeinhistorywhenmachinesinbigfactoriesstarteddoingalotofwork
9trade:buyingandsellingthings
A windmill with sails
A steam engine
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Wheelsmakemoderntransportationpossible.Therearebigwheels,smallwheels,fastwheels,slowwheels.Let’stakealookatsomefactsaboutwheels,andsomeoftheinventionsthathavemadethembetter.
Small wheelsThesmallestmotorvehicleyoucandriveonaroad
isthePeelP50.Itwasfirstbuiltinthe1960sontheIsleofManbetweenEnglandandIreland,butonly50weremade.TheP50hadonlythreewheels,wasverylight,andhadjustonefrontlightandonedoor.Itcouldonlydriveforward.Ifyouwantedtogobackward,youhadtopullitbyhand.Butitwassmallenoughtokeepinyourhouse!
A World Full of Wheels!WE SEE WHEELS EVERYWHERE WE LOOK.
CHAPTER 3
A bucket wheel excavator moving earth
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Big wheelsThebiggestvehicleintheworldisthebucket-wheel
excavator.Thesemachinesuseverybigwheelstomovelargepiecesofearth.Thebiggest,theBagger293,is96meterstalland225meterslong,anditweighs142,000kilograms!Itswheelis21metersacross!Butitcanonlymoveveryslowly,travelingjusthalfakilometeranhour!
Lots of wheelsTheroadvehiclewiththemostwheelsisthe
articulatedtruck.Thesebig,heavyvehiclescarryfood,animals,gas,andmanyotherthings.Theyoftenhavefiveaxlesandeighteenwheelsandaresometimesknownas18-wheelers.Onlythefronttwowheelsarelikethewheelsonanormalcar.Theothersixteenwheelssitinpairsonfouroftheaxles.Thismakesthevehiclesafer.
An articulated truck
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Cambridge University Press978-1-107-66739-6 - Cambridge Discovery EducationTM: Interactive Readers: The Wheel: A2+
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