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Objectives1.了解人类早期的航海术。2.了解历史上著名的航海家、探险家及著名的航海事迹。3.学习表示“原因与结果”的用语。4.学习本单元的词汇。5.进一步复习掌握谓语的用法。WhenwewanttotalkaboutafamousnavigatorinChinesehistory,whowouldyouliketothinkoffirst?Apersonwhodirectstherouteorcourseofaship,aircraft,orotherformoftransportation,esp.byusinginstrumentsandmapsnavigatorNavigatorsorExplorersWhatisthedifferencebetweenanavigatorandanexplorer?Navigatorissomeonewhofindsthepositionandplotsthecourseofaship,anaircraft,acar,etc,usingmapsandinstruments.Navigatorseanautical(航海的)instrumentsfindnewislandsorcontinentsExplorerissomeonewhotravelsintoorthroughaplaceinordertolearnaboutit.Veryoftennavigatorsarealsoexplorers.ExplorerlanduseofcompassandlandmarksfindnewplaceswithinanalreadyidentifiedislandorcontinentHe(1371-1433)sailedfromChinatomanyplacesthroughoutSouthPacific,IndianOcean,PersianGulfanddistantAfricainsevenepicvoyagesfrom1405to1433,some80yearsbeforeColumbus'svoyages.ZhengHeHe(1254-1324)wasborninVenice.HeisprobablythemostfamousWesternertotraveltheSilkRoad.Hereachedfurtherthananyofhispredecessors,travellingbeyondMongoliaandintoChina.Finallyhisadventureswerewrittendownandthisbookwaspublishedandbecameabest-seller.MarcoPoloMarco’sTravelingMapMapofChinainYuanDynastyMarcoPolotraveledwithhisfathertoChinaduringtheYuanDynasty,whenKublaiKhanruledChina.MarcowassurprisedatChinesecustomsandskillssuchasusingcoalforheating,papermoney,noodle-makingandmanyotherthings.He(1728-1779)wasthegreatestBritainnavigator.HeenlistedintheRoyalNavyin1755.In1768hewaspromotedandsenttothePacificwherehesurveyedTahiti,NewZealand,andAustralia.Onhisfamous2ndexpedition(1772-75)heexploredAntarctica.In1776inhisthirdandfinalvoyage,heexploredtheWestcoastofNorthAmericaanddiscoveredtheHawaiianIslands.JamesCookHe(1451–1506)wasaSpanishsailor.Hemadefourvoyages.Heisfamousallovertheworldnow.PeopleconsiderhimtohavediscoveredAmericafirst.ColumbusThefourbasicinstrumentsfornavigation:Sinan,InchAstrolabe,Sextantandnauticalmap.Sinan,theancientChinesecompass.Pre-readingItwasinventedbyZhangHengintheHandynasty.Itismadeupofabronzefoundation(青铜地盘)andmagneticspoon(磁勺)whichismadeofnaturalmagnet,positionedrightinthecentralofthefoundation.Thehandleofthespoonpointstothesouth,whiletheothersidepointstothenorth.WhentheSinanisinthestill,thehandleofthespoonpointstothesouthbecauseofinfluenceoftheterrestrialmagnetism(地磁).Ithas17starslistedaswellasamapoftheskyoverhead(for37degrees)andtheecliptic(黄道).ThetimeofdayornightisontheoutsideedgewithnoonatthetopoftheAstrolabeandmidnightatthebottom.Itcomeswithacarryingchain,apouch,andabookonitsuse.Thereversesidehasasightformeasuringtheelevationsoftheheavenlybodies.astrolabesextantThesextantisanavigationalinstrumentformeasuringtheanglebetweenthehorizonandsomeobjectinthesky.Firstasailorlooksatthehorizonthroughaneyepiece.Atthesametimehecanseelightfromthesunorastarreflectedoffasmallmirrorontopoftheinstrument,ontoasecondmirrorandintotheeyepiece.Thenavigatorcanthenseetwoimages,thehorizonandthesunsidebyside.Hecanthenmeasuretheanglebetweenthemonascaleatthebottomoftheinstrument.Thescalegoesfrom0to120degrees.Anearlierinstrument,calledaquadrant,measuredinangleinthesamewaybutitcouldonlymeasureanglesfrom0to90degrees.sea/nautical/marinechartNauticalchartsaremapsofthedepthoftheseaandthecurrentsoftheoceans.Theyprovidemodernsailorswithroutesthroughtheseas,ratherlikeroadsthroughthecountryside.Theinformationbegantobecollectedinthenineteenthcenturyandhascontinuedtobeupdatedeversince.ThesechartswerenotavailabletoCaptainBlighorZhengHe.Whichonesdoyouthinkarestillusedtoday?Seachartsarestillusedtoday.1Howdoyouthinkseamenfoundtheirwaybeforemodernaccuratemethodsofnavigationwereinvented?Answerthequestions.Keptclosetotheshore,usednaturesuchasthesun,wind,birds,tide,etc,tohelpthem,andusedsomeoftheinstrumentsincludingacompass,astrolabe,etc.2Whichdoyouthinkwaseasiertoworkout:latitudeorlongitude?Latitude,becauseitwasusedtomeasurehowfaryouhadtravelledfromlandonastraightline.Itwasdiscoveredalongtimebeforelongitude.