Unit2Sailingtheoceans,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.byusinginstrumentsandmapsnavigator,NavigatorsorExplorersWhatisthedifferencebetweenanavigatorandanexplorer?,Navigatorissomeonewhofindsthepositionandplotsthecourseofaship,anaircraft,acar,etc,usingmapsandinstruments.Navigatorseanautical(航海的)instrumentsfindnewislandsorcontinents,Explorerissomeonewhotravelsintoorthroughaplaceinordertolearnaboutit.Veryoftennavigatorsarealsoexplorers.Explorerlanduseofcompassandlandmarksfindnewplaceswithinanalreadyidentifiedislandorcontinent,He(1371-1433)sailedfromChinatomanyplacesthroughoutSouthPacific,IndianOcean,PersianGulfanddistantAfricainsevenepicvoyagesfrom1405to1433,some80yearsbeforeColumbus'svoyages.ZhengHe,He(1254-1324)wasborninVenice.HeisprobablythemostfamousWesternertotraveltheSilkRoad.Hereachedfurtherthananyofhispredecessors,travellingbeyondMongoliaandintoChina.Finallyhisadventureswerewrittendownandthisbookwaspublishedandbecameabest-seller.MarcoPolo,Marco’sTravelingMap,MapofChinainYuanDynastyMarcoPolotraveledwithhisfathertoChinaduringtheYuanDynasty,whenKublaiKhanruledChina.MarcowassurprisedatChinesecustomsandskillssuchasusingcoalforheating,papermoney,noodle-makingandmanyotherthings.,He(1728-1779)wasthegreatestBritainnavigator.HeenlistedintheRoyalNavyin1755.In1768hewaspromotedandsenttothePacificwherehesurveyedTahiti,NewZealand,andAustralia.Onhisfamous2ndexpedition(1772-75)heexploredAntarctica.In1776inhisthirdandfinalvoyage,heexploredtheWestcoastofNorthAmericaanddiscoveredtheHawaiianIslands.JamesCook,He(1451–1506)wasaSpanishsailor.Hemadefourvoyages.Heisfamousallovertheworldnow.PeopleconsiderhimtohavediscoveredAmericafirst.Columbus,Thefourbasicinstrumentsfornavigation:Sinan,InchAstrolabe,Sextantandnauticalmap.Sinan,theancientChinesecompass.Pre-reading,ItwasinventedbyZhangHengintheHandynasty.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.astrolabe,sextant,Thesextantisanavigationalinstrumentformeasuringtheanglebetweenthehorizonandsomeobjectinthesky.Firstasailorlooksatthehorizonthroughaneyepiece.Atthesametimehecanseelightfromthesunorastarreflectedoffasmallmirrorontopoftheinstrument,ontoasecondmirrorandintotheeyepiece.,Thenavigatorcanthenseetwoimages,thehorizonandthesunsidebyside.Hecanthenmeasuretheanglebetweenthemonascaleatthebottomoftheinstrument.Thescalegoesfrom0to120degrees.Anearlierinstrument,calledaquadrant,measuredinangleinthesamewaybutitcouldonlymeasureanglesfrom0to90degrees.,sea/nautical/marinechart,Nauticalchartsaremapsofthedepthoftheseaandthecurrentsoftheoceans.Theyprovidemodernsailorswithroutesthroughtheseas,ratherlikeroadsthroughthecountryside.Theinformationbegantobecollectedinthenineteenthcenturyandhascontinuedtobeupdatedeversince.ThesechartswerenotavailabletoCaptainBlighorZhengHe.,Whichonesdoyouthinkarestillusedtoday?Seachartsarestillusedtoday.,1Howdoyouthinkseamenfoundtheirwaybeforemodernaccuratemethodsofnavigationwereinvented?Answerthequestions.Keptclosetotheshore,usednaturesuchasthesun,wind,birds,tide,etc,tohelpthem,andusedsomeoftheinstrumentsincludingacompass,astrolabe,etc.,2Whichdoyouthinkwaseasiertoworkout:latitudeorlongitude?Latitude,becauseitwasusedtomeasurehowfaryouhadtravelledfromlandonastraightline.Itwasdiscoveredalongtimebeforelongitude.,Thankyou!
