陕西省定边县第四中学高中英语 Unit 2 Sailing the oceans Reading课件 新人教版选修9.ppt

unit2sailingtheoceans reading warmingup pre reading reading scanning skimming detailedreading homework warmingup indianocean pacificocean atlanticocean arcticocean question howmanyoceansarethereintheworld ferdinandmagellan费迪南德 麦哲伦 whatisanavigator anavigatorexploresnewroutesacrossthesea vascodagama瓦斯科 达伽马 christophercolumbus克里斯托弗 哥伦布 whatisthedifferencebetweenanavigatorandanexplorer navigator sea nauticalinstruments findnewislandsorcontinents anavigatorexploresthesea explorer land usecompassandlandmarks findnewplaceswithinanalreadyidentifiedislandorcontinent anexplorerdiscoversnewplacesonland zhenghe marcopolo jamescook lookatthesefamouspeople aretheynavigatorsorexplorers whatdoyouknowaboutthem zhenghe1371 1433 heledalargefleettoexploresoutheastasia indiaandthemiddleeastinthemingdynasty altogetherhemade7voyagesinthe15thcentury hetravelledmorethan50 000kmandvisited30countriesnewtochinaanddevelopedmanytradelinks heisconsideredoneoftheearliestnavalexplorersinchinesehistory marcopolo1254 1324 heisthemostfamouswesternertotravelthesilkroadandtheonlypersontoprovideinformationaboutchinatotheoutsideworld in1271hesetouttoreachthemongolempireandthenchina in1295 hearrivedbackineurope threeyearslaterhewasimprisonedbythegenoese whileinprison hetoldthestory ofhistravelstoafellowprisonerwhowrotehisadventuresdown whenhisbookwaspublisheditbecameabest seller themapofmarcopolo svoyage jamescook 1728 1779 jamescook 1728 1779 wasthegreatestbritainnavigator cookjoinedintheroyalnavyin1755 in1768hewaspromotedandsenttothepacificwherehesurveyedtahiti newzealand andaustralia onhisfamoussecondexpedition 1772 1775 heexploredantarctica in1776heundertookhisthirdandfinal voyageinwhichheexploredthewestcoastofnorthamericaandtriedtolocateapassagebetweentheatlanticandpacificoceans onthisvoyagehediscoveredthehawaiianislands andsailedupthecoastofnorthamericathroughtheberingstraitstothearcticocean onhisreturnhewaskilledbyhawaiianislanders heisregardedasoneoftheworld sgreatestexploresandnavigators pre reading thefourbasicinstrumentsfornavigation sinan inchastrolabe sextantandnauticalmap sinan theancientchinesecompass astrolabe sextant nauticalchart answerthequestions 1 howdoyouthinkseamenfoundtheirwaybeforemodernaccuratemethodsofnavigationwereinvented keptclosetotheshore usednaturesuchasthesun wind birds tide etc tohelpthem andusedsomeoftheinstrumentsincludingacompass astrolabe etc 2 whichdoyouthinkwaseasiertoworkout latitudeorlongitude latitude becauseitwasusedtomeasurehowfaryouhadtraveledfromlandonastraightline itwasdiscoveredalongtimebeforelongitude 3 canyouidentifytheseearlynavigationalinstrumentsseamenusedandexplainhowtheyareused 1 compass inancientchina 2 astrolabe3 sextant4 sea nautical marinechart 4 whichonesdoyouthinkarestillusedtoday seachartsarestillusedtoday sailingtheoceans readaboutwhatnavigationwaslikebeforemoderninstrumentswereused scanning howdidseamenexploretheoceansbeforelatitudeandlongitudemadeitpossibletoplotaship sposition page1 usingnature keepingalongsidethecoastlineusingcelestialbodiesusingwildlifeusingtheweatherusingthesea usingcelestialbodies toplotthepositions toworkoutthelatitude aspecialcloudformationindicatesthereislandcloseby northstar sun clouds usingwildlife ifseaweedwasfreshandsmelledstrongly theshipwasclosetoland seabirdscouldbeusedtoshowthewaytolandwhenitwasnowheretobeseen seaweed birds usingtheweather fog tohelpidentifythepositionofastreamorriverwhen todirecttheirsailing winds usetheinformationtoanalyzethenavigationalskillsandwritetheanswersinyourownwords tofindtheship spositionatseaasailorused asailorknewthatlandwasnearbyifhesaw sailorsused toincreasetheirspeed thenorthstarandthesun seacurrentsortidesand winds usingnature clouds freshseaweed nestingbirdsorfog whatskillsdidsailorsusetoexploretheseasanddiscovernewlands page2 usingnavigationalinstruments 1 findinglongitude 2 findinglatitude thecompass thebearingcircle 方位圆 theastrolabe 星盘 thequadrant 象限仪 四分仪 thesextant 六分仪 readagainandfillintheblanks thereweretwomethodstofindlongitude 1 2 measuringtimeandspeed compassandcomplicated mathematicaltables usinginstruments writedowntheworkingprinciplesofthefollowinginstruments bearingcircle astrolabe tocomparetheheightofthesunnowwiththepositionofthesunatmidday tocomparethepositionoftheshipinrelationtosomestarsorthesun quadrant amorepreciseformoftheastrolabe tomeasurehowhighstarsareabovethehorizon andcomparethatmeasurementwithpreviousmeasurements usingtheshipasoneofthefixedpointstofinditsposition sextant anupdatedversionofthequadrantandsoitwasmoreaccurate tomeasuretheanglebetweentwofixedpointsoutsidetheship usingtwomirrorstofindtheship sposition horizon sunheight abearingcircle bearingthesun heightandazimuth themarkswereusedtomeasuretheshadowofthesunanditsheightandpositioninthesky 方位 readthepassageandanswerthefollowingquestions whatistheuseofabearingcircle astrolabe quadrantorsextant whatistheuseofacompass a tosetthecourseoftheshipb tomeasurethepositionoftheshipc tomeasurethespeedoftheshipd totellthetime b a usinginstruments skimming 1 skimthetextandfillintheblanks plot latitude wildlife way identify tidesandcurrents compass sextant 2 decidewhetherthefollowingstatementsaretrue t orfalse f 1 itwasnotuntilthe17thcenturythattherewassecuremeansofmeasuringlongitude 2 inthe12thcenturyseamenbegantousethecompasstosetthecourseoftheship t t 3 theuseofabearingcircle astrolabe quadrantorsextantistomeasurethespeedoftheship 4 theastrolabewasthefirstinstrumenttomeasurethepositionofthesun 5 thefresherseaweedintheseawas thefarthertheshipwastoland 6 thesextantwasthemostpreciseandreliableoftheearlynavigationalinstruments f f f t detailedreading 1 readthepassagecarefullyandthenanswerthequestions 1 whyarespeedandtimeimportantinworkingoutthelongitudeofaship speedandtimeareimportantinfindingoutthelongitudeofashipbecausetheearthmovesfifteen degreeswestwardseveryhour ifyouknowyourdirection speedandtime youcanworkouttheapproximatelongitudeorchangeinyourpositioninrelationtothestars 2 whyisthepositionofthesunandvariousstarsusefulforworkingoutlatitude thepositionofthesunandstarsareusefulforworkingoutlatitudebecausetheyarefixedpointsintheskyandtheirmovementsinrelationtotheeartharealreadyknown sotheycanbeusedtomeasureaship sposition 2 supposeyouwereaseacaptainaimingtosailroundafrica discussingroups 1 whatskillswouldyouseekinyoursailors 2 whatproblemswouldyouanticipateforthisjourney waittillthestormisover andthenfindyournewpositionandreturntoyouroriginalcourse 3 readthechartbelowandfillinyourplansofactiontodealwiththem useknotstofindyourspeedandworkoutyourapproximatelongitude usethecompassandtheastrolabe quadrantorsextanttofindoutyourposition returntoyourformer