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1、SailingtheocenasReadaboutwhatnavigationwaslikebeforemoderninstrumentswereused.SailingtheoceansPage1Fast-readingHowdidseamenexploretheoceansbeforelatitudeandlongitudemadeitpossibletoplotaship’sposition?UsingnatureKeepingalongsidethecoastlineUsingcelestialbodiesU
2、singwildlifeUsingtheweatherUsingtheseaUsingcelestialbodiestoplotthepositionstoworkoutthelatitudeaspecialcloudformationindicatesthereislandclosebyUsingwildlifeIfseaweedwasfreshandsmelledstrongly,theshipwasclosetoland.Seabirdscouldbeusedtoshowthewaytolandwhenitwa
3、snowheretobeseen.UsingtheweatherfogTohelpidentifythepositionofastreamorriverwhen…TodirecttheirsailingReadthetextcarefullyandfillintheblanks.NatureCelestialbodieswereusedto_____thepositionsofnavigatorsandtoworkouttheir_______._______wasusedtotellwheretheshipwasc
4、losetolandortoshowthe____toland.plotlatitudeWildlifewayTheweathercouldhelp_______thepositionofastreamorriverandtodirectthesailing.Certain________________ontheseawereusedtocarryshipstothedestination.identifytidesandcurrentsPage2Fast-readingWhatskillsdidsailorsus
5、etoexploretheseasanddiscovernewlands?Usingnavigationalinstruments1.Findinglongitudethecompass2.Findinglatitudethebearingcircle(方位圓)theastrolabe(星盤)thequadrant(象限儀,四分儀)thesextant(六分儀)SunheighthorizonWritedowntheworkingprinciplesofthefollowinginstruments:Bearingc
6、ircle:tocomparetheheightofthesunnowwiththepositionofthesunatmidday.DetailreadingAstrolabe:tocomparethepositionoftheshipinrelationtosomestarsorthesunQuadrant:amorepreciseformoftheastrolabe,tomeasurehowhighstarsareabovethehorizon,andcomparethatmeasurementwithprev
7、iousmeasurements(usingtheshipasoneofthefixedpointstofinditsposition)Sextant:anupdatedversionofthequadrantandsoitwasmoreaccurate,tomeasuretheanglebetweentwofixedpointsoutsidetheship(usingtwomirrorstofindtheship'sposition).ComprehendingPage141.Readthepassageandan
8、swerthefollowingquestions.1)Whatistheuseofabearingcircle,astrolabe,quadrantorsextant?()Whatistheuseofacompass?()A.tosetthecourseoftheshipB.tomeasurethepositionoftheshipC.tom
