《标出船只的位置》PPT课件

《《标出船只的位置》PPT课件》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、SailingtheoceansUnit2Nowadayshowdothesailorsknowthedirectionofnavigationinthesea?JamesCook(1728-1779)MarcoPolo1254-1324ZhengHe1371-1433Howdoyouthinkseamenfoundtheirwaybeforemodernaccuratemethodsofnavigationwereinvented?compassastrolabesextantNauticalchartsThecompassisu

2、sedtohelpfindthedirectionthattheshipneedstogo.Theastrolabemeasurestheheightandpositionofthesun.Thesextantisanavigationalinstrumentformeasuringtheanglebetweenthehorizonandsomeobjectinthesky.Nauticalchartsaremapsofthedepthoftheseaandthecurrentsoftheoceans.Theyprovidesail

3、orswithroutesthroughtheseas.Whatdidancientsailorsusetohelpthemselvesnavigateonearth?ReadingUsenaturetohelpUsenavigationalinstrumentstohelpReadthepassageandusetheinformationtoanalysethenavigationalskills.Writetheanswersinyourownwords.ReadingUsingnature1.Tofindtheship’sp

4、ositionatsea,asailorused_____________________.2.Asailorknewthatlandwasnearbyifhesaw____________________________________________.3.Sailorsused________________________________toincreasetheirspeed.theNorthStarandthesunfreshseaweed,nestingbirdsreturninghomeintheeveningorfo

5、gseacurrentsortidesandwindsReadingUsinginstruments4.Thereweretwomethodstofindlongitude:①_________________________②_______________________.5.Whatistheuseofabearingcircle,astrolabe,quadrantorsextant?()Whatistheuseofacompass?()AtosetthecourseoftheshipBtomeasuretheposition

6、oftheshipCtomeasurethespeedoftheshipDtotellthetimemeasuringtimeandspeedUsingcompassandcomplicatedmathematicaltablesBAReading5.Thereadingpassagemainlywantstotellus_______.A.thatkeepingalongsidethecoastlineisfirstthemostusefulformofexploration.B.abouttheskillsandnavigati

7、onalaidsearlyseamenusedwhilesailingtheoceans.C.thatfindinglongitudeandlatitudeisamusttoplotaship’spositiononamap.D.thatthereisusefulinformationinanencyclopedia.BReadingThesailorswouldneedtobeexcellentnavigators,abletocopewithbothhotandcoldweather,experiencedinsailingth

8、roughverybadweatherandabletocooperateinateam.Whatskillswouldyouseekinyoursailors?DiscussionLanguagepoints标出船只的位置受---的