高中英语人教版选修9课件：UNIT 2《SAILING THE OCEANS》WARMING-UP&READING4（33张PPT） WORD版含解析.ppt

1、(5 minutes)SailingQuestion:How many oceans are there in the world?Pacific OceanAtlantic OceanIndian OceanArctic Oceanworld map explorationWrite down the words you know,which are related to navigation and sea.sail,sailor,voyage,latitude,longitude,equator,horizon,captain,land island,nautical middles,e

2、xplore,explorationseaman,seaweed,seafood,shore,offshore,onshore,beach,beach-ball,seabed,sea-bird,seagull,sea shell,seaside,sea water,seasick,coast,coastline,tide,wave,current(5 minutes)compassAstrolabe(星盘)Sextant(六分仪)sea/nautical chartnavigatorsearly navigational instruments1.What is a navigator?2.W

3、hat is the difference between a navigator and an explorer?A navigator explores new routes across the sea.A navigator explores the sea;an explorer discovers new places on land.Zheng HeIs he a navigator or an explorer?He made seven voyages during his lifetime and contributed greatly to the science of

4、navigation in China.Zheng HeMarco PoloJames CookHow do you think seaman found their way before modern accurate methods of navigation were invented?How did they navigate so well?Read about what navigation was like before modern instruments were used.(25 minutes)Sailing the oceans Fast-reading to get

5、the general idea.Page 1(10 minutes)Using nature l Keeping alongside the coastlinel Using celestial bodiesl Using wildlifel Using the weatherl Using the sea(1 minute)Using celestial bodiesto plot the positionsto work out the latitudea special cloud formation indicates there is land close by(2 minutes

6、)Using wildlifeIf seaweed was fresh and smelled strongly,the ship was close to land.Sea birds could be used to show the way to land when it was nowhere to be seen.(1 minute)Using the weatherTo help identify the position of a stream or river whenTo direct their sailing(1 minute).Use the information t

7、o analyze the navigational skills and write the answers in your own words.1.To find the ships position at sea a sailor used _.2.A sailor knew that land was nearby if he saw_ _.3.Sailors used _ _ to increase their speed.the North Star and the sun.sea currents or tides andwindsUsing nature clouds,fres

8、h seaweed,nesting birds or fog(5 minutes)Fast-reading to get the general idea.then answer the questions.Page 2(10 minutes)Using navigational instruments 1.Finding longitude 2.Finding latitudethe compassl the bearing circle (方位圆)l the astrolabe (星盘)l the quadrant (象限仪,四分仪)l the sextant (六分仪)(2 minute

9、s)Read the passage and answer the following questions.1.What is the use of a bearing circle,astrolabe,quadrant or sextant?()What is the use of a compass?()A.to set the course of the ship B.to measure the position of the ship C.to measure the speed of the ship D.to tell the timeBAUsing instruments(2

10、minutes)Read again and fill in the blanksThere were two methods to find longitude:1._ 2._measuring time and speedcompass and complicatedmathematical tablesUsing instruments(1 minute)Write down the working principles of the following instruments:Bearing circle:Astrolabe:Quadrant:Sextant:to compare th

11、e height of the sun now with the position of the sun at midday.to compare the position of the ship in relation to some stars or the sun.a more precise form of the astrolabe,to measure how high stars are above the horizon,and compare that measurement with previous measurements.an updated version of t

12、he quadrant and so it was more accurate,to measure the angle between tow fixed pints outside the ship.(5 minutes)horizonSun heightA Bearing CircleBearing the sun-height and azimuth (The marks were used to measure the shadow of the sun and its height and position in the sky.)(方位)Listen to the tape an

13、d then answer the questionsDetailed readingPage 2(5 minutes)1.Why are speed and time important in working out the longitude of a ship?Because the earth moves fifteen degrees westwards every hour.If you know your direction,speed and time,you can work out the approximate longitude.2.Why is the positio

14、n of the sun and various stars useful for working out latitude?Because they are fixed points in the sky and their movements in relation to the earth are already known.So they can be used to measure a ships position.(10 minutes)What would you do if you came across the following problems during your v

15、oyage?What would you do if:Plan of actionYou were far from land and a storm arose.You knew your latitude but didnt know your longitude.You were blown off-course.You were offshore but you needed more food and water.You wanted to keep a straight course.You were lost with no land in sight.wait till the

16、 storm is over,and then find your new position and return to your original courseuse knots to find your speed and work out your approximate longitudeuse the compass and the astrolabe,quadrant or sextant to find out your position,return to your former course.follow nesting birds to shore;look for special cloud formations or fog over streams to find landuse a compassmeasure your position using the sun or stars;look for sea birds,cloud formations,fog or seaweed to show that land is nearby-(10 minutes)Homework1.Review this passage.2.Preview Learning about language.