1、ReadingUnit 2 Sailing the oceansPre-readingReadingScanningSkimmingDetailed readingHomeworkPre-readingThe four basic instruments for navigation:compass,astrolabe,sextant and nautical passcompassastrolabeastrolabesextantnautical chartnautical chartAnswer the questions.1.How do you think seamen found t
2、heir way before modern accurate methods of navigation were invented?Kept close to the shore,used nature such Kept close to the shore,used nature such as the sun,wind,birds,tide,etc,to help as the sun,wind,birds,tide,etc,to help them,and used some of the instruments them,and used some of the instrume
3、nts including a compass,astrolabe,etc.including a compass,astrolabe,etc.2.Which do you think was easier to work out:latitude or longitude?Latitude,because it was used to measure how far you had traveled from land on a straight line.It was discovered a long time before longitude.Read about what navig
4、ation was like before modern instruments were used.How did seamen explore the oceans before latitude and longitude made it possible to plot a ships position?Using nature l Keeping alongside the coastlinel Using celestial bodiesl Using wildlifel Using the weatherl Using the seaUsing celestial bodiest
5、o plot the positionsto work out the latitudea special cloud formation which indicates there is land close byUsing wildlifeIf seaweed was fresh and smelled strongly,the ship was close to land.Seabirds could be used to show the way to land when it was nowhere to be seen.Using the weatherTo help identi
6、fy the position of a stream or river when To direct their sailingUse the information to 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
7、speed.the North Star and the sunsea currents or tides andwindsUsing nature clouds,fresh seaweed,nesting birds returning home in the evening or fog What skills did sailors use to explore the seas and discover new lands?Using navigational instruments 1.Finding longitude 2.Finding latitudethe compassl
8、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)Read again and fill in the blanks.There were two methods to find longitude:1._ 2._ _measuring time and speedcompass and complicatedmathematical tablesUsing instruments Write down the working principles Write down
9、the working principles of the following instruments.of the following instruments.Bearing circle:Bearing circle:Astrolabe:Astrolabe:to compare the height to compare the height of the sun now with of the sun now with the position of the sun the position of the sun at midday.at midday.to compare the po
10、sition to compare the position of the ship in relation to of the ship in relation to some stars or the sun.some stars or the sun.Quadrant:Quadrant:a more precise form of the astrolabe,to a more precise form of the astrolabe,to measure how high stars are above the measure how high stars are above the
11、 horizon,and compare that horizon,and compare that measurement with previous measurement with previous measurements(using the ship as one of measurements(using the ship as one of the fixed points to find its position)the fixed points to find its position)Sextant:an updated version of the an updated
12、version of the quadrant and so it was more quadrant and so it was more accurate,to measure the accurate,to measure the angle between two fixed angle between two fixed points outside the ship(using points outside the ship(using two mirrors to find the ships two mirrors to find the ships position).pos
13、ition).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)Read the passage and answer the following questions.What is the use of a bearing circle,astrolabe,quadrant or sextant?()What is
14、 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 Skim the text and fill in the blanks.NatureCelestial bodies were used to _ the positions of navigators and to work out their _._ was
15、used to tell where the ship was close to land or to show the _ to land.plotlatitudeWildlifewayThe weather could help _ the position of a stream or river and to direct the sailing.Certain _ on the sea were used to carry ships to the destination.Navig-ational instru-mentsThe _ was used to help find lo
16、ngitude.The Bearing Circle,the Astrolabe,the Quadrant and the _ were used to find latitude.identifytides and currentscompasssextant1.Read the passage carefully and then answer the questions.1)Why are speed and time important in 1)Why are speed and time important in working out the longitude of a shi
17、p?working out the longitude of a ship?Speed and time are important in Speed and time are important in finding out the longitude of a ship finding out the longitude of a ship because the earth moves fifteenbecause the earth moves fifteen degrees westwards every hour.If you degrees westwards every hou
18、r.If you know your direction,speed and time,know your direction,speed and time,you can work out the approximate you can work out the approximate longitude or change in your position longitude or change in your position in relation to the stars.in relation to the stars.2)Why is the position of the su
19、n and various stars useful for working out latitude?The position of the sun and stars are 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.2.Suppose you were a sea c
20、aptain aiming 2.Suppose you were a sea captain aiming to sail round Africa.Discuss in groups.to sail round Africa.Discuss in groups.1)What skills would you seek in your 1)What skills would you seek in your sailors?sailors?2)What problems would you anticipate 2)What problems would you anticipate for
21、this journey?for this journey?What would you do if:Plan of actionYou were far from land and a storm arose.wait till the storm is over,and then find your new position and return to your original course3.Read the chart below and fill in your plans of action to deal with them.What would you do if:Plan
22、of actionYou knew your latitude but didnt know your longitude.use knots to find your speed and work out your approximate longitudeWhat would you do if:Plan of actionYou were blown off course.use the compass and the astrolabe,quadrant or sextant to find out your position,return to your former course
23、What would you do if:Plan of actionYou were offshore but you needed more food and water.follow nesting birds to shore;look for special cloud formations or fog over streams to find landWhat would you do if:Plan of actionYou wanted to keep a straight course.use a compassWhat would you do if:Plan of ac
24、tionYou were lost with no land in sight.measure your position using the sun or stars;look for sea birds,cloud formations,fog or seaweed to show that land is nearby4.Imagine you are on a boat with 4.Imagine you are on a boat with twenty-nine other people.You have twenty-nine other people.You have a s
25、mall box for your personal things a small box for your personal things but it can only hole ten items.What but it can only hole ten items.What would you need for a weeks journey would you need for a weeks journey across the North Sea to England?across the North Sea to England?CategoryItemsClothesHygiene BeddingGamessoapblanketcards,chessshirt,trousersCategoryItemsShoesToolsMedicinesBooksknife,scissorssea-sick tablets,cold medicinenovels,essay collectionswaterproof bootsHomework1.Review this passage.2.Preview Learning about language.
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