高中英語 Sailing the oceansReading課件 新人教選修9

1、2021/8/11 星期三1Reading2021/8/11 星期三2The four basic instruments for navigation: Sinan, Inch Astrolabe, Sextant and nautical map.Sinan, the ancient Chinese compass. 2021/8/11 星期三3It was invented by Zhang Heng in the Han dynasty. It is made up of a bronze foundation (青銅地盤) and magnetic spoon(磁勺) which i

2、s made of natural magnet, positioned right in the central of the foundation. 2021/8/11 星期三4The handle of the spoon points to the south, while the other side points to the north. When the Sinan is in the still, the handle of the spoon points to the south because of influence of the terrestrial magnet

3、ism (地磁). 2021/8/11 星期三5 It has 17 stars listed as well as a map of the sky overhead (for 37 degrees) and the ecliptic (黃道). The time of day or night is on the outside edge with noon at the top of the Astrolabe and midnight at the bottom. It comes with a carrying chain, a pouch, and a book on its us

4、e. The reverse side has a sight for measuring the elevations of the heavenly bodies.astrolabe2021/8/11 星期三6sextant2021/8/11 星期三7The sextant is a navigational instrument for measuring the angle between the horizon and some object in the sky. First a sailor looks at the horizon through an eyepiece. At

5、 the same time he can see light from the sun or a star reflected off a small mirror on top of the instrument, onto a second mirror and into the eyepiece. 2021/8/11 星期三8The navigator can then see two images, the horizon and the sun side by side. He can then measure the angle between them on a scale a

6、t the bottom of the instrument. The scale goes from 0 to 120 degrees. An earlier instrument, called a quadrant, measured in angle in the same way but it could only measure angles from 0 to 90 degrees.2021/8/11 星期三9nautical chart2021/8/11 星期三10Nautical charts are maps of the depth of the sea and the

7、currents of the oceans. They provide modern sailors with routes through the seas, rather like roads through the countryside. The information began to be collected in the nineteenth century and has continued to be updated ever since. These charts were not available to Captain Bligh or Zheng He.2021/8

8、/11 星期三11Discuss1. How do you think seamen found their way before modern accurate methods of navigation were invented?Kept close to the shore, used nature such as the sun, wind, birds, tide, etc, to help them, and used some of the instruments including a compass, astrolabe, etc.2021/8/11 星期三122. Whi

9、ch 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.2021/8/11 星期三133. Can you identify these early navigational instruments seamen used and explain

10、 how they are used?1) compass ( in ancient China)2) astrolabe3) sextant4) sea / nautical / marine chart2021/8/11 星期三144. Which ones do you think are still used today?Sea charts are still used today.2021/8/11 星期三151. Where do these materials come from?2. What did the early navigator use to help them

11、navigate?3. What natural objects were used to assist the navigation?4. Is it easier to measure longitude or latitude? 5. Do the astrolabe, the quadrant and the sextant mean the same thing?Read and answer these questions.2021/8/11 星期三16Comprehending1. Read the passage and answer the following questio

12、ns.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 timeAB2021/8/11 星期三172) Why are speed and time important in working

13、 out the longitude of a ship? Speed and time are important in finding 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 or change in your position in relation to the stars.2

14、021/8/11 星期三183) Why is the position of the sun 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 mea

15、sure a ships position.2021/8/11 星期三192. Suppose you were a sea captain aiming to sail round Africa. Discuss in groups:1) What skills would you seek in your sailors?2) What problems would you anticipate for this journey?2021/8/11 星期三20What would you do if : Plan of actionYou were far from land and a

16、storm arose.Wait till the storm is over, and then find your new position and return to your original course. 3. Read the chart below and fill in your plans of action to deal with them.2021/8/11 星期三21What would you do if :Plan of actionYou knew your latitude but didnt know your longitude.Use knots to

17、 find your speed and work out your approximate longitude.2021/8/11 星期三22What 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. 2021/8/11 星期三23What would you do if :Plan of actionY

18、ou 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 land. 2021/8/11 星期三24What would you do if :Plan of actionYou wanted to keep a straight course. Use a compass.2021/8/11 星期三25What would you do if :Plan of a

19、ctionYou 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 nearby.2021/8/11 星期三264. Read the passage again and use the information to analyze the navigational skills.2021/8/11 星期三27Using nature1. T

20、o find the ships position at sea a sailor used the North Star and the sun.2. A sailor knew that land was nearby if he saw _ _.3. Sailors used _ _to increase their speed. fresh seaweed, nesting birds returning home in the evening or fog sea currents or tides and winds2021/8/11 星期三284. There were two

21、methods to find longitude: 1)_ 2)_ Using instrumentsmeasuring time and speedcompass and complicated mathematical tables2021/8/11 星期三295 Write down the working principles of the following instruments: Bearing circle: Astrolabe: to compare the height of the sun now with the position of the sun at midd

22、ay. to compare the position of the ship in relation to some stars or the sun 2021/8/11 星期三30Quadrant: a more precise form of the astrolabe, to measure how high stars are above the horizon, and compare that measurement with previous measurements (using the ship as one of the fixed points to find its

23、position) 2021/8/11 星期三31Sextant:an updated version of the quadrant and so it was more accurate, to measure the angle between two fixed points outside the ship (using two mirrors to find the ships position). 2021/8/11 星期三32 5. Imagine you are on a boat with twenty-nine other people. You have a small

24、 box for your personal things but it can only hole ten items. What would you need for a weeks journey across the North Sea to England?2021/8/11 星期三33CategoryItemsClothesHygiene BeddingGamessoapblanketcards, chessshirt, trousers2021/8/11 星期三34CategoryItemsShoesToolsMedicinesBooksknife, scissorssea-sick tablets, cold medicinenovels, essay collectionswaterproof boots2021/8/11 星期三35Read the passage (Reading) and decide whether the following statements are true (T) or false (F).1. An early method of calculating longitude was to use a k