seaman, seaweed, seafood, shore, offshore, onshore, beach, beach-ball, seabed, sea-bird, seagull, seashell, seaside, sea water, seasick, coastline, tide, wave, current
sail, sailor, voyage, latitude, longitude, equator, horizon, captain, land island, nautical, explore, exploration
navigate vi. , , vt. , , ,
navigator n. ,
What is the difference between a navigator and an explorer? What is the difference between a navigator and an explorer (explore; exploration)?
navigatorseanautical instrumentsfind new islands or continentsA navigator is sb. who finds the position and plots the course of a ship by using maps and nautical instruments.
explorerland compass and landmarksfind new places within an already identified island or continentA explorer is sb. who travels into or through a place in order to learn about it. Very often navigators are also explorers.
Can you identify these early navigators\explorers?
Zheng HeMarco PoloJames CookChristopher Columbus
Zheng He, the most famous Chinese navigator, lived from 1371 to 1433 and made seven voyages around the South China Sea, visiting more than thirty countries. The people there gave him a warm welcome. And he not only spread Chinese culture, but also developed many trade links with the other countries.
In the years between 1405 and 1433, seven large treasure fleets sailed westwards on voyages of trade and exploration. Under the command of Zheng He, the fleets set sail from the South China Sea across the Indian Ocean to the Red Sea, and then traveled further south, discovering the eastern coast of Africa.
He renewed relations with the Kingdoms of the East African coast. One African king sent the Ming emperor a royal present: two giraffes.
Marco Polo was the only person to provide information about China to the outside world. His journey around Asia lasted 24 years. He reached further than any of his predecessors, travelling beyond Mongolia and into China. Finally he wrote his adventures down and his book was published and became a best-seller.
About 700 years ago a young trader from Italy took a long trip to Cathay. Cathay is known as China today. He went with his father and uncle, who had traveled there once before. They stayed in China for about two decades. The young man's name was Marco Polo. He was liked by the leader in China at the time.
He knew four languages and traveled around the kingdom as the leader. When Marco Polo returned to Italy, he dictated his story to a writer. He told of the Chinese postal system, paper money, and the use of coal as fuel.
James Cook (1728-1779) was the greatest Britain navigator. Cook enlisted in the Royal Navy in 1755. In 1768 he was promoted and sent to the Pacific where he surveyed Tahiti, New Zealand, and Australia. On his famous second expedition (1772-1775) he explored Antarctica. In 1776 he undertook his third and final voyage in which he explored
the West Coast of North America and tried to locate a passage between the Atlantic and Pacific oceans. On this voyage he discovered the Hawaiian Islands, and sailed up the coast of North America through the Bering Straits to the Arctic Ocean. On his return he was killed by Hawaiian islanders.
Can you identify these early navigational instruments seamen used? How do they work?
a bearing circlethe first instrument to measure the suns position and the suns shadow
The astrolabe measures the height and position of the sun. If you can measure this accurately, a sailor can tell how many degrees the boat is from the North Pole. From this he can tell where the boat is in the ocean.
The 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 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.
The 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 at 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.
Nautical charts are maps of the depth of the sea and the 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.
DiscussionHow 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.
Using nature Keeping alongside the coastlineUsing celestial bodies (north star; sun; clouds)Using wildlife (seaweed; birds)Using the weather (fog; winds)Using the sea
Using navigational instrumentsFinding longitudeFinding latitude (the bearing circle; the astrolabe; the quadrant; the sextant)
What do you think was the first and most important way of exploration then?Keeping alongside the coastline
Using celestial bodiesto plot the positionsto work out the latitudea special cloud formation indicates there is land close by
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.
Using the weatherTo help identify the position of a stream or river when they were close to land.To direct their sailing
Using the seacarry ships to their destinationtides and currents
Please complete the following blanks using the information of the text book.
1)Seamen explored the oceans by using _______ and navigational ___________. 2)Using nature navigators could keep alongside the _______, use such celestial bodies as North Star to _______ their positions, as the sun overhead to _______ by, as clouds over islands to indicate land close by. nature instruments coastline plot navigate
3)Wildlife, especially _______ could tell how far or close the ship was to land and _______ could be used to show the way. Fog could help identify the _______ of a stream or river and winds direct the sailing. Certain tides and currents could be used to carry ships to the _______. seaweed sea birds position destination
Using navigational instrumentsRead Page 2 and fill in the blanksThere were two methods to find longitude: 1. _______________________ 2._______________________measuring time and speedcompass and complicatedmathematical tables
Finding latitudeWrite down the working principles of the following instruments:Bearing circle:Astrolabe:Quadrant:Sextant:to compare the height of the sun with the position of the sun at middayto compare the position of the ship in relation to some stars or the suna more precise form of the astrolabe, to measure how high stars are above the horizon, and compare that measurement with previous measurementsan updated version of the quadrant and so it was more accurate, to measure the angle between two fixed points outside the ship
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.)
Please complete the following blanks using the information of the text book.
1.Navigational instruments helped the sailor to find ___________. They used the compass to calculate longitude and find the _______ for the ship to go. 2.The _____________ was the first instrument to measure the suns position. 3.The astrolabe could tell the position of the _______ in relation to the _______ and stars. longitude direction bearing circleship sun
4.The quadrant measured how high stars were above the _______ and the sextant was the updated version of the astrolabe and quadrant, measuring the _______ between two fixed objects outside the ship. It _______ to be the most accurate and reliable of the earlier _____________ instruments. horizon angle proved navigational
Replace the words underlined by ones of similar meanings from the reading passage.Seeing the dark clouds above him, George hurried for home. Sailing a boat alone far away from the shore made Floras parents worry about her safety.Clare, would you please put your bicycle next to the others in the shed?offshoreoverhead alongside
4. Why dont you plot a more simple route with the smallest number of stops? asked Mary.5. Setting out on a long journey by sea with unskilled sailors would be dangerous especially if there were no modern navigational instruments.simplifiedvoyageseamen
Comprehending1. Read the passage and answer the following questions.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 timeAB
2) Why are speed and time important in working 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.
3) 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 measure a ship's position.
1. What skills would you seek in your sailors?The sailors would need to be excellent navigators, able to cope with both hot and cold weather, experienced in sailing through very bad weather and able to co-operate in a team.
2. What problems would you anticipate for this journey?I would anticipate very hot weather (around the equator), cold weather (around Cape of Good Hope), very stormy seas (around the Cape), and problems with food and water, etc.
What would you do if you came across the following problems during your voyage?
wait till the 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
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.
What would you need for a weeks journey across the North Sea to England?shirt, trouserssoapblanketwaterproof bootsknife, scissorssea-sick tablets,
1. How do you think seamen found their way before modern accurate methods of navigation were invented? , ?
+do you think thinkbelieveguess, supposeimagineWhat do you suppose has happened to him?
?How do you think heat is different from temperature?What performance do you think we should give at the party?
When do you suppose they will be back?Where did they suggest we should go during the summer holidays?
I dont think he will come I thinkbelieveguesssuppose/ imagine, , ,
1.I don't think the boy is a student, __________?2.We think it is better for us to go home now _____________?
is he , isnt it
3.He believed Mary could do it well, __________? + think ( believe, suppose, consider ) + that, . TheyallthinkthatEnglish is very important, ? Hedidnt thinkthatthe news was true, ?didnt hedonttheydidhe
1.Ithinkthathehasdonehisbest, _______________?2.She doesn't think you are a good boy, ____________? 3.WethinkthatEnglish is very useful, _____________?4.He thinks you can do better, _____________ ?hasnt hedoes shedoesnt heisnt it
5.The boy must have got there yesterday, _________________?6.You used to go to school on foot, ______________________?didnt hedidnt you / usedn't you
2. work out to calculate an answer, amount, price, or value to think about sth. and manage to understand it to think carefully about how you are going to do sth. and plan a good way of doing it
eg. See if you can work out this bill . The plot is so complicated that itll take you a while to work it out.
I cant work out Geoff ; one day hes friendly; the next day he ignores me completely. I havent worked out whos going to look after the kids tonight.
1. We may well wonder how seamen explored the oceans before latitude and longitude made it possible to plot a ships position on a map. Page 1
These are excellent photographs and we may well use them in our magazine. You might well find that youll need more by the weekend.
+thinkfeelmakeconsider / find +it +n.adj.+ forof sb. to doitforof
I think it important for him to learn English wellI have made it clear that I object to the plan.
I feel it a great honor to come here to give a lecture.I have made it clear that I am disappointed at your performance.
We found it useless learning a theory without practice.
2. The voyages of travelers before the 17th century show that they were not at the mercy of the sea even though they did not have modern navigational aids.17
at the mercy ofwithout any protection against; helpless before They were lost at sea, ,
I dont like to be at the mercy of wind and weather.at the mercy of such a man.
have mercy on/ show mercy to
The terrorists showed no mercy to the hostages.
The mother left the dying baby in the hospital without mercy.
Its a mercy (that) (),()
Its a mercy the accident happened so near the hospital.
Its a mercy she wasnt seriously hurt.
3. minimum (min) adj. , n. , maximum (max) adj. , , n. , ,
40 The minimum requirements for the job are a degree and two years experience.
You must get a minimum of 40 questions right to pass the examination.
keep/reduce sth. to a m...