Warming up、Pre-reading、Reading、Comprehending优秀教学实录

姓名__________ 班级____________

M9 U2 READING 1 —— SAILING THE OCEANS We may well wonder how seamen explored the oceans before latitude and longitude made _______ possible to _________ (A. picture

B. plot

C. draw

D. sign) a ship’s position on a map. The voyages of travellers before the 17th century show that they were not _______ the mercy of the sea even though they did not have modern navigational aids. So how did they navigate so well? Read these pages from an encyclopedia. Page 1: Using nature to help

Keeping alongside the coastline This seems to have been the first and most useful form of exploration which carried the minimum amount of risk. Using celestial bodies ●

North Star At the North Pole the North Star is at its highest position in the sky, but at the equator it is along the horizon. So ________________ (accomplish) navigators were able to use it to plot their positions. ●

Sun ________ a clear day especially during the summer the sailors could use the sun overhead at midday to navigate by. They can use the __________ (high) of the sun to work out their latitude. Using wildlife ●

Seaweed Sailors often saw seaweed in the sea and could tell _______ the colour and smell how long it had been there.

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Birds Sea birds could be used to show the way to land when it was nowhere to be seen. In the evening nesting birds return to land and their nests. So seamen could follow the birds to land even if they were offshore and in the open sea. Using the weather ●

Clouds Sea captains observed the clouds over islands. There is a special cloud formation which indicates there is land close by. ●

Fog Fog gathers at sea as well as over streams or rivers. Seamen used it to help identify the position of a stream or river when they were close to land. ●

Winds Wise seamen used the winds to ____________ (A. direct

B. fuel

C. plan

D. secure)

their sailing.

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So the Vikings would observe the winds before and during their outward or return journeys. Using the sea Certain tides and currents could be used by skillful sailors to carry ships to their destination.

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These skills helped sailors explore the seas and discover new lands. They increased their ability to navigate new seas when they used instruments. Page 2: Using navigational instruments to help Finding longitude There was no secure method of measuring longitude ___________ the 17th century when the British solved this theoretical problem. Nobody knew that the earth moved westwards 15 degrees every hour, but sailors did know an approximate method of calculating longitude _________ (use) speed and time.

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The rope was tied to a log which was then thrown into the sea. As the ship advanced through the water the knots were counted as they passed through a seaman’s hands. The number of knots that were counted during a fixed period of time gave the speed of the ship in nautical miles per hour.

Later, when seamen began to use the compass in the 12th century they could calculate longitude using complicated mathematical tables. The compass has a special magnetic pointer which always indicates the North Pole, so it is used to help find the direction that the ship needs to go.

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Finding latitude ●

The Bearing Circle It was the first instrument to measure the sun’s position. A seaman would measure the sun’s shadow and compare it with the height of the sun at midday. Then he could tell ______________ he was sailing on his correct rather than a random course.

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The Astrolabe The astrolabe, quadrant and sextant are all connected. They are developments of one another. The earliest, the astrolabe, was a special all-in-one tool for telling the position of the ship in relation to the sun and various stars which covered the whole sky. This gave the seamen the local time and allowed them to find their latitude at sea.

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The Quadrant This was a more precise and ______________ (simplify) version of the astrolabe. It measured how high stars were above the horizon using a quarter circle rather than the full circle of the astrolabe. It was easier to handle because it was more portable. Its shortcoming was that it still used the moving ship as one of the fixed points of reference. As the ship rose and plunged in the waves, it was extremely difficult to be accurate with any reading. ●

The sextant The sextant was the updated version of the astrolabe and quadrant which reduced the tendency to make mistakes. It ______________ (prove) to be the most accurate and reliable of these early navigational instruments. It works by measuring the angle between two fixed objects outside the ship using two mirrors. This made the calculations more precise and easier to do.

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I. Fill the blanks. II. Match the following choices with the numbers in the passage. A. In this way the ship could set a straight course even in the middle of the ocean. B. If it was fresh and smelled strongly, then the ship was close to land. C. However, it was awkward to use as one of the points of reference was the moving ship itself. D. They could accelerate the speed, but they could also be dangerous. E. An early method of measuring speed involved throwing a knotted rope tied to a log over the side of the ship.

IV. What would you do if you came across the following problems during your voyage? Read the chart below and fill in your plans of action to deal with them. What would you do if:

Plan of action

you were offshore but you needed more food

and water. you knew your latitude but didn’t know your

longitude. you wanted to keep a straight course.

you were blown off course.

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VI. Complete the following paragraph with the words below.

VII. Which words, phrases and sentences impress you most? _______________________

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