Warming up、Pre-reading、Reading、Comprehending多媒体教案及点评

Unit 2 Sailing the oceans The First Period Reading Teaching Aims:

a. Learn and master the key words and expressions

voyage mercy minimum nowhere pole overhead offshore accelerate outward longitude latitude precise simplify portable shortcoming updated tendency reliable at the mercy of, even though, work out, be used to, in relation to, aim to , …

b. Train the students’ reading ability. Let the students have some knowledge of early navigational methods. Explain how seamen explored the oceans and what kind of navigational instruments were used to sailors before the 17th century when they were navigating the open seas without seeing the land. Teaching Difficult Points: a. How to help the students understand the reading passage better. b. How to improve the students’ reading ability.

Teaching procedures & ways

Step1 Greetings Greet the whole class as usual.

Step2 Warming up

What is the difference between a navigator and an explorer? Step3 Pre-reading Show the students some pictures to see if they can identify the early navigational instruments seamen used and explain how they used. Step 4 Reading Fast reading Decide whether the following statements are true (T) or false (F). 1. An early method of calculating longitude was to use a knotted rope tied to a log.

T

2. The astrolabe was the first instrument to measure the sun’s position. F

3. The quadrant was more precise and simplified than the astrolabe, but still had its shortcoming.

T

4.Up till now, the most accurate and reliable navigational instrument is the sextant.

F

5. The astrolabe, quadrant and sextant are different kinds of navigational

instruments and they have nothing to do with each other.

F

Careful reading.

Read the passage and answer the following questions. 1. What’s the main idea of the passage?

The reading passage explains how seamen explored the oceans and what kind of navigational instruments were used to sailors before the seventeenth century 2. What is the use of a bearing circle,

astrolabe, quadrant or sextant? (

B

)

What is the use of a compass?

(

A

)

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 time 3. 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 or change in your position in relation to the stars. 4. Why is the position 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 ship's position. Step 5 Discussion Suppose you were a sea captain aiming to sail round Africa. Discuss in groups:

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 cooperate in a team

Step 6 Summary Read the passage again and use the information to analyze the navigational skills. Using nature 1. To find the ship’s position at sea a sailor used the North Star and the sun. 2. A sailor knew that land was nearby if he saw fresh seaweed, nesting birds returning home in the evening or fog 3. Sailors used sea currents or tides and winds to increase their speed.

Using instruments

4. There were two methods to find longitude:

1) measuring time and speed

2)

compass and complicated mathematical tables

5 Write down the working principles of the following instruments: Bearing circle: to compare the height of the sun now with the position of the sun at midday.

Astrolabe:

to compare the position of the ship in relation to some stars or the sun

Quadrant: 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 position)

Sextant:

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 ship's position).

Step7 Consolidation

We may want to know (1)____seamen explored the oceans(2)_______ latitude appeared. (3)_______they didn’t have the modern navigational help, seamen could still control the sea by using some skills to explore seas and discover the new lands. (4)______ (use) nature is the first and most useful form of (5)_________(explore), such as using celestial bodies, using wildlife, using the weather, and using the sea. Because of these skill, sailors increased the ability(6)__

navigate new seas whaen they used instruments, (7)______

(include) longitude and latitude. 1. how 2. before 3. though 4. using 5. exploration

6. to 7. including Step8

Homework 1. Review this passage. 2. Preview Learning about

language.