Talk about the earth and the importance of water for life.

Animals and plants cannot live without water.

1.What is our earth made up of ?2.What do you think of the role water plays in our daily life ?3.Could you please give some examples ?

Our earth is mostly made up of waters.

tortoise

( )1.Based on Para. I, the author tells us that there are various species in the oceans, indicating that ____.

A. Water plays a great role for marine life. B. Ocean is a good place for life. C. There are many reasons for tiniest plankton and giants like sharks and whales D. Ocean is part of the earth( )2.The water in the ocean is always moving is that _____. A. The temperature of sea water is relatively high. B. Water’s density affect changes in salinity and temperature. C. Changes in salinity and temperature have effect on water’s

density. D. Waters in rivers always flow into the ocean.( )3.Generally speaking ,human beings are ______ to large or

suddenly changes in temperature. A. generous B. objective C. subjective D. sensitive

Reading ComprehensionA

C

D

Properties of WaterPara.1

chemical structure

Para.2

salinityPara.3

DensityPara.4

Heat Capacity

Para.5

Ocean motion

Para.6

How the text is organized.

chemical structure of waterPara.2

water molecule

two hydrogen atoms

one oxygen atom

The water molecule is made up of two hydrogen atoms and one oxygen atom.The chemical structure of water makes it an excellent medium for lifeand also makes it different from almost everything else on earth.

Key points:

salinityPara.3 sea water

dissolved solid and gases pure water

Key points:

The salinity of the earth’s oceans is about thirty-five parts per thousand.There are about 35 grammes of dissolved solidsand gases in one kilogramme of water.

Sea water consists of dissolved solid and gases as well as pure water.

= salt water

Compared with pure water, Salt water has a low freezing point and is heavy.

DensityPara.4

mass volumeDensity

key points:

Density is the relationship between mass and volume, measured in kilogrammes per cubic metre.The density of pure water is 1,000 kg/m3.

One cubic metre of water weighs one thousand kilogrammes.

Heat CapacityPara.5

the amount of energyit takes to raise the temperature of

a substance by one degree centigrade

water heatabsorb and give off

The ocean has a stable environment in that water can absorb and give off heat to keep both the temperaturesof the ocean and the earth steady.

relatively high

Heat Capacity

Ocean motionPara.6

water in the ocean always moving

changes in salinity and temperature

water’s densityaffect

It is very important to learn about the properties of water.

We must protect water and use it wisely.

Water is what makes life possible.

Find the following phrases according to the Chinese

Post-Post-reading reading

PHRASES

• 海洋性星球• 99%的生存空间• 海洋生物• 丰富多彩• 500万种生物• 使海洋成为优越的生活场所

1.an ocean planet

2.ninety-nine percent of

the living space

3.marine life

4.rich and varied

5.five million species

6.make the ocean such a

great place to live

PHRASES• 完美的生活环境• 水分子• 独特的性质• 由…构成• 构成一个极性微粒• 一极稍微偏正• 分解• 被其他生物所利用• 使得它不同• 相对较高的冰点

1.an excellent medium for life

2.the water molecule

3.unique properties

4.be made up of

5.form a polar molecule

6.a slightly positive end

7.break down

8.become available to other living

creatures

9.make it different

10.a relatively high freezing point

PHRASES

• 溶解的气体• 混合• 千分之 35

• 即使• 它的主要特征• 冰点

1. dissolved gases

2. mix with

3. thirty-five parts per thousand

4. even though

5. its main properties

6. freezing point

PHRASES

• 质量和体积的关系

• 以…测量

• 有较高的密度

• 海洋动植物

• 利用

1. the relationship between

mass and volume

2. be measured in

3. have a higher density

4. marine animals and plants

5. take advantage of

PHRASES• 热容量• 所需要的能量• 温度提高一度• 释放大量热量• 创造一个温度的环境• 对…敏感• 温度的突然改变• 使地球的温度保持稳定

1. heat capacity2. the amount of energy3. raise the temperature by

one degree centigrade4. give off a lot of heat5. create a stable environment6. be sensitive to7. sudden changes in

temperature8. keep the temperature of

the earth steady

PHRASES

• 使海洋生态系统增加能量

• 使营养物质移动

• 整个宇宙

• 使生命成为可能

• 了解水的性质

• 依靠

1. add energy to the marine

2. move nutrients around

3. the whole universe

4. make life possible

5. learn about the properties

of water

6. depend on

Post-Post-reading reading

Complete the chart below.

Property What is it? What is it good for?

Chemical

structure

Density

Heat

capacity

The water molecule is made up of two hydrogen atoms and one oxygen atom. The water molecule is polar--- it has a slightly negative and a slightly positive end

Because water is polar, it canbreak down nutrients quickly.The chemical structure of wateralso makes it different from most other substances: it is a liquid at room temperature and has a rela-tively high freezing point.

Density is the relationship between mass and volume

The density of water helps Small creatures float. Because thedensity of water decreases when it freezes, the oceans never freeze totally.

Heat capacity is the amount of energy it takes to raise the temperature of a substance one degree centigrade.

The heat capacity of water keeps the oceans at a steady temperature, which makes it a good place to live for creatures that are sensitive to Sudden changes in temperature. The water in the oceans also keeps the temperature of the earth steady.