Talk about the earth and the importance of water for life. 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 ? tortoise Our earth is mostly made up of waters. Animals and plants cannot live without water.
Reading Comprehension A ( )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 C D
How the text is organized. Properties of Water Para.1 Heat Capacity Para.5 Ocean motion Para.6 chemical structure Para.2 salinity Para.3 Density Para.4
chemical structure of water Para.2 two hydrogen atoms water molecule one oxygen atom Key points: 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 life and also makes it different from almost everything else on earth.
salinity Para.3 sea water = salt water pure water dissolved solid and gases Key points: Sea water consists of dissolved solid and gases as well as pure water. The salinity of the earth’s oceans is about thirty-five parts per thousand. There are about 35 grammes of dissolved solids and gases in one kilogramme of water. Compared with pure water, Salt water has a low freezing point and is heavy.
Density Para.4 Density mass volume 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 Capacity Para.5 the amount of energy it takes to raise the temperature of a substance by one degree centigrade Heat Capacity relatively high water heat absorb and give off The ocean has a stable environment in that water can absorb and give off heat to keep both the temperatures of the ocean and the earth steady.
Ocean motion Para.6 always moving water in the ocean changes in salinity and temperature affect water’s density Water is what makes life possible. It is very important to learn about the properties of water. We must protect water and use it wisely.
Post-reading Find the following phrases according to the Chinese
PHRASES 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 • 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
PHRASES 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 • 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
PHRASES • 溶解的气体 • 混合 • 千分之35 • 即使 • 它的主要特征 • 冰点 • dissolved gases • mix with • thirty-five parts per thousand • even though • its main properties • 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 • the relationship between mass and volume • be measured in • have a higher density • marine animals and plants • take advantage of
PHRASES • heat capacity • the amount of energy • raise the temperature by one degree centigrade • give off a lot of heat • create a stable environment • be sensitive to • sudden changes in temperature • keep the temperature of the earth steady • 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
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 • add energy to the marine • move nutrients around • the whole universe • make life possible • learn about the properties of water • depend on
Post-reading Complete the chart below.
Because water is polar, it can break down nutrients quickly. The chemical structure of water also makes it different from most other substances: it is a liquid at room temperature and has a rela- tively high freezing point. 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 The density of water helps Small creatures float. Because the density of water decreases when it freezes, the oceans never freeze totally. Density is the relationship between mass and volume 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. Heat capacity is the amount of energy it takes to raise the temperature of a substance one degree centigrade.