2. Unit 13

3. Period 1 Reading

4. The Properties of Water

5. Find out as many words and phrases as possible about water properties in the text. polar salinity density high heat capacity ocean motion ------

6. 1.Water is a liquid at room temperature, and it has a relatively high freezing point. 2.The reason why water can dissolve most substances on earth is that water has high heat capacity. 3.Like all the other substances, water gets smaller (contract 缩小 ) when it freezes. 4.Pure water has a higher freezing point and lighter than salt water. 5.The salinity of the earth’s oceans is about 3.5%. 6.When water freezes, its density increases. 7.Other recourses such as oil, gas, gold etc is as precious as a drop of rain. Because water is polar gets expand decreases Nothing is as precious as ---

7. Find out some basic facts about life in the oceans

8. Basic facts about life in the oceans from the opening paragraph : Life on earth began in the oceans about three billion years ago; 99% of the living space on earth is in the oceans; There are about five million (known) species in the oceans; Life in the oceans ranges from tiny plankton to giant whales.

9. Life first appeared in the blue seas. Natural selection A diverse world

10. 99% of the living space on earth is in the oceans. Why? Because the chemical structure of water makes it an excellent medium (substance /surroundings) for life. How many species and how rich? Five million ranging from the tiniest plankton all the way up to giant sharks and whales.

11. Why ? Water is an excellent medium for life.Why ? Water is a liquid at room temperature and has a relatively high freezing point; All living creatures need food to survive, but on many occasions the nutrients become available to living things only when they are dissolved by water. Water is polar, it can break down both solids and gases. Why?

12. Water’s unique chemical structure Oxygen Atom Hydrogen Atom A polar molecule

13. We can get a lot of nutrients by drinking soup. Plants can pull water up their roots via a capillary( 毛细管 ) process. Can you give some other examples which are also resulted from water’s unique chemical structure?

14. The salinity of the earth’s oceans is about 3.5%. What does this mean? What does this mean? There are about thirty-five grammes of dissolved solids and gases in one kilogramme of water.

15. In winter water in some containers or small rivers often freezes while water in seas not? Can you explain why ? The salinity of sea water can affect the freezing point of water. Sea water has a lower freezing point, so even when the temperature of sea water falls below 0 ℃, sea water is still liquid.

16. What is density? Density is the relationship between _______ and _________ and is measured in kg/m3, reading ___________________. The density of water is ________ kg/m3. massvolume kilos per cubic meter 1,000

17. Does the heat capacity of water also make the ocean an excellent medium for life? Why? (a safe and comfortable habitat) The heat capacity of water is relatively _____. Water can _____ and _______a lot of heat without big _______ in temperature, ______ creating a ______environment. Most animals and plants are _________to large or sudden changes in _________,the water in the oceans also Keeps the temperature of the earth ______ by ________and ________heat. high absorbgive off changes thus stable temperature sensitive steadyabsorbinggiving off

18. What’s the function of ocean motion? Ocean motion helps move nutrients around and adds energy to the marine ecosystems. Different marine creatures live in different levels of the ocean. (Because of the foods they need, sunshine etc.)

19. what property of water can explain the following phenomena? The coastal areas are often neither too hot nor too cold. Ice floats on water. When the sea water in a container is evaporated ( 蒸发 ), there will be some salt left. Irrigate in winter can help raise the soil temperature. People swimming in the Dead Sea float; they can even read a paper while lying on their back in the water. Water’s high heat capacity Density Dissolvability High heat capacity Salinity and density

20. Your body floats on the surface of the Dead Sea

22. These figures show how much water there is in parts of our body! 60% 70% 82% 90%  Up to _____ of the human body is water.  The brain is composed of _____ water.  Blood is _____ water.  The lungs are nearly _____ water. 82% 60% 90% 70%

23. Water is being used for … Water is being used for … Electricit y Agricultur e Home use Industry Transport Entertainment

24. Water is a must to life. Without water, Without water, life would not exist.

25. 22 nd, March What should we do today and from today on to save water? The theme for this year “Water For Life”

26. Water is so important that we Should value every drop of it. Do it from now on! Do it every minute! Save water! Save life! Save the earth! For human beings! For coming generations! For the future ! Take action!

27. Try to think as many examples as possible to show that water is made use of to bring benefit to human beings. Try to think as many examples as possible to show that water is made use of to bring benefit to human beings. HomeworkHomework