【正文】 and sources, thus cleaning our water. 4. Why are estuaries more sensitive to pollution than other areas? Because estuaries act as filters(過濾器 ), many pollutants end up in them. 5. Why are estuaries important to human beings? (1)Estuaries provide both recreation and education for human beings. People can fish, swim and have fun on the beach. Scientists and students have endless opportunities to study a variety of life in the habitat. (2)Estuaries also contribute to the economy through tourism Finding Topic Sentences Paragraph 1. As the oceans are the source of life on earth, the estuaries are our pla\39。 All living creatures need food to survive, but on many occasions the nutrients bee available to living things only when they are dissolved by water. Water‘s unique chemical structure Hydrogen Atom+ Oxygen Atom= A polar molecule Can you give some other examples which are also resulted from water‘s unique chemical structure? We can get a lot of nutrients by drinking soup. Plants can pull water up their roots via a capillary(毛細(xì)管 ) process. The salinity of the earth‘s oceans is about %. What does this mean? There are about thirtyfive grams of dissolved solids and gases in one kilo of water. In winter water in some containers or small rivers often freezes while that in seas not? Can you explain it? The salinity of sea water can affect the freezing point of water. Sea water has a lower a freezing point, so even when the temperature of sea water falls below 0℃ , sea water is still liquid. What is density? Density is the relationship between mass and volume and is measured in kg/m3, reading kilos per cubic meter The density of water is 1,000 kg/m3 Scanning Structure of the passage THE PROPERTIES OF WATER: CHEMICAL STRUCTURE, SALINITY, OCEAN MOTION, HEAT CAPACITY, DENSITY Main idea The passage mainly tells us it is water that makes the ocean so important to all the living things in the world. Finding Topic Sentences Paragraph 1 Learning about the properties of water helps us understand life on our pla. Paragraph2 The chemical structure of water makes it an excellent medium for life. Paragraph 3 The salinity of the earth\39。 poverty he Great Depression Unemployment The Civil Rights movement Sacrifices Give some examples of hope and success of the South people of Atlanta struggled to rebuild the city and create a new South. ‘s AfricanAmerican munity grew and black businesses became more successful disappeared and Atlanta was a successful city proud of its cultural diversity bees a place where hope and faith have replaced fear and doubt. Discussion Why is Atlanta in many ways a typicalsouthern city? INTEGRATING SKILLS THE BISON ON THE PLAINS OF AMERICA I D Card Name: bison Order: artiodactyl (偶蹄。s density, the water in the ocean is always moving. Comprehension Paragraph 1. marine life: (definition based on the text) Niynine percent of the living space on earth is in the oceans. incredibly: unbelievably doubtfully extremely questionably Life in the oceans ranges from the tiniest plankton all the way up to giants like sharks and whales. (paraphrase Paragraph 2. H2O:2 Hydrogen Atoms + 1 Oxygen Atom = 1 H2O Molecule medium: average channel means condition polar: +√ –√ ↑ ↓ positive end: +√ – ↑ ↓ negative end: + –√ ↑ ↓ Normal state of water: solid liquid√ gas Why is the chemical structure of water important? 1. Because water is polar, it can break down both solids and gases. nutrients in whatever falls into the ocean quickly bee available to other living creatures. 3. The chemical structure of water also makes it different from almost everything else on earth. The nutrients in whatever falls into the ocean quickly bee available to other living creatures. (paraphrase Paragraph 3. sea water (salt water) = dissolved gases+ dissolved solids+pure water salinity of sea water affects: weight and freezing point salinity of sea water: 35‰ √ 35% Paragraph 4. Factors of density: mass and volume Unit of density: kg/m3 = kilogrammes per cubic metre Density of pure water: 1,000 kg/m3= one cubic metre of water weighs one thousand kilogrammes When water freezes, its density decreases. If it did not, the oceans would be frozen solid. (paraphrase) Paragraph 5. Heat capacity: water temperature substanc energy√ Opposite word/phrase of absorb: give off √ change create Paragraph 6. How does the water in the ocean move? Dense water sinks and less dense water is pushed to the surface. Paragraph 7. Main idea: significance of water to nature Water, which seems so simple and mon, is what makes life possible. Of all the resources on earth oil, gas, gold and so on nothing is as precious as a drop of rain. (paraphrase) Integrating Skills Skimming Find the definition of an estuary An estuary is the body of water where a river meets the ocean. Salt water from the ocean and fresh water from the river mix together in an estuary. This mixing of fresh and salt water creates a unique environment filled with life of all kinds－ a zone between the land and sea. What kinds of function of estuaries have been mentioned in the passage? Great places for nature‘s young animals clean our water by absorbing nutrients and pollutants from water ing from inland sources。s oceans is about thirtyfive parts per thousand, meaning that there are about thirtyfive grammes of dissolved solids and gases in one kilogramme of water. Paragraph 4 The density of pure water is 1,000 kg/m3, meaning that one cubic metre of water weighs one thousand kilogrammes. Paragraph 5 Heat capacity is the amount of energy it takes to raise the temperature of a substance by one degree centigrade. Paragraph 6 Since changes in salinity and temperature affect water\