space有生命的地方.ppt

1、Guess the riddle:Whats this?,It is very important to all the animals and plants.Its also important to human beings. Its a liquid at room temperature. It is tasteless, colorless and odorless. Every day you keep in touch with it.You cant live without it. (A thing),water,properties,What properties or c

2、haracteristics do you know about water?,colorless,tasteless,odorless,gas (steam),liquid,solid,salt water,fresh water,Where can we find water?,river,lake,ocean(sea),snow,waterfall,ice,stream,rain,water,Well,pool,water pollution,Without water, what would happen?,Without water, life would not exist. Wa

3、ter is a must to life.,22nd, March,World Day for Water is established on 22 December 1992. It is to remind everybody that we should try efforts to provide clean drinking water and know that the water problems are serious and solutions can help make the difference.,Theme:,Unit 13 The water planet,Why

4、 do we call it an ocean planet?,Oceans: _,99,Reading The properties of water,Common sense,How much do you know about water?,1. What state is water in at room temperature? A.liquid B.solid C. gas 2. The chemical structure of water is_ A. two hydrogen and one oxygen atom B. two oxygen atoms and one hy

5、drogen atom 3. The water molecule is polar,that is ,it has_ A. two negative and one positive end B. one negative and two positive end C. one negative and one positive end,4.If you pour water and vegetable oil into one glass,what happens? A.Oil floats on the water. B. Water floats on the oil. C.They

6、mix together. 5.Will chalk be dissolved if you put it into water? A. Yes B. No 6. Does the sea freeze? A. Yes B. No,7. Whats heavier,sea water or pure water? A. Sea water B. Pure water 8. Put an ice cube in a glass of pure water,what happens? A. It floats in the water. B. It sinks. 9. Put an ice cub

7、e in a glass of salt water, what happens? A. It floats on the water. B. It sinks.,the body of the text,1 minute to skim the passage and fill in the chart below. You do not need to read the whole text.,The properties of water,chemical structure,salinity,density,heat capacity,ocean motion,The text can

8、 be divided into three parts,Part one : (para 1) Part two : (para 2 para 6 ) Part three : (para 7 ),Find out some basic facts about life in the oceans,Part one: ( para1 ),Basic facts about life in the oceans from the opening paragraph :,Life on earth began in the oceans about years ago; of the livin

9、g space有生命的地方 on earth is in the oceans; There are about species 物种in the oceans; Life in the oceans ranges from在范围内变化,three billion30亿年,99%,five million,tiny plankton to giant .,Ocean is a great place to live. (main idea of para1),The properties of water,chemical structure,salinity,density,heat cap

10、acity,ocean motion,Part two : (para 2 para 6 ),What is waters unique chemical structure?,Oxygen Atom,Hydrogen Atom,A polar molecule,Chemical structure,Normal state of water: solid liquid gas,negative end: + ,positive end: + ,polar: + ,medium: average channel means condition,. H2O:2_ + 1_ = 1_,Hydrog

11、en Atoms,Oxygen Atom,H2O Molecule,Chemical structure,Chemical structure,Influence:,1. Because water is polar, it can break down both solids and gases. 2.The nutrients in whatever falls into the ocean quickly become available to other living creatures. 3. The chemical structure of water also makes it

12、 different from,sea water (salt water) = _+ _+_ salinity of sea water: 35 35% salinity of sea water affects: _and_,dissolved gases,dissolved solids,pure water,weight,freezing point,Salinity,/,heavier than pure water,lower than pure water,Factors of density: _and _ Unit of density: _ = _ Density of p

13、ure water: _= _,mass,volume,kg/m3,kilogrammes per cubic metre,1,000 kg/m3,one cubic metre of water weighs one thousand kilogrammes,Density,Influence:,Make the marine animals float around the sea.,The change of density when water freezes:,Its density decreases.,Heat capacity,Heat capacity: water temp

14、erature,substance energy,The heat capacity of water:,Relatively high,-absorb and give off a lot of heat without big changes in temperature.,Influence:,Create a stable environment.,Ocean motion,Ocean motion: Influence:,dense water,Less dense water,Add the energy to the marine ecosystems and moves nutrients around,It is always moving.,Part three :,Significance of water to nature,nothing is as precious as a drop of rain,Do not let your tear be the last drop of water in the world!,Talking : How to protect water ?,Show one s opinion: I think In one s opinion Perhaps is more important Maybe it wou