1、Properties of water,Unit 13,Reading,drink,Wash clothes,irrigation,transport,Fast reading,The main idea of each paragraph,Para1Para2Para3Para4,Properties of water make ocean a place to live.,The chemical structure of water makes it an excellent medium for life.,The salinity of sea water or salt water
2、.,The density of pure water and sea water,Para5 Para6 Para7,The main idea of each paragraph,Heat capacity & its importance to life,How ocean motion works,How important water means to life,Careful Reading,Life in the oceans,Life on earth began in oceans _ years ago. _of the living space on earth is i
3、n the oceans.therere_ in the oceanslife in the oceans ranges from the _ _to_.,three billion,five million species,99,tiniest,plankton,giant whales,Chemical structure,The water molecule is made up of two_ atoms and one_atom. Because water is _, it can _ solids and gases.,hydrogen,oxygen,polar,break do
4、wn,Salinity,1.How is the salinity of water formed?,Dissolved gases and solids mix with pure water.,2. How much is the salinity of the oceans?,About thirty five parts per thousand.,3.what does salinity of sea water affect?,It affects its weigh and freezing point.,Density,1.Density consists of mass an
5、d volume.( ) 2.The density of pure water is 2000 kg/m3( ) 3.Oil has a density lower than 1000 kg/m3,so it will float on water. ( ) 4.The density of water helps marine animalsand plants float.( ),T,F,T,T,Heat capacity,It is the amount of energy it takes to raise temperature of a substance one degree
6、centigrade.,It creates a stable environment for life in the ocean, and also keeps the temperature of the earth steady.,Ocean motion,1. Why is the water in the ocean moving?,Since changes in salinity and temperature affect waters density.,2. How does ocean motion work?,More dense water sinks and pushes less dense water to the surface.,3.why is water important to all living things?,It makes life possible . Our future relies on it.,What should we do to protect water from being polluted?,.,Discussion,Thank you!,
