Unit 13 The Water Planet教案

tip one
 if we are describing a process，we’d better explain each step in the order it happens. tell the readers about the causes and effects and use words like first, second, then, etc to show the order of the steps.
• first…
• second…
• third/ then…
• last…
tip two
    if we are writing about something that has several parts, we should describe each part and explain its function and structure.
   the following questions may help:
   what is it? how many parts is it made up of?
   what’s the structure of each part? how does it work?
homework
imagine that your science teacher ask you to explain one of the following questions:
why does an ice cube float?
what will happen to a piece of metal if you put it in water?
why do so many species live in estuaries?
why have so many cities been built by estuaries?
choose one of the questions and write a passage, using what you know about nature and science and what you have learned from this unit.
period 4 grammar and word study
teaching goals:
◆ to review modal verbs.
◆ to make students get more familiar with the modal and practise using them in different situations.
◆ to enable students to master some new words and expressions.
teaching procedures:
part one:  grammar — modal verbs
 revision
we have talked about the properties of water and we know that water can be used in many ways due to these properties. so please answer the following questions.
what are these properties of water?
can you give some more examples that show we can benefit from these properties of water?
according to the above discussion, we know that these properties of water are very important and help us a lot. just because of these properties of water, water can meet people’s needs of living on the earth. we can say that water is the “life food” of the earth. it is a necessity of human beings and all the other living things. however, have you ever imagined the following situations?
ii. presentation
without ocean motion, what would the earth be like?
(without ocean motion, the earth would…)
if the density of ice were larger than that of water, what would the seabed be like?
(if the density of ice were larger than that of water, the seabed would…)
suppose water had a much lower freezing point, what would the world be like?
(suppose water had a much lower freezing point, the world would…)
iii. try to list some modal verbs according to their functions.