高二 Unit13 教案（Period 2）

(Teacher gives students enough time to read the text and collects their information for the chart.)

Suggested answers:

Property

What is it?

What is it good for?

Chemical structure

Every water molecule is made up of two hydrogen atoms and one oxygen atom.

It is good for the living things in the ocean to absorb the nutrients easily.

Density

The density of pure water is 1 000 kg/m³,meaning that one cubic metre of water weighs one thousand kilogram.

It is good for marine organisms to take advantage of the density of water.

Heat capacity

Heat capacity is the amount of energy it takes to raise the temperature of a substance one degree centigrade.

It is good for the earth to keep the temperature steady.

T:Very good.What about the questions on the blackboard?

S₅:I think I can answer the first one.The answer is that the properties of water are chemical structure,salinity density,heat capacity and ocean motion.

S₆:In my opinion,the answer to the fourth question is that the ocean can be compared to a great place to live in.

T:Do you agree with them?

Ss:Yes.

T:What about other questions?

S₇:I think plankton,sharks and whales are examples of species in the ocean.

S₈:The answer to the second one is that the earth looks like an ocean planet.

T:You are quite right.Any volunteers?

S₉:Dear teacher.Can you tell us the meaning of the special air-conditioner—the ocean?

T:Maybe it means that there are some similarities between air-conditioner and the ocean.

S₉:Thank you.I got it.

T:Then,who can answer the question?

S₁₀:Because the ocean can keep the temperature of the earth steady,some students compare the ocean to a special air-conditioning.I think the ocean keeps the temperature of the earth steady by absorbing and releasing heat.

T:Well done.There is only one question left.Who wants to try?(Nobody answers the question.)

T:Do you think it is a question that the text can’t answer?

Ss:Yeah.We think so.

T:OK.Maybe you are right.But I want to know the reason why you think the passage can’t answer the third question.

Ss:Because there is not any information about the different parts of the ocean.

T:Then,are there any questions you would need to add to “cover” all the information in the text?