高二下英语Unit 13 The Properties of Water教案.docx
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高二下英语Unit13ThePropertiesofWater教案
高二下英语：
Unit13ThePropertiesofWater教案
Unit 13 The Properties of Water Teaching Goals
1. Talk about water and the ocean.
2. Practice communicative skills.
3. Review Modal Verbs.
4. Write an explanation paragraph.
The First Period
Teaching Aims:
1. Learn and master the new words and the useful expressions of this part.
2. Learn something about water by doing experiment.
3 Do some listening.
4. Improve the students’ speaking ability by talking.
Teaching Important Points:
1. Make the students be free to talk about water.
2. Improve the students’ listening ability by listening.
Teaching Difficult Points:
1. How to finish the task of speaking.
2. How to improve the students’ listening ability.
Teaching Methods:
1. Listening-and-answering activity to help the students go through with the listening material.
2. Individual, pair or group work to make every student work in class.
Teaching Aids:
1. the multimedia
2. the blackboard
3. an empty glass, a bottle of water and a bottle of vegetable oil
Teaching Procedures:
Step 1 Greetings and Lead-in
Read a short poem and guess its name:
A letter from _______. （Water）
Dear User,
Shame to you all, the Ignorant,
I am your life
But you seem not to value me
Give me all the respect
For in me is eternal life
If you continue abusing me
Surely, all forms of life will wither away
Have you ever imagined,
Life without me?
I tell you, it will be unbearable
Think twice
For every drop counts...
Qs:
1） What does “Dear user” here refer to?
2） What does it talk to its users?
3） On which planet does it exist?
－On the earth, which is also called the water planet.
4） Do you know why it is called “The water planet”?
－Because about three quarters of the earth is covered by water.
Step2:
Pair work:
Collect as many words as possible related to water.
Qs:
How much do you know about water?
Is all water fresh or salty?
water
Step3:
Talk about the properties of water.
1. Pair work
T:
Water is around us and inside us. We can’t go without water.
Qs:
Why is water so important to living things?
Can you point out some of its properties or characteristics?
Suggested vocabulary:
It’s colorless, tasteless, odorless and universal dissolvent.
It feels wet;
It exists in three forms:
liquid, solid, gas, and is cycled through the water cycle;
It can absorb a large amount of heat;
It sticks together into beads or drops;
It’s part of every living organism on the planet; etc.
Properties
2. Group work
Learn more about water’s properties by doing some simple experiments and learn to describe an experiment.
What property of water does each of the four experiments illustrate?
What causes this phenomenon?
What’s this phenomenon related to?
① Experiment 1 shows how air pressure causes a piece of thick paper to cling to an upturned glass of water. ② Experiment 2 illustrates how substances with different density behave when placed in the same container. ③ Experiment 3 is an example of how water dissolves substances and objects. ④ Experiment 4 illustrates some of the differences between salt water and fresh water. 3. T:
What other properties of water do you know about?
What causes the following phenomena?
Can you explain?
①We can get a lot of nutrients by drinking water and having soup.
②Wood floats on water while iron sinks.
③The coastal areas are often neither too hot nor too cold.
④Why can some living things live at the bottom of the ocean where there is no sunshine?
（If these questions are too difficult） Try asking questions about the properties of water and then give answers to them.
Step5:
Homework
1． Read the text carefully and find out the detailed information about water properties.
2． Think as many examples as possible to illustrate water properties.
The Second Period
Teaching Aims:
1. Learn and master the some new words and phrases.
2. Improve the students’ reading ability.
3. Enable the students to realize that it is important to protect the water on our planet.
Teaching Important Points:
1. Improve the students’ reading ability.
2. Master the following phrases:
all the way, that is, mix with, take advantage of, manage to do
Teaching Difficult Point:
How do we make the students understand the reading passage better.
Teaching Methods:
1. Discussion before reading to make the students interested in what they will learn.
2. Fast reading to get a general idea of the text.
3. Discussion after reading to make students understand what they’ve learned better.
4. Careful reading to get the detailed information in the text.
Teaching Aids:
1. the multimedia
2. the blackboard
Teaching Procedures:
Step 1 Greetings
Step 2 Revision and Lead-in
Ask someone to illustrate water properties.
Step3:
Pre-reading
Look at the titles in the text below. Do not read the whole text. Pick out the subject of each paragraph. Use the structures below to make six questions related to the subjects.
What is/ are ________?
What does _________ look like?
What are different parts of ______?
What can ________ be compared to?
How does _______ work?
What are some examples of ________?
Skim to find the words and phrases which describe the properties of water in the reading text.
Scan to Find out some basic facts about life in the oceans.
Life on earth began in the oceans about three billion years ago;
99% of the living space on earth is in the oceans;
There are about five million （known） species in the oceans;
Life in the oceans ranges from tiny plankton to giant whales.
T:
Yesterday you were required to ask more questions about water’s properties and find out the detailed information about water properties as well. So now let’s have a little quiz about the properties of water.
True of false questions:
1） Water is a liquid at room temperature, and it has a relatively high freezing point.
2） The reason why water can dissolve most substances on earth is that water has high heat capacity.
3） Like all the other substances, water gets smaller （contract） when it freezes.
4） Pure water has a higher freezing point and lighter than salt water.
5） The salinity of the earth’s oceans is about %.
6） When water freezes, its density increases.
7） Other recourses such as oil, gas, gold etc is as precious as a drop of rain.
（TFFTT FF）
Step4. While-reading
As we all know, Charles Darwin is famous for his “The Origin of Species”. （According to his theory of evolution）
Qs:
1） Was there any life on the earth billions of years ago?
2） If any, what was the original life like at that time?
3） Where did it live?
－In the deep blue seas.
4） How does the world take its shape, which is quite different from what it used to be, especially those various organisms?
－Billions of years’ natural selection.
2．It is said that 99% of the living space on earth is in the oceans.
Qs:
1） What does this fact result in?
－Marine life is incredibly rich and varied.
2） Can you give some specific numbers or examples?
－There are about five million species in the oceans. They range from the tiniest plants all the way up to giants （ sharks and whales）.
3） What does this fact imply?
Do you agree?
－Water is an excellent medium for life.
4） Why do you agree that water is an excellent medium for life?
（Based on common knowledge）
Ø Water is a liquid at room temperature and has a relatively high freezing point;
Ø All living creatures need food to survive, but on many occasions the nutrients become available to living things only when they are dissolved by water.
3．So we know that one of water’s properties is its dissolvability（溶解性）.
Qs:
1） Do you know what gives water such a unique property?
－The chemical structure of water.
2） What does the water molecule look like?
－A water molecule consists of two hydrogen atoms and one oxygen atom. The two hydrogen atoms are bonded to one oxygen atom to form a ’V’ shape. The two hydrogen atoms form a polar molecule, that is, one with a slightly positive end and one with a slightly negative end.
3） Can you give some other examples which are also resulted from water’s unique chemical structure?
－Plants can pull water up their roots via a capillary（毛细管） process;
－We can get a lot of nutrients by drinking soup.
That’s water’s another property－dissolvability.
4. Since water is such a universal solvent, it can dissolve just about anything including many gases and solids. As a result, there is sea water.
Qs:
1） Do you know the salinity of the earth’s oceans?
－about %.
2） What does it mean?
3） Have you ever noticed such a phenomenon that 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.
5. However, no matter whether it is sea water or pure water, “wood floats on water while iron sinks” always works. How do you explain that?
What property of water is this?
－If a substance has a lower density than water does, it will float on water; Otherwise, it will sink.
Qs:
1） What is density?
And what’s the density of pure water?
－Density is the relationship between mass and volume and is measured in kilos per cubic meter （kg/m3）. The density of water is 1,000kg/m3.
2） Does it also go for the phenomenon that Ice looks larger than water of equal m
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