Unit13 Water and Ocean
TEACHING AIDS: Computer, pictures, flash card.
AIMS：To train the students to have love for the nature by knowing the properties of water and the present situation of water.
PROCEDURES：Properties of water (group work)----reading passages----answering questions
Preview: Two Tasks
Task One: Print the following picture and passage for the students to translate into Chinese as homework in the previous week.
Water is a polar molecule


Water's unique properties are largely a result of its simple composition and structure. As mentioned above, water is composed of two hydrogen atoms bound to one oxygen atom. As shown in your book, the two hydrogen atoms are smaller (the smallest atom there is, in fact) and they rest on both sides of the larger oxygen atom at an angle of 105? When the hydrogen atoms combine with oxygen, they each give away their single electron and form what is known as a covalent bond.
Because electrons are more attracted to the positively charged oxygen atom, the two hydrogens become slightlypositively charged (they give away their negative charge) and the oxygen atom becomes negatively charged. This separation between negative and positive charges creates what is known as a polar molecule, meaning a molecule that has an electricalcharge on its surface somewhere. Although the water molecule as a whole has no charge, the parts of it, the hydrogen wings and the oxygen body, do exhibit individual charges.
Task Two: Ask the students to form groups of four or five students to prepare the four experiments on Page17 .
A WARMING UP：Play a game: The students will have a class without English Books. So play a game with them. Let them guess what the teacher will have them to learn. Here are some sentences which the teacher may use to have the students follow:
T：I have something in my pocket. Can you guess what it is?
Ss: Is it …
T:
It's colorless;
It's tasteless;
It's odorless;
It feels wet;
It's distinctive in sound when dripping from a faucet or crashing as a wave;
It dissolves nearly everything;
It exists in three forms: liquid, solid, gas;
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.
Ss: It’s water!
T: Yes! (show a globe to the students.) What’s this?
Ss: It’s the earth.
T: What color is it?
Ss: It’s blue.
T: Why is it blue?
Ss: Because it’s covered by water.
T: Yes, because two thirds of the surface of the earth is covered by water. That’s why our earth is called the water planet. (show paragraph one)
Now how much do you know about water? In what ways can we use water?
Ss: …
The students will do the experiments they have prepared once again in group form. When they are doing the experiments, they will explain to the audience in plain English.
T: Ok. Let me show you more about water by some pictures. Look at the pictures. Then tell us in what ways we can use water.
Speaking：
Water can be used to make electricity.
Water can be used to water fields.
Water can be used to wash our food.
Water can be use for industry /transport/ entertainment.
Reading: Ask the students to read the passage for 10 minutes, then ask them to do the True or False exercise.
Qs:
1. Water is polar, water is a liquid at room temperature; water has a high freezing point. The density of water is 1,000 kilograms per cubic meter.
True.
False.
2. About three billion years ago, life on our planet began in the deep blue seas.
True.
False.
3. Ninety-nine percent of the living space on earth is in the oceans.
True.
False.
4. It is water that makes the ocean such a great place to live.
True.
False.
5. Water can break down neither solids nor gas
生词表: