冀教版八年級(jí)下lesson 25 教學(xué)課件

1、Lesson 25: Lets Do an Experiment!Look into scienceUnit 4 New wordsThink about ittext Lets do itLesson 25:Lets Do an ExperimentLesson 25:Lets Do an Experiment!New words:scienceexperimenttheoryfilljarupsideproveobservemethodscientific What are they doing?Do you usually do any experiments in your physi

2、cs lesson?Do you like to do experiments?What will happen?The floor will get wet.The floor wont get wet.What about you?DannyBrianOne Experiment, Two TheoriesA “theory” is an idea. A theory predicts what will happen. An experiment shows what happens.Brian: Did you read about this experiment, Danny? I

3、fill a jar with water. I cover the top with a piece of cardboard. Then, I turn the jar upside down.Jenny: Guess what will happen!Danny: Im not sure. I think the floor will get wet. Maybe you should do this experiment outside, Brian!Brian: No, we can do it inside. Im sure the floor wont get wet.Danny

4、: Why not? The cardboard cant keep the water in the jar!Jenny: Lets do the experiment and see what happens. Brian has one theory, and Danny has another. We can prove whos right.Brian: Great! Well do the experiment and observe what will happen.1 fill with coverwith2 turn upside down3 be sure.4 observ

5、eMain Sentences 1. I fill a jar with water. 我用水我用水把瓶子裝滿。把瓶子裝滿。 fill with用用裝滿裝滿 He has filled his case with many books. 他已經(jīng)把書裝滿了箱子。他已經(jīng)把書裝滿了箱子。 coverwith 用用蓋住蓋住 I cover the top with a piece of cardboardRight side upupside down2. I turn the jar upside down. 我把廣口瓶倒置。我把廣口瓶倒置。upside down 的意思是的意思是“向下翻轉(zhuǎn)過向下翻

6、轉(zhuǎn)過來來”. You hold the book upside down. 你把書拿倒了。你把書拿倒了。right side up 是是“正面朝上正面朝上”的意思的意思be sure +that 從句表示從句表示“認(rèn)為認(rèn)為一定一定” 而而be not sure 表示不確定表示不確定.e.g. Im sure she will come here. 我確我確信她會(huì)來。信她會(huì)來。 Im not sure when hell come here. 我我不能肯定什么時(shí)候來這兒。不能肯定什么時(shí)候來這兒。3. Im sure the floor wont get wet. 我確信地板不會(huì)濕。我確信地板不會(huì)

7、濕。4. Well do the experiment and observed what will happen.我們將做這個(gè)實(shí)驗(yàn)并觀察會(huì)發(fā)生什么情況。我們將做這個(gè)實(shí)驗(yàn)并觀察會(huì)發(fā)生什么情況。 observed 動(dòng)詞動(dòng)詞, “觀察觀察”。 observe sb. do/ doing sth. 如：如： I observed her dance.When I passed by the grass, I observed himWalking. Lets do an interesting experiment. First, I _ a jar _a desk, _it _ water, th

8、en _the top _ a piece of cardboard. When I _the jar _ _, can you guess what will happen? putonfillwithcoverwithturnupsidedownWork in groups and think of this experiment .Discuss it and write down how we did it.Step 1 Preparation: Make a list of the materials and tools that we were used in the experi

9、ment. Step 2 Theories: Write down two different theories. 1. The floor will get wet. 2. The floor wont get wet. Water,a jar , a piece of cardboard.Step 3 Main steps:Write down the steps of doing the experiment1. Fill a jar with water.2. Cover the top with a piece of cardboard.3. Turn the jar upside

10、down. Observe carefully What will happen?Observe carefully and you can get the result:nStep 4 Result: n Write down the result of the experiment. nWOW!n The force of air will keep the water inn the jar.n n Are you right?1.Fill the jar with water2. Cover the top with a piece of cardboard.3. Put your h

11、and on the cardboard .And turn over the jar carefully. 4.Move your hand away quickly. 5.The cardboard will hold the water up.How to do this experiment 1. Whats the meaning of the word “theory”? A “theory” is an idea. A theory predicts what will happen. 2.Whats the meaning of the word “experiment”? A

12、n “experiment” shows what happens. Answer the questions 3.What does Brian do about the experiment at first ? He read about the experiment. He filled the jar with water,covered the top with a piece of cardboard, and then he turned it upside down. Listen again and answer more questions 4.Why does Dann

13、y want to do the experiment outside? Danny is not sure whether the floor will get wet? Listen again and answer more questions 5.Will Brian do the experiment inside? Yes. He is sure the floor wont get wet.6.What does Jenny say? Lets do the experiment and see what happens.Listen again and answer more

14、questionsHow to do this experimentxperientheoryrovepsidebserveExerciseFill in the blanks with the right words:Danny: What are you doing, Jenny?Jenny: I am doing an experiment.Danny: An experiment? What is it about?Jenny: A theory about air force (大氣壓力）大氣壓力）. I a jar water. I the jar a piece of cardboard. Then I the jar .Can you guess what .Danny: Im sure that the floor will .Jenny: No, I dont think so.Danny: Why? The cardboard cant keep the water in the ja