冀教版英语九年级Lesson 25 Let’s Do an Experiment !（课件PPT）

Unit 5 Look into Science 冀教版 英语九年级全一册Lesson 25 Let′s Do an Experiment ! Curriculum words: pour, correct, scientific, method, raincoat, force, pressure Useful expressions: I cover the top with a piece of cardboard and hold it there. I am so sure of my theory that Brian can do the experiment over your head and I know you won′t get wet.Functions： Master the new words: experiment, jar, upside, pour, correct, scientific, method, raincoat, force, pressure, conclude Grammar： be动词(am/is/are)＋动词的过去分词Sentences： The force of the air keeps the water in the jar. It is strong enough to hold the water.Do you like doing experiments ? Why?THINK ABOUT ITWhat kinds of experiments have you done in science class?If you hold a jar that is filled with water upside down，what will happen?课文呈现 Danny，Jenny and Brian are in the lab.Brian：Let′s do an experiment. I fill a jar with water. I cover the top with a piece of cardboard and hold it there. Then I turn the jar upside down and take my hand off the cardboard. Can you guess what will happen?Danny：I think the floor will get wet. We should do this experiment outside，Brian.Jenny：I think the cardboard will hold the water.Danny：I don′t think so.Jenny：You think the water will pour out，Danny. I think the water will stay in the jar. Let′s test which theory is correct.Brian：Good idea，Jenny. That′s called the scientific method.Jenny：I am so sure of my theory that Brian can do the experiment over your head and I know you won′t get wet.Danny：Well，let′s try it!Brian：Are you ready，Danny?Danny：No! Wait! (He puts on a raincoat and sits down.) Now I think I′m ready.Jenny：Brian，take your hand off the cardboard.Danny：No!　 (Danny closes his eyes tightly，and Brian takes his hand off the cardboard. The water stays in the jar.)Jenny：See，Danny!Danny：How is that possible?Brian：The force of the air keeps the water in the jar. It is strong enough to hold the water.Danny：Wow!Brian：So what have we discovered？Jenny：We have discovered that the air pressure helps the cardboard hold the water in the jar.Brian：Right. What do you conclude，Danny?Danny：I conclude that air is stronger than I 　 thought. Let ′s Do It ! 1．Where does Danny think they should do the experiment? Outside.2．What keeps the water in the jar?3．Is Jenny sure of her theory？How do you know?The force of air. Yes, she is. She asks Brian to do the experiment over Danny′s head and she knows he won′t get wet. 4．Why does Danny put on his raincoat?5．What does Danny conclude?He is afraid that he will get wet. He concludes that air is stronger than he thought. □Put a piece of cardboard over the jar.□The jar of water is upside down，but the water stays inthe jar. This is because air pressure pushesthe cardboard onto the jar.□Fill the glass jar with water.□Turn the glass jar over quickly. Hold your hand on the cardboard for a few seconds.□Remove your hand from underneath the jar. What happens?□There is more air outside the jar than inside，so there is more air pressure outside than inside.251346 Task tips：What happens when you use less water， more water，wet cardboard，or different kinds and sizes of jars?What is science?Can you explain?Please make it easy for my brain.It′s about making observations.Why do onions make me cry?Why do clouds go by?What keeps the birds in the sky?That′s just science.What Is Science?It′s about matter—the universe.Why does a car stay on the road?Why is there green all over a toad?Why can′t I carry a heavy load?That′s just science. Language point 1“做实验”可用 do/make/carry out an experiment表达。eg：Mr. Black is doing/making/carrying out an experiment in physics. 布莱克先生正在做一个物理实验。 experiment v.做试验，进行实验，常和介词 on，with 连用。eg：He is experimenting on frogs. 他正在青蛙身上做试验。 Language point 2反义短语为：turn...right side up 把……正面朝上。eg：Turn the box right side up, please. 请把这个盒子正面朝上放。eg：Can you turn the glass upside down? 你能把这个玻璃杯倒过来吗？Language point 3take off 脱掉，摘掉，(飞机)起飞eg：Bill took off his glasses. 比尔摘掉了他的眼镜。The plane will take off at 2：00 p.m. 飞机将在下午两点起飞。Please take your hand off the food. 请把你的手从食物上拿开。Language point 4get 作系动词，表示“变得”，后跟形容词作表语。eg：The weather will get cool when autumn comes. 当秋天到来的时候，天气会变得凉爽。Language point 5 此句是一般现在时的被动语态，That在这句话中充当主语，is called 构成被动语态结构。一般现在时的被动语态的构成为：be动词(am/is/are)＋动词的过去分词。eg：More money is saved by using both sides of paper. 通过使用纸的两面，更多的钱被节省下来了。典 例— Claudia， are you going to Jeff′s birthday party on Saturday?— Unless I________． A. will be invited　　 　B. am invited C. was inviting D. invitedB 【点拨】考查被动语态和时态。句意：——克劳迪娅，周六你打算去杰夫的生日聚会吗？——除非我被邀请。 unless引导条件状语从句，当主句(此处已省略)描述将来发生的动作时，从句中用一般现在时表示将来的动作。 Language point 6Language point 7一、根据句意及首字母或汉语提示补全单词1．It′s the best ________ of working out the math problem.2．I′m sure that the ________ of the air will keep the water in the jar.ethod　 orce 3．Can you help me ________ the mistake that you find?4．Put on the__________ (雨衣)for it′s raining heavily.5．Don′t turn the cup ________ (上部)down.orrect raincoat　 upside 二、单项选择6．Tom is covering the cup ________ a piece of paper. A．for B．on C．with D．in C7．I won′t force anybody ________ anything. A．do B．does C．to do D．Doing8．Mum wants to watch CCTV news. Let′s________ the TV. A．turn down　　B．turn on　　C．turn offCBTHANKS