初中英語(yǔ)河北加拿大版學(xué)生用書(shū) 27

所屬教程:初中英語(yǔ)河北加拿大版學(xué)生用書(shū)

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[by:喜歡tingclass.net，請(qǐng)把tingclass.net告訴你QQ上的5位好友，多謝支持！] [00:00.00]聽(tīng)力課堂網(wǎng) Lesson 27: [00:03.58]Let's Do an Experiment! [00:07.24]One Experiment,Two Theories [00:11.81]A "theory" is an idea.A theory predicts what will happen. [00:18.57]An experiment shows what happens. [00:23.25]BRIAN:Did you read about this experiment,Danny? [00:27.69]I fill a jar with water. [00:31.76]I cover the top with a piece of cardboard. [00:36.52]Then,I turn the jar upside down. [00:41.87]JENNY:Guess what will happen! [00:45.53]DANNY:I'm not sure. I think the floor will get wet. [00:51.70]Maybe you should do this experiment outside,Brian! [00:57.65]BRIAN:No,we can do it inside.I'm sure the floor won't get wet. [01:03.71]DANNY:Why not?The cardboard can't keep the water in the jar! [01:10.19]JENNY:Let's do the experiment and see what happens. [01:15.65]Brian has one theory and Danny has another. [01:22.13]We can prove who's right. [01:26.49]BRIAN:Great!We'll do the experiment and make observations. [01:32.37]That's called scientific method.Weird Mud! [01:39.32]This experiment shows two new words:"liquid" and "solid" [01:47.57]What's a liquid? Water is a liquid. [01:52.93]What's a solid?In this experiment, [01:58.39]you make something that's a liquid sometimes and a solid sometimes. [02:05.23]What do you need? a bowl,a spoon, cornstarch,water [02:14.19]What do you do? [02:17.35]1.Put eight spoonfuls of cornstarch into the dish. [02:25.01]What's a "spoonful" of cornstarch? [02:29.26]When you fill a spoon with cornstarch,you have a spoonful. [02:35.32]2.Add four to five spoonfuls of water [02:42.09]3.Mix the cornstarch and water together [02:48.33]4.Pour the mud into your hand. [02:53.90]5.Open and close your hand.What happens to the mud [03:02.07]What is happening? Some things dissolve in water. [03:08.84]Sugar dissolves in water.But not cornstarch.It only mixes with water. [03:18.22]When you close your hand,you squeeze some of the water out. [03:24.46]The mud becomes solid.When you open your hand,the water mixes in again. [03:33.42]Now it is a liquid!What else can you do [03:39.79]Put some of the mud in a bowl. [03:43.95]Now hit the mud with your open hand. [03:48.81]In English,we say that you are"smacking" the mud. [03:54.87]What happens?Now do the same thing with water. [04:01.32]Are the mud and water the same when you smack them?

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