初中英语河北加拿大版学生用书27

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[00:00.00]和谐英语学习网 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?