冀教版九上英语 Unit 5 Look into Science.Lesson 26 Keep the candle burning.课件(共16张PPT)

(共16张PPT)
do an experiment
Unit5:Look into Science
Lesson 26:
Keep the Candle Burning!
一:学习目标
1.掌握词汇：match
2.接触词汇：holder、shallow、lighter、
examine、oxygen
3.短语和句型: use up; be made up of
二:重点与难点
1.重点：学习如何做实验的表达方式。
2.难点：熟练运用目标语言谈论所做过的实
验。
3.分数的表达方法。
New words
holder n. 支托物；持有者
shallow adj. 浅的
lighter n. 打火机；点火器
match n. 火柴
examine v. 检查
oxygen n. 氧气
Think about it
1.Do you think science is interesting : Why or not
2.Name one or two famous Chinese scientist. What do you know about them
What do you need
· a candle
· a big glass jar
· a shallow dish with water
· a candle holder
· a lighter or matches
What do you do
1. Put the candle in the candle holder.
2. Put the candle holder on the dish.
3. Fill the dish half full with water.
4. Light the candle.
5. Let the candle burn for two or three
minutes.
6.Carefully put the jar over the candle until
the top of the jar rests on the dish
7. Examine the water in the jar. What can you see
What is happening
As the candle burns , it uses up oxygen in the air. When the candle stops burning, it has used up all the oxygen in the jar. The water inside the jar rises. How far does the water rise Because about one-fifth of the air is made up of oxygen , the water rises and fills about one-fifth of the jar.
Language Points
1.Keep the candle burning! 让蜡烛燃烧！
keep…burning 使……燃烧。
keep sth. (sb.) doing, 使某物（某人）保持做某一动作。
eg:不要再让水继续流了。
Don’t keep the water falling.
2. As the candle burns, it uses up oxygen in the air.
当蜡烛燃烧的时候，需要消耗空气中的氧气。
use up 用光，耗尽。表示完全，彻底。
eg:吉姆为了买电脑花光了所有的钱。
Jim used up his money to buy the
computer.
3. There is about one-fifth oxygen in the air, so the water rises and fills about one-fifth of the jar.
氧气在空气中占五分之一，所以水面上升并且占据了瓶子的五分之一。
one-fifth 五分之一。
我们来归纳一下分数的表达：
如：1/3，三分之一,
1/5, 五分之一,
3/4, 四分之三,
2/5, 五分之二 ,
注意：分数做主语时，谓语动词和它后面的名词保持一致。
分数由分子及分母两部分构成。用英语表达时，分子用基数形式，分母用序数词形式。若分子为1时，则分母的序数词为单数形式，若分子大于1时，则分母的序数词用复数形式。
one third
one fifth
three fourths
two fifths
4. Because about one-fifth of the air is made up of oxygen , the water rises and fills about one-fifth of the jar.
因为空气的五分之一是由氧气组成的，所以水会上升到瓶子五分之一的位置。
例：一切动植物都是由细胞组成的。
be made up of 由……组成
All animals and plants are made up of cells.
根据汉语意思完成句子
1.不要让昨天消耗太多的今天。
2.我们班是由男生和女生组成的。
3.三分之二
Don't let yesterday use up too
much of today.
Our class is made up of girls and boys .
two thirds