英语：Unit 4 Look into Science Lesson 30课件(冀教版八年级下)

Lesson 30Keep the Candle Burning!

Ⅰ. Learning aims:◆

知识目标 Master the new words: match, light, burn, use up, shallow, candleholder, oxygen,one-fifth 2) The important sentences: ① Fill the dish half full of water. ② As the candle burns, it uses up oxygen in the air. ③ There is about one-fifth oxygen in the air, so the water rises and fills about one-fifth of the jar. ◆能力目标 ：can describe and explain the experiment in English ◆情感目标：Cultivate the spirit of loving science.

Ⅱ. 教学重点：1. Describe and explain the experiment inEnglish.2.分数的表达法 Ⅲ.教学难点:Describe and explain the experiment in English.

预习早知道n. 火柴;比赛 matches 1.match (pl)----__________ lighted/lit light (过去式)___________( 过去分词)lighted/lit v. ____________________ 点燃;使燃烧/照亮;使光明 burn(过去式)___________ (过去分词) burned/t ________ v. 燃烧 burned/t use up 用完；用光； one--fifth 五分之一 deep shallow(反义词)________ halves half(pl)______

Look and Learnmatches 1 .What are they ?They are________ light something. I They are used to _______ to light candle. will use them ________a I am _______ lighting the candle with the match. My father often uses light matches to _______his smoke. 2.This afternoon we’ll have a match basketball_______.

Look and LearnWhat’s this? It’s a______ candle .It’s a burning candle . If I put the jar over the _______ burning candle, what will happen?burning why? ----It will go out / stop _______ oxygen . -----Because burning needs _______ when the candle stops buirning, it has up all the oxygen in the jar. ___ ____ used up all the use up (______:They have used _______ water. )

一. 自主探究，合作学习put in 1.He _____the spoon____the bowl.他把汤匙放到了碗里面。with 2.Lily _____the bottle____water. Lily 把瓶子装满了水。 filled3.The room is ___________________ full of/is filled with smoking. 屋子里充满了烟。

over 4.Please put the jar _____the candle.请把罐子放到蜡烛的 上面。 used up 5.My mother________her money to buy clothing yesterday.我妈妈昨天买衣服花光(用光)了她身上所有的钱。

two-thirds one-third 6.In our class,______ students are boys,______ students are girls. 在我们班，三分之二的学生是男生，三分之一的学生 是女生。二. 小组合作操练，用上述新知识点造句，并在小组 内核对，交 流。

点拨

Comepare and Find分子 分母分数表达法分子基分母序

. There is about one-fifth oxygen in the air, so thewater rises and fillsabout one-fifth of the jar.

Practise 1/4 one-fourth a quarter

基数词 序数词

1/5 4/5 1/3 2/3

One - fifth

four – fifthsone - third 分子大于 1 two - thirds 分母加 S

3/7 three-sevenths5/9

five-ninths

强化训练单项选择

A 1.The bottle is only____full. A.half B.a half2.She ____the chicken bones to make soup.

C http://www.77cn.com.cned for B. used to http://www.77cn.com.cned up

C. halfs D.halves

http://www.77cn.com.cned with

3.___of D the students in our school____from countryside.(乡村)A.Four-fifths,comes B.Fourth-five,come C.Four-fifth,come D.Four-fifths,come

C 4.____of water____. A. Three-fourths, are B.Three-four,is C.Three-quarters,is D. Three-fourth, is C 4.The river is _____here; we can walk across. A. deep B. fast C. shallow B 5.Yellow is a _______colour, but black is dark. A. orange B. light C. heavy

Watch ,Say,answer and FillHow do we do the experimentFirst. _____the put candle ____the in candleholder. put in Then. _____the candleholder ____the dish. Fill half full of Third. _____the dish ___________water . Light Fourth. ______the candle . burn let Fifth. ______the candle ______for two minutes . put over Sixth.carefully____the jar_____the candle rests until the top of the jar_____on the dish.

What observation can you make?

Think ,Read and Anwser1. Why did the candle stop burning ?no because there was ___oxygen in the jar .

2. Why did the water rise ?The force outside the jar is stronger ______ than the force inside the jar .

3. How far did the water rise ? Why?one-fifth It rose about ____________of the jar . air Because there is one-fifth oxygen in the_____.

summaryThe new words: match, light, burn, shallow, candleholder, oxygen, The phrases and expressions: use up, one-fifth, keep sb/sth doing, keep sth/sb +adj Stop doing/to do sth, put….in/over 分数的表达：分子基，分母序，分子大于 1,分母加 S sentences ① Fill the dish half full of water. ② As the candle burns, it uses up oxygen in the air. ③ There is about one-fifth oxygen in the air, so the water rises and fills about one-fifth of the jar. How do “ keep the candle burning”

用所给单词的正确形式填空：to have 1.You are very tired. You’d better stop ______(have) a rest. burn 2. What do you use to make a candle ________(burn)?

carefully 3. You should put the jar over the candle ________(careful).observation(s) 4. What ______________(observe) can you make?

halves 5. Please cut the apple into __________(half).lighted/lit 6. He __________(light) a candle and the room was bright. burning 7. He kept the candle _________(burn) for two hours. to play 8. It’s time ___________(play) basketball.

healthy 9. Eating green food can help to keep you __ ____ (health). waiting(wait) for a long time. 10.I’m sorry, I kept you______

Homework:1.Read the text aloud and recite the experment of this lesson.

2. Write “How do …”that you have learned in this unit3.Preview lesson31.

Class is overBye-bye!