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第 5 课 时
Unit 6 Looking into science
Lesson 5 Keep the candle burning!
单词：match，light，examine
短语：fill...with...，used up，be made up of
句型：①Fill the dish half full with water.
② As the candle burns, it uses the oxygen in the air.
③ As about one fifth of the air is made up of oxygen, the water rises and fills about one fifth of the jar.
能阅读并理解关于蜡烛燃烧实验的文章并找出该实验的主要步骤和结果；能用英语规划、组织并展示一个简单的实验。
Learning Goals
1
2
Lead-in
Look at things of the candle experiment and observe.
What materials can you see
What do you think will happen if we
cover a burning candle with a jar
Will the candle keep burning
What might happen to the water
Skim the passage and and match the materials on your book with the things on the desk.
1
a candle holder
a shallow dish
a lighter or matches
a candle
a big glass jar
some water
Fast reading
What do you need
a candle a candle holder
a big glass jar a shallow dish
some water 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. Carefully put the jar upside down over the candle until the top of the jar rests on the dish.
6. Examine the water in the jar
What do you see
The water inside the jar rises and fills about one fifth of the jar.
Why does this happen
As the candle burns, it uses the oxygen in the air. When the candle stops burning, it has used up all the oxygen in the air. As about one fifth of the air is made up of oxygen, the water rises and fills about one fifth of the jar.
Read the passage carefully and write true (T) or false (F).
2
Careful reading
A: We need a very deep dish to finish the experiment. ( )
B: The candle stops burning because it has used up the
oxygen in the jar. ( )
F
T
What do you do
What do you do
until the top of the jar rests on the dish
Read the passage carefully in groups, draw a flowchart of the experiment procedure, and retell it in your own words.
3
Summary
When a candle burns inside an upsidedown jar, it uses up oxygen in the air. About one fifth of air is made up of oxygen. So the candle goes out and water rises inside the jar to take up about one fifth of the jar’s space.
Key phrases
a candle a candle holder a big glass jar a shallow dish
fill … half full with water light the candle upside down
use up be made up of one fifth
Imitate the experiment and describe each step of the operation in English and present imitation to the class.
Tips:
First, ... Then, ... Next, ... Finally…
Discussion on the experiment result.
Why does the water rise
What does this tell us about air
4
Complete the experiment report table.
What experiments have you done before that impressed you most Share with your partner.
5
A What experiment was the most fun for you
B Which experiment was the most challenging
C Did you get any promising results while
experimenting in the lab
D What do you enjoy most about doing experiments
Work in groups of three. Pick a fun and easy experiment and present it to the class.
6
Discuss and decide
Discuss and decide on an experiment that is easy, safe, and interesting. You can search the internet for an idea and find out how to perform the experiment properly.
Write
After you have made your group decision, write down the specific steps of the experiment. Then describe what should happen.
Present
One student reads out each step while the second student does the experiment.
Comment
After the experiment, the third student makes observations on what has happened and why.
Measure the Resistance of a Small bulb测量小灯泡的电阻
What do you need
three battery boxes 三个电池盒
three No.1 dry cell batteries 三节 1 号干电池
a small bulb (rated voltage: 2.5 V) 一只小灯泡（额定电压：2.5 伏）
a switch 一个开关
a student ammeter一块学生电流表
a student voltmeter一块学生电压表
a sliding rheostat (max resistance: 20 Ω) 一个滑动变阻器（最大阻值：20 欧姆）
some plug in wires若干插片导线
What do you do
1. Use wires to join the battery, switch, ammeter, rheostat and small bulb together in series.
用导线把电池、开关、电流表、滑动变阻器和小灯泡串联接好。
2. Put the voltmeter across the two sides of the small bulb.
把电压表接在小灯泡的两端。
3. Check all parts of the circuit, then turn on the switch.
检查全部电路，再闭合开关。
4. Move the rheostat’s slider little by little. 慢慢移动滑动变阻器的滑片。
5. Look at the ammeter and voltmeter, and write down their numbers.
观察电流表、电压表，并记下读数。
6. Do this again to get more sets of numbers. 重复操作，得到多组数据。
What do you see
When you move the slider, the small bulb becomes brighter or darker.
移动滑片时，小灯泡会变亮或者变暗。
The numbers on the ammeter and voltmeter change too.
电流表、电压表的读数也跟着变化。
You get many different pairs of voltage and current numbers.
你会得到多组不一样的电压、电流数值。
Why does this happen
The rheostat can change how hard electricity moves in the circuit.
滑动变阻器可以改变电路中的电阻。
It changes the electricity going through the bulb and the voltage on the bulb.
它改变流过灯泡的电流和灯泡两端的电压。
With Ohm’s rule, you can use voltage and current to find the bulb’s resistance.
根据欧姆定律，利用电压和电流就能算出灯泡的电阻。
The bulb gets hot when it works, so its resistance changes a little.
灯泡工作会发热，所以它的电阻会有小幅变化。
What do you need
some vinegar一些白醋
some baking soda一些小苏打
a glass cup一个玻璃杯
What do you do
1. Pour some vinegar into the glass cup.
往玻璃杯中倒入一些白醋。
2. Add a little baking soda into the cup.
向杯子里加入少量小苏打。
3. Watch what happens carefully.
仔细观察发生的现象。
What do you see
Lots of bubbles come out quickly. The liquid in the cup rises and boils.大量气泡快速冒出，杯中的液体翻腾上升。
Why does this happen
Vinegar and baking soda mix and react. They make carbon dioxide gas. That is where the bubbles come from.
白醋和小苏打混合后发生化学反应，生成二氧化碳气体，气泡就由此产生。
Vinegar and baking soda reaction白醋与小苏打反应
The class votes for the most interesting experiment.
7
1. a lighter or matches 打火机或火柴
Language points
match n. 火柴；比赛 v. 相配；匹配
例句: You cannot play with matches at home.
你在家不可以玩火柴。
例句: We will watch a football match this weekend.
这周末我们要看一场足球比赛。
例句: The blue tie matches your suit very well.
这条蓝色领带和你的西装很搭。
light
① v. (lit /lighted) 点燃；点火；照亮
② n. 光；光线；灯
③ adj. 轻的；浅色的
例句: She lit the fire to keep warm.
她点燃火堆来取暖。
例句: The bright light hurt my eyes.
刺眼的灯光伤到了我的眼睛。
例句: This bag is light enough for kids to carry.
这个包很轻，孩子拿得动。
2. Light the candle.点燃蜡烛。
examine v. 检查；仔细审查；考察
examination n. 考试；检查
例句：The doctor will examine your throat first.
医生会先检查你的喉咙。
例句：Teachers examine students’ homework carefully.
老师们仔细审阅学生的作业。
3. Examine the water in the jar. 检查罐子里的水。
4. When the candle stops burning, it has used up all the oxygen in the air.当蜡烛停止燃烧时，它已经耗尽了空气中的所有氧气。
use up 用完，耗尽
eat up 吃光；吃完 drink up 喝光；一饮而尽
burn up 烧尽；烧光 clean up 清扫干净；收拾完
例句：We have used up all our paper.我们已经把所有纸都用完了。
例句：The kids ate up all the cookies.孩子们把饼干全部吃光了。
5. As about one fifth of the air is made up of oxygen, the water rises and fills about one fifth of the jar.由于大约五分之一的空气是由氧气组成的，所以水会上升并充满罐子的五分之一。
be made up of 由…… 组成
be made of 由…… 制成（肉眼看得见原材料）
be made from 由…… 制成（看不出原始原料）
例句：Our class is made up of 45 students.
我们班由 45 名学生组成。
例句：The table is made of wood.这张桌子是木头做的。
例句：Wine is made from grapes.葡萄酒由葡萄酿造而成。
选词填空
Practice
1. He ______ a match to start the small fire last night.
2. Don’t hold the bottle ____________, or the juice will run out.
3. The doctor will _________ your eyes before you take the medicine.
4. If you keep working day and night, you will ________ your energy.
5. This sports team ______ ______ ____ ___ seven young players.
lit
upside down
examine
use up
is made up of
examine use up be made up of upside down light
1. Write a short passage describing the “Keep the candle burning!” experiment. Include: materials, steps, result, and principle. (Required)
2. Design a similar small experiment about air or burning that you can do at home. Write down the steps and what you expect to see in English. You may take photos or a short video to record it.
Homework

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