《Primary battery》原电池双语教学设计
无锡市第一中学 化学组 李桦

教学背景：
　　双语课，作为一种新型的课堂教学模式，自出现以来一直吸引着教育界乃至非教育界人士的注意；对双语教学大加赞赏者有之，口诛笔伐者亦有之。究竟双语课给课堂教学带来怎样的冲击、改变和思考。我也想不断的实践探索。因此设计了原电池的这节双语课。
认知目标：
1、 以英汉双语的思维形式认识原电池的原理、本质、形成条件。
2、 了解常见电池的简单构造，性能、特点。
3、 培养学生自主探究的能力和兴趣。
4、 学习相关的化学专业词汇和表达方式，从而达到化学学习和英语学习的结合与延伸。
语言目标：
　　掌握一些化学的专用名词和术语、专用的句型及固定表达法，使学生逐步掌握化学的专用术语与语句，独特的语言结构与表达法，能初步听懂该学科的英语授课，读懂该学科的英语教学资料，进而发展成能用英语就该学科的问题进行口头交流与书面交流。

教学准备：
相关生词，学生课前预习
Primary battery 原电池 Zinc 锌
Copper 铜 bubble 气泡
dissolve 溶解 Sulfuric acid 硫酸
Hydrogen 氢 Ammeter 电流计
deflect 偏转 current 电流
electron 电子 redox reaction 氧化还原反应
oxidize 使氧化 reduce 还原
Electrode 电极 Cathode 负极
Anode 正极 Electrolyte 电解质溶液
Magnesium 镁 Voltage 电压
recycle 循环，反复 Dry cell 干电池
Carbon rod 碳棒 Manganese dioxide 二氧化锰
Ammonium chloride 氯化铵 Alkaline 碱性的
Lead storage battery 铅蓄电池 Lead 铅
Lead dioxide 二氧化铅 Lithium 锂
Novel fuel cell 新型燃料电池 Alkali 碱

课前调查：
　　Investigate categories, use range, properties, price, oxidants and reductants of common cells. Investigate how to deal with the waste cells, and the value of recycling waste cells.

实验准备：
演示实验：锌片，铜片，稀硫酸，导线，电流计
学生实验探究：铜丝，镁丝，音乐卡，水果。
实物准备：干电池，手机锂电池，电动车的铅蓄电池。

教学过程设计：
情景引入：学生小品表演"What did Mrs. Green suffer after all?"
Mrs. Green is a pretty, optimistic lady. But when she burst into laughter, people found her two front teeth were false. One is made of gold, the symbol of her wealthy; another one is made of stainless steel, a symbol after a traffic accident. What puzzled everyone is that she always felt headache, sleepless and fidgety since the traffic accident. The doctors used every means, but still could not cure her. Later, a young chemist visited her and found out the cause at last.
提出疑问：Can chemical energy change into electrical energy ? How to change?
演示实验：铜锌原电池反应。
　　学生描述实验现象，教师引导分析实验现象,关键是气体为什么在铜片上产生。并且归纳总结
Cathode Zn - 2e- =Zn2+ oxidation
Anode 2H++ 2e- = H2 reduction
This experiment has shown the current is really produced by the transmission of electrons in a redox reaction.
引出原电池的概念The device that converts chemical energy to electrical energy.
规定原电池中的正负极。
分析原电池反应的本质是氧化还原反应
探究构成原电池的条件：由教师给出六组装置，学生通过观察、比较、分析、思考、讨论得出结论：
Two different metals to be the electrodes, or one is not metal but conductor.
Electrolytes should be stuffed between two electrodes.
The whole circuit should be closed.

学生自主探究：
　在知道了以上三个条件之后，学生自己动手，从身边找实物，设计原电池。教师提供铜丝、镁丝、音乐卡。
过渡:
　　In fact the primary batteries above are very simple. They are only used in experimental teaching. In modern battery industry, kinds of practical batteries have been produced.
投影展示日常生活中的各种各样的实用电池。
提问：To be practical, what features the batteries should have?
学生自由发表意见：
　　Be able to produce a stable current.
　　They should be safe, convenient to carry.
　　Be useful in special field.
　　Be easy to recycle, not polluting the environment.
　　由于学生在课前已经对一些常见的电池已经作了积极的调查。
　　Investigate categories, use range, properties, price, oxidants and reductants of common cells. Investigate how to deal with the waste cells, and the value of recycling waste cells.
　　请一位学生汇报调查结果。
　　中英文并用，在难以表述的地方教师加以补充说明。让学生认识到在学习中应该具有积极调查和研究的精神。 在学习了原电池的基本原理的基础之上，由教师对一些常见类型的电池作简要的介绍。
1、 Dry cells (干电池）
　　投影展示Zn-MnO2 干电池的结构图，提问学生: what is the cathode or anode? What is the electrolyte? 学生不难给出答案。
介绍这种电池是碳性干电池 carbon dry cell ,具有更杰出性能的各种碱性干电池（alkaline dry cells）应运而生。
2、 Lead storage batteries (铅蓄电池）
　　投影展示图样、实物（电动车中用的电池）简介构造：
cathode : Pb (lead) anode : PbO2 (lead dioxide)
electrolyte: H2SO4(aq)
Lead storage batteries are widely used in many fields. They are safe ,convenient, reliable and can be reused.
3、Lithium cells （锂电池）
　　投影展示一张笔记本电脑使用的锂电池图。介绍它们的突出优点是质量非常轻，电容量却很大，因而被广泛应用于精细科技领域，如电脑，相机，手表，甚至用于心脏起搏器中。
　　投影展示一张心脏起搏器（heart pacemaker）的图。
4、Novel fuel cells （新型燃料电池）
A widely used fuel cell is H2 and O2 fuel cell .unlike the batteries above, fuels cells do not store reactants in their cells .when they begin to work, reactants must be constantly supplied, and the products must be removed from the cells in time. So they are really energy --- conversion machine.
And their efficiency is very high , even can reach up to more than 70℅.Another big advantage is they have no pollution, because the product is water.
　　通过以上的介绍是学生了解到各种各样的电池给我们的生活带来了极大的方便。但凡事总要一分为二。它们也带来一些负面影响。

学生发言：
1、Waste cells contain many harmful materials, such as heavy metals, acids, alkali.
2、But some metals in waste cells are valuable resources. If the waste cells can be recycled, the damage to the environment will decrease, and resources will be saved.
　　投影展示一些城市设立的废旧电池回收站。让学生树立环保意识，节约意识。
学到这里，回到一开头的情景短剧。解决疑问。

2006年4月