“生活中的化学知识”双语教学课案例

文章编号：1005－6629(2009)03－0050－03中图分类号：G633.8文献标识码：B

1教学目标

让学生掌握9个化学术语：acidic\ basic\ neutral\ strong acid-weak base salt\ weak acid-strong base salt\ fire extinguisher\ chlorine\ alcohol\ solid-state.

培养学生用化学知识解决实际问题的能力（泡沫灭火器的制取原理、洗洁剂混用的危害、固体酒精的制法）。

让学生体会化学知识的重要性，感受学以致用的乐趣。

2 教学方法

先与学生讨论长大后的理想，引出大家都想为社会做出贡献的思想。那现在作为一名学生，我们也可以用我们所学来解决一些生活实际问题，进而引出本节课的主题：chemistry knowledge in daily life。接着通过化学知识在生活中的三个常见应用事例（泡沫灭火器的制取原理、洗洁剂混用的危害、固体酒精的制法）,由学生表演、实验、分析、讨论得出学习知识的重要性，最后教师作小结，希望学生们能学有所成，实现自己的梦想，与开头呼应。

3 教学过程

[第一部分 导入]

[先与学生讨论长大以后的理想，进而引到现在作为一名学生，我们可以用我们所学来解决一些生活实际问题，进而引到本节课的主题。]

Teacher: What's your dream? What kind of jobs would you like to do in the future?

Student1: I want to be a journalist.

Student2: I want to be an engineer.

Stndent3: I want to be a teacher， too.

Teacher: Good，in a word , we all want to make great contributions to our society. As a student, we can also use what we've learnt to solve some problems. Today, Let's enjoy three projects. Please try your best to find out the reasons for the three phenomena. OK, let's begin.

[第二部分 表演、实验、讨论、分析]

[讨论了化学在生活中的三个应用：泡沫灭火器的制法、慎用洗涤剂以及固体酒精的制法。主要采用的教学方式是由学生表演、学生实验为主，教师在适当的时候补充。]

[Project 1]

[旁白]: I have two friends, one is aluminum sulfate ,the other is sodium bicarbonate.

Student 1： Hello, everyone, I am aluminum sulfate, please read after me ,can you say something about my properties?

Student 2： Hello, everyone, I am sodium bicarbonate, please read after me ,can you say something about my properties?

Teacher: I will give you some words and expressions to help you.

acidic

basic

neutral

strong acid-weak base salt

weak acid-strong base salt

hydrolyze

[旁白]: One day , when they met together, what will it happen?

Student 1 and Student 2:表演反应的情景。（学生1和学生2打斗过后，彼此互换了衣服，学生1的帽子飞起来了，学生2躺倒在地。打斗：表示在剧烈地反应；互换了衣服：表示反应后有新物质生成；帽子飞起：表示生成了气体；倒在地上：表示生成了沉淀）。

教室里掌声如雷。

Teacher: Who can write down the reaction equation on the blackboard?

[Experiment]：请两位学生上来做实验。装置如图所示。

Teacher: You see, we can put out fire easily in this way. According to this theory, we can make out “fire extinguisher”.

[教师展示实物并提问]：There are two buckets in fire extinguisher, the inside one is made of plastic, the outside one is made of iron. How to put aluminum sulfate and sodium bicarbonate? When we use it, what should we pay attention to?

Students：We should put aluminum sulfate into the bucket which made of plastic and put sodium bicarbonate into the bucket which made of iron. When we use it, we should turn it upside down.

[Project 2]

[旁白]：Mary is a very busy woman , she works in the office from day to night. Sometimes she even works on holidays. So there is little time for her to do some cleaning. Today is a special day ,she needn't go to work. She wants to clean the house. First , she chooses to clean the closestool.

[表演]:玛丽清洗马桶。（她先倒了些“洁厕净”，边用刷子刷，边哼着“洗唰唰”的歌，洗了一会，看看效果不怎么好，她把家里其他的洗涤剂都找了出来，她把每种洗涤剂都倒进一点，又刷了一遍，正当她要站起来时，一阵头晕，她昏倒在地。另两位学生把她抬出教室后，进来一位“医生”，手举一牌，上面写着：氯气中毒。）

Teacher: Do you find out anything wrong? What does it happen? Why does Mary faint?

[学生讨论]

[幻灯片显示]：在我们日常生活的清洁剂中，洗洁精和厨房消毒剂是含次氯酸的氯烃化合物，洁厕净和浴池清洁剂则是酸性洗涤剂，当两者混合时，容易发生化学反应产生氯气。氯气比空气重，易积存在卫生间的底部。

Teacher: Mary takes in a large amount of chlorine , so she faints. From now on , please tell your mother not to put substance cleaning the toilet and substance cleaning the bowl together. It is dangerous.

[Project 3]

[猜谜] It's a puzzle. I will give you three pieces of information. Try your best to guess what it is as quickly as you can.

It can be found everywhere, such as in the hospital ,in the restaurant and so on.

It exits in a liquid form. It can be lit.

If you drink too much especially before driving , you will be faind by the policeman.

What is it? Who can write down this word on the blackboard?

Student 1: alcohol.

Teacher: We know, in normal temperature, alcohol is a liquid, but sometimeswe can see some solid-state alcohol. What is it? How to make it?

Students: increase the pressure、low the temperature.

[幻灯片显示]：固体酒精的制法（先配制一定温度下的饱和醋酸钠溶液，然后在溶液中慢慢加入无水乙醇，冷却，即可得到固体酒精。）

[Experiment]：请学生上来根据幻灯片显示做实验。做好后，点燃固体酒精。

[幻灯片显示]：酒精的熔点是－117.3℃，固体酒精并不是固体状态的酒精，而是醋酸钠与酒精形成的凝胶。醋酸钠易溶于水而难溶于酒精，当两种溶液混合时，醋酸钠在酒精中形成凝胶而析出，液体逐渐由浑浊到稠厚，最后凝聚成为一整块，这就是固体酒精。

[第三部分 小结]

[在这三个应用中，有些混用物质是有用的，有些是有害的，鼓励学生努力学习，实现自己的梦想，与开头呼应。]

Teacher: In the three experiments ,we all mix two different substances together. Some do good to us, some do not. Whether it is useful or not depends on the way we use. So I hope you can make good use of your knowledge and make great contributions to our society. I'm sure you all can make your dreams come true!

4自己的体会与反思

我校双语教学还处于起步阶段，在这个阶段，关键要先激发学生对双语学习的兴趣，为此我设计了多个学生活动的环节，如表演、猜谜等，化抽象为形象，课堂气氛较活跃。

利用化学学科得天独厚的优势，我充分发挥了实验的作用，这样比直接说教效果好。

本节课的目的是想让学生掌握几个较常用的化学术语的英语表达，而有些化学原理的解释，全用英语解释，担心影响学生的理解，所以选择了用幻灯片以中文形式解释。

学生的表演很精彩，让我深受感动。我感受到了他们的青春活力、他们的创造力以及他们的表演能力；我也深深感到要让学生喜欢这门课，教师要多开发一些与生活实际紧密相连的知识，让学生觉得学有所用，求知欲会更强。

不足的地方：原理的解释用幻灯片显示或教师自己解释较多，可以多设置一些小问题，尝试由学生用英语来讨论，真正达到双语教学的目的。