高中化学实验的巧妙应用和趣味.docx

实验教学是化学教学的有机组成部分，注重学生实验技能和创新精神的培养，有利于学生掌握理论知识和科学研究方法。但是，现在的应试教育使化学实验教学难以发挥出它应有的作用，实验教学成为教师讲、学生做、教师示范、学生模仿的教学，学生缺乏主动探究的欲望和热情。那么，教师如何在教学中让化学实验巧妙应用并且具有趣味性呢？一、合理安排学生的实验时间，有效培养学生的探究技能为了完成教学任务、节省时间，很多教师会选择做演示实验，导致学生动手机会降低，实验技能得不到加强。因此，教师应该想方设法增加学生的实验时间，充分利用学生的课外活动时间开展兴趣小组和自行实验活动。课外活动时间充足，可根据不同学生的爱好和兴趣，有针对性地做一些实验，而达到培养学生动手能力的目的。例如，在讲硫与金属反应的课前，本人会先简述电视剧里常有银针试毒的情景，然后设问银器真的可以试毒吗？银器变黑究竟是“中毒”还是普通的化学反应？然后，引导学生在课前查阅资料并利用自己的银饰品做一系列的课外实验。学生实验结果显示，除了猕猴桃外，鸡蛋蛋黄也会让银器变黑，而真正有毒的杀虫剂、蟑螂药等却不能使银器变黑。学生很是惊讶。教师解释古代生产技术落后，砒霜里含有或多或少的硫及硫化物，这些硫与银器反应生成黑色的硫化银让银针变黑。现如今，砒霜产品中含硫量极低，使用银器直接接触不再会有明显变化，这种验毒方法也就失去了应用的价值。可见银针可以试毒是假的，而像猕猴桃、蛋黄都是因为含有硫或硫化物，而导致银器变黑。而这些食物中的硫化物对人体是没有危害的，同学们不必担心、学生学习的兴趣极大地得到提高。让学生写出方程式：2Ag+S=Ag2S，并学会从氧化还原的角度分析得出S为氧化剂，Ag为还原剂，从而引入新课让学生自行书写并总结出其他金属（Fe、Cu、Na等）与硫反应有什么不同点和相同点。例如，在讲解碘的性质时，我通常课后会给每个学生发些淀粉碘化钾试纸，让学生利用食用白醋去检验碘盐中碘元素的存在；在讲解溶液酸碱性时，通常课后会发给学生一些pH试纸让他们去测试身边的常用品；让学生亲自用水果做原电池实验，用食用醋去泡鸡蛋等。这样，学生实验的体验得到了加强，实验的情感得到了升华，实验的兴趣发生了质的飞跃，学生的探究能力就会迅速得到提升。这些课外实验的顺利进行可以让有强烈求知欲且有不同需要的学生各得其所，生活实际、教学理论和实验相结合使他们在愉快的气氛中积极主动地动手动脑而获得知识，增强能力。二、增加趣味性实验，激发学生的好奇心理和探求欲望教师应该精心组织和设计实验内容，把课本知识和生活实际联系起来。例如，在讲酸碱指示剂通性时，就可以让学生自行揭秘江湖骗术血手印，先把酚酞喷在一张白纸上晾干，然后用手沾点碱水，按在白纸上就会有血手印出现，搁到水盆（水里兑了稀盐酸、白醋等）里变无色了，原理是酚酞遇碱变红遇酸变无色，血光之灾纯属无稽之谈，让学生学会分辨生活中的伪科学。同样的还有用FeCl3喷在黄色草纸上晾干，然后用手沾点水（水中兑了无色的KSCN溶液），按在草纸上会有血手印出现，原理是Fe3+与SCN-发生结合反应生成血红色物质。例如，在讲I2的物理性质时，让学生分成几个小组做指纹鉴定实验，取一张干净、光滑的白纸条，用手指在纸条上用力摁几个指印，将芝麻粒大的一粒碘，放入试管中，再把白纸条悬于试管中（注意摁有手印的一面不要贴在管壁上），塞上橡胶塞。把装有碘的试管在酒精灯火焰上方微热一下，待产生碘蒸汽后立即停止加热，发现纸条出现明显的个人黄色指纹印迹，进而让学生深入了解了I2易升华和易溶于有机溶剂的性质。用碘液检验学生从超市买来的香肠中的淀粉含量（I2遇淀粉变蓝）。这样的情景并不是每一节课都能设计，但至少向着这一方向努力，在学生亲自动手操作的过程中可把实验中每一个微小的现象都看得清清楚楚，它能更好地调动学生的学习主动性，有利于学生观察能力、思维能力和动手能力的培养。总之，在化学教学中，生动有趣和联系生活实际的实验有利于调动课堂气氛，几乎学生都会动手动脑去设法完成这些有趣的学习和实验，真正追求寓教于乐、寓教于新、寓教于创造。任何事情实践过就容易理解得清楚，让实验和理论结合这就更有可能激发出学生的创造力、探究力和想象力，并在乐趣中获得知识、巩固知识，也许课后学生还会有兴趣设计出更多的新内容、新项目，并去验证、去试验，大胆地去完成他们自己的想法，在实验中获得新知，从而有效提高教育教学质量。Experimental teaching is an organic part of chemistry teaching, pay attention to training students experimental skills and innovation spirit, is good for students to master theoretical knowledge and scientific research methods. But now, the exam-oriented education make the chemical experiment teaching is difficult to play its proper role, become teachers speak of experiment teaching and students, teachers demonstration, students imitate the teaching, students lack of initiative enthusiasm and desire to explore. So, how teachers in the teaching of chemical experiment clever application and have fun?One time, reasonable arrangement of students experiment, cultivate the students inquiry ability effectivelyIn order to complete the teaching task, save time, many teachers would choose to do the demonstration experiment, result in students opportunities to reduce, not strengthen experiment skills. Therefore, the teacher should find ways to increase the students experiment time, make full use of the students extracurricular activity time interest group and the experimental activities on its own. Activities out of class time is enough, can according to different students hobbies and interests, targeted to do some experiments, and achieve the goal of training students ability. For example, in the reaction of sulfur and metal before class, I will first briefly TV play often needles try poison, and then establish the silver really can try poison? Silver black is poisoningwww.jxzljn.com www.itengta.cn www.lin-jian.cn or ordinary chemical reactions? And then, guide the students in class data access and use his silver ornaments do a series of extracurricular experiment. Students experimental results show that, in addition to the kiwi fruit, egg yolk could make silver black, and truly toxic pesticides and cockroach medicine cannot make silver black. The student was surprised. Teachers to explain ancient backward production technology, the arsenic contained more or less of sulfur and sulfide, sulfur react with silver to generate these black silver sulfide let silver needle. Nowadays, arsenic low sulphur content in the products, the use of silver direct contact will no longer have obvious changes, this method of inspection poison will lose the value of application. Visible needles can try poison is false, and like kiwi fruit, egg yolk, all because of containing sulfur or sulfur, and lead to silver black. And these sulfides in food is no harm to human body, the students dont have to worry about, the students interest in learning was improved greatly. Let the students write equations: 2 Ag + S = Ag2S, and learn to analysis from the perspective of REDOX S as oxidant, Ag as the reducing agent, to introduce new lesson to let the students to write and sums up the other metal (Fe, Cu, Na, etc.) what are the differences and similarities with sulfur reaction. For example, in the interpretation of the nature of the iodine, I often after class to each of the students some starch potassium iodide test paper, let the students use of edible vinegar to test the existence of iodine in iodized salt; In the interpretation of the acid and alkaline solution, usually after class to students around some pH test paper to let them to test often supplies; Let the student galvanic cell with fruit on experiments, with vinegar to eggs, etc. Are enhanced in this way, students experiment of experience, the experiment of emotions got the sublimation, the experiment interest has had the qualitative leap, the students inquiry ability will be improved quickly.The extracurricular experiment smoothly can make a strong thirst for knowledge and students with different needs belongs and actual life, teaching theory and experiment combined to make them in a pleasant atmosphere actively corretly and acquire knowledge, enhance ability.Second, the fun experiment, stimulate students curiosity psychological and desire to exploreTeachers should be careful organization and design experiment content, the textbook knowledge with real life. When talking about ph indicator, for example, connectivity, can let students reveal their runescape legerdemain blood fingerprints, phenolphthalein sprayed on a piece of white paper to dry first, and then use hand touch point of caustic soda, press on the white paper will have a bloody hands, till the water (water against the dilute hydrochloric acid, white vinegar, etc.) turned colorless, in principle is phenolphthalein encounter alkali red encounter acid become colorless, mass annihilation is nonsense, let the students learn to distinguish between pseudoscience in their lives. Also the same with FeCl3 spray drying on yellow paper, and then use hand touch water against the colorless KSCN (water solution), there will be blood fingerprints appear on on toilet paper, the principle is Fe3 + binding reaction with the SCN - generated blood red substances. For example, when talking about physical properties of I2, let the students into several groups to do fingerprint identification experiment, pick up a clean, smooth white paper, force the piece of paper with finger press a few fingerprint, the sesame seeds a grain of iodine,www.nzz99.com www.xdzhang.com www.nyxydc.com in a test tube, then hang the white paper in the test tube (note the press have hand side do not stick on the wall), inserting rubber plug. Test tube containing iodine in the alcohol lamp flame above a low-grade fever, after waiting for iodine steam produced immediately stop heating, found that obvious personal note in the yellow fingerprint impression, then let the students understand the nature of I2 sublimation and easily soluble in organic solvents. Students with iodine test sausage bought in the supermarket in the starch content (I2 starch blue). This is not every class is to design, but at least toward this direction diligently, in the process of students hands-on operation can every tiny phenomena in the experiment to see clearly, it can better to mobilize students learning initiative, is advantageous to the students observing ability, thinking ability and the cultivation of ability.In short, in the chemical teaching, interesting and contact the actual life experiment is helpful to mobilize the classroom atmosphere, almost students can corretly to study and try to finish these interesting experiments, really pursue recreation, education with a new, able to create. Tried anything is easier to understand clearly to make this is used in this experiment and theory are more likely to inspire the students creativity, explore and imagination, and acquire knowledge, consolidate the knowledge in the fun, maybe after class the students will be interested to design more new content, new projects, and to validate, to test, boldly to complete their own ideas, in the experiment to obtain new knowledge, so as to improve the education quality of teaching.