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一、从直观教学手段中形成化学概念许多学生在学习化学中发现很多基本概念特别是微观世界,摸不到,看不见,难以理解.因此教师在教学中可以利用各种直观手段,尽量做到抽象问题具体化,复杂问题简单化.让学生看得真切,印象深刻,易于记忆.比如在教学初三化学第一单元课题1的“物理变化”、“化学变化”概念时,教师演示实验:(1)加热试管中的水至沸腾;(2)在研钵中研磨硫酸铜晶体;(3)在试管中加热硫酸铜晶体;(4)往硫酸铜溶液中滴加氢氧化钠溶液.学生观察实验现象后,
First, the formation of chemical concepts from the visual teaching means Many students found many basic concepts in learning chemistry, especially the micro-world, can not touch, invisible, difficult to understand.So teachers can use a variety of visual means in teaching, try to be abstract For example, in the first unit of teaching chemistry first unit subject 1 “physical change ”, “chemical change ” concept, the teacher Demonstration experiment: (1) heating the water in the test tube to boiling; (2) grinding the copper sulfate crystals in the mortar; (3) heating the copper sulfate crystals in the test tube; (4) adding sodium hydroxide Solution. Students observe the experimental phenomenon,