众所周知,化学是一门以实验为基础的科学。实验教学不仅能提供给学生认识化学规律的感性材料,而且还能培养学生的观察能力、思维能力和实验技能。教师要积极地创造条件,强化实验教学。特别是教师在演示实验时要经常变换教学方式,既能使学生掌握实验知识,又能调动学生的思维,还能活跃课堂气氛,可以收 As we all know, chemistry is an experiment-based science. Experimental teaching can not only provide students with the understanding of the chemical laws of the perceptual material, but also to develop students' observation skills, thinking skills and experimental skills. Teachers should actively create conditions and strengthen experimental teaching. In particular, teachers should constantly change their teaching methods when demonstrating experiments, which not only enable students to master experimental knowledge, but also mobilize students' thinking. They can also activate the classroom atmosphere and can accept