在初中生物教学中,要形成生物概念和认识生物规律,一般要有一定的感性知识作基础,而符合生物教学需要的感性素材大多由课堂上的演示实验得到。选择好并成功地完成一个演示实验,不仅能为学生学习生物知识提供符合认识规律的环境,有利于教师的讲授和学生的学习,而且还能培养学生的观察能力、思维能力,活跃课堂气氛,激发其求知欲。因此,提高演示实验的效果,是上好生物课的关键,要加强演示实验的效果,使之能较好地 In junior biology teaching, biological concepts and biological rules should be formed. Generally speaking, there should be some basic knowledge of perceptual knowledge, while most of the emotional materials that meet the needs of biological teaching are mostly obtained from experiments in the classroom. Select and successfully complete a demonstration experiment, not only for students to learn biological knowledge to meet the law of cognition of the environment is conducive to the teaching of teachers and students to learn, but also to develop students’ observation ability, thinking ability, active classroom atmosphere, Stimulate their curiosity. Therefore, to improve the effectiveness of demonstration experiments is the key to improving biology teaching so as to make it better to demonstrate experiments