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在课堂演示实验设计时,教师有时忽略了学生的感受,这不利于激发学生的学习兴趣。现谈两例九年级课堂演示实验的设计改进,愿与大家共同探讨。一、关于NaOH的性质在讲解NaOH的性质时,教师取1支小试管,然后加入适量水,让在前排就座的一个学生用手摸摸,加入NaOH少量,振荡,让学生观察,NaOH全部溶于水,又让刚才那个学生再用手摸摸试管,问:“有什么感觉?”那个学生吞吞吐吐。教师启发:“是不是感觉试管温度高了?”学生只好回答:“好像是。”下面的学生哄堂大笑。教师总结:NaOH极易溶于水,溶解时放出大量的热。整个实验过程中,学生处于被动地位,只能凭主观感觉去
When demonstrating the experimental design in the classroom, the teacher sometimes neglects the students ’feelings, which is not conducive to stimulating students’ interest in learning. We are now talking about the design improvement of two ninth-grade classroom demonstration experiments, and we are willing to discuss with you all. First, on the nature of NaOH In explaining the nature of NaOH, the teacher took a small test tube, and then add the appropriate amount of water, so that the front row of a student hand touch, add a small amount of NaOH, oscillation, so that students observe the NaOH All dissolved in water, let the student just touch the test tube again and asked: “What do you feel? ” That student dumbfounded. Inspired by the teacher: “Does it feel that the test tube temperature is high?” “The students had to answer: ” Seems to be. "The students below laughter. Teacher’s Summary: NaOH easily soluble in water, release a lot of heat when dissolved. Throughout the experiment, students in a passive position, only by subjective feeling to go