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为了加强教学直观性,使学生在实验过程中观察到明显的化学现象,获得比较深刻的印象,对统编教材初中化学里有关卤素的三个实验,提出如下的建议。 一、建议“碘的升华”和“氢氟酸的雕刻玻璃”采取边教边实验的方式进行教学。 1.碘的升华 教师课前准备好两端已经封口、中有少量碘片的玻管一支,随同酒精灯和火柴分发给学生(两人一组)。教师在讲解碘的物理性质时,先作出示范实验,再指导学生实验,让学生清楚地观察碘的物理状态和升华现象。
In order to enhance the intuitiveness of the teaching, students were observed to have obvious chemical phenomena in the course of the experiment and gained a relatively profound impression. The following recommendations were put forward for the three experiments on halogens in the junior high school chemistry textbook. I. It is recommended that “Iodine Sublimation” and “Hydrofluoric Acid Engraving Glass” be taught in a way that teaches while experimenting. 1. The sublimation of iodine The teacher prepares a glass tube with sealed iodine tablets and a small amount of iodine tablets in front of the class. It is distributed to students (two people) along with alcohol lamps and matches. When teachers explain the physical properties of iodine, they first make demonstration experiments, and then guide students to experiment so that students can clearly observe the physical state of iodine and sublimation phenomena.