初三物理课本中,在《对流》一节,安排了水的对流实验,学生不容易看清楚。本人认为实验中应该选用不溶于水的物质来做。我在教学这节内容时,用红粉笔末来代替高锰酸晶粒。加热时由于水的流动,粉笔末跟着水流一起流动。由于粉笔末不溶于水,因此实验现象就 In the third grade physics textbook, the convection experiment of water was arranged in the section of “Convection” and it was not easy for students to see clearly. I think that the experiment should use water-insoluble substances. When I was teaching this section, I used red chalk to replace the permanganate crystals. As the water flows when heated, the chalk flows with the water. Because chalk is insoluble in water, experimental phenomena are