在物理教学中,要想提高教学效果,教师必须做好课堂演示实验。因此,提高演示实验效果尤其重要。演示效果基本包括两个方面:一是保证实验成功;二是要有足够的可见度。笔者在提高演示可见度方面做了一些探索,取得了较好的效果。一、变小为大例如,在做“焦耳定律”一节的“探究焦耳定律的实验”中,比较煤油在玻璃管中上升的情况,由于玻璃管较细,不易看清,因此笔者做了如下处理,使后排的学生也能看清楚:如图1所示,一是在煤油中滴 In physics teaching, in order to improve teaching effectiveness, teachers must do well in classroom demonstration experiments. Therefore, it is particularly important to improve the effectiveness of demonstration experiments. The demonstration basically includes two aspects: one is to ensure the success of the experiment; the other is to have enough visibility. The author has made some explorations in improving the visibility of the demonstration and achieved good results. First, to become smaller. For example, in the “Joule’s Law experiment” in the section “Joule’s Law”, comparing the rise of kerosene in a glass tube, as the glass tube is thinner, it is not easy to see. Therefore, the author did the following processing so that the students in the back row can also see clearly: As shown in Figure 1, one drops in kerosene.