我在初中物理教学中用杠杆对课本的两个演示实验做了一些改动，效果很好。现介绍如下： 一、 用初二物理课本所示装置做阿基米德原理实验，后面的学生往往看不清弹簧秤指针所指示的刻度。在初二总复习时，因学生已有杠杆及其平衡条件方面的知识，我用杠杆换下原实验中的弹簧秤 In the junior high school physics teaching, I made some changes to the two demonstration experiments of the textbooks with good results. Are introduced as follows: First, use the device shown in the second physics textbook Archimedes principle experiment, the students behind can not see clearly the scale indicated by the spring scale pointer. During the second grade review, I used the leverage to replace the spring scale in the original experiment because of the students’ knowledge of leverage and balance conditions.