功的原理是初中物理教学中的重点和难点之一,现就此知识点的教学谈点看法和做法。现行教材和人教社的实验教材,都是通过分析杠杆、滑轮等几种简单机械能省力或距离但不能省功的办法,得出功的原理的。而且教学参考书中强调,不能直接从实验中测出力和距离各物理量,只能利用杠杆平衡条件通过计算得出结论,否则将得不到功的原理,甚至连近 The principle of work is one of the key and difficult points in the teaching of junior high school physics. The current teaching materials and experimental teaching materials of the People’s Education Society are based on the analysis of leverage, pulleys and other simple mechanical energy saving or distance, but can not save the way to work out the principle of work. Furthermore, in the reference book for teaching, it is emphasized that the physical quantities of force and distance cannot be measured directly from the experiment, and only conclusions can be obtained through calculation using the condition of lever balance. Otherwise, the principle of no work can be obtained.