我在教学《电从哪里来》(人教版自然义务教育教材第七册)中有这样一个片断:在指导学生自制电池过程中(按课本要求:在盛有碱水或醋的容器中插入锌片和铜片,再接上收音机上的小喇叭,使小喇叭发出声音),实验成功后,有个学生自行换接上一个小灯泡,小灯却不亮。 In my teaching “Where the Electricity Comes” (PEP Version 7), there is such a piece: During the process of guiding students to make their own batteries (according to the textbook requirement: insert in a container filled with alkali water or vinegar Zinc and copper, and then connected to a small speaker on the radio, the speaker makes a small sound), the experiment was successful, there is a student on their own replacement for a small light bulb, small light is not bright.