《热空气》一课涉及到“纸蛇”的演示实验。我们看了许多教师做课,制作的“纸蛇”演示往往不尽人意,做实验时,不是纸蛇旋转的速度比较慢,就是旋转的圈数少,或转几圈就停止了,实验效果难以激发学生的学习积极性。要想使纸蛇旋转的速度更快,归纳起来有以下几个方面:1.纸张的选择: The lesson of “hot air” relates to the experiment of “Paper Snake”. We read a lot of teachers to do the lesson, the production of “paper snake” demo is often unsatisfactory, when doing experiments, not paper snake rotation speed is slower, is the rotation of the small number of laps, or turn a few laps stopped, the experimental results Difficult to stimulate students' enthusiasm for learning. To make paper snake spin faster, summed up in the following areas: 1. Paper choices: