新编初中物理课本第二章第四节“做功和内能的改变”的实验1,是演示压燃棉花的传统实验。许多老师反映根本压燃不着,即使用乙醚浸过的棉花也不行。这个实验的成功关键是必须用硝化棉。只要用一点点硝化棉,一压立即点燃,且发出耀眼的光亮。每年实验前我都自己做点,现把硝化棉的制取过程介绍如下: The first experiment in the second chapter of the second edition of the junior middle school physics textbook, “The change of work and internal energy,” is a demonstration of the traditional experiment of compression-ignition cotton. Many teachers report that they cannot be ignited, that is, using cotton soaked in ether. The key to the success of this experiment is the necessity of using nitrocellulose. As long as a little bit of nitrocotton is used, a pressure is immediately ignited and a dazzling light shines. Before the experiment every year, I did my own thing. Now I will introduce the preparation process of nitrocellulose as follows: