“真空中不能传声”是“声音的发生和传播”一节中的一个难点，目前尚无现成的仪器来演示验证。教师讲起来空洞，学生听起来抽象。为此，笔者设计制作了一种“真空不传声实验演示仪”。应用于教学中，取得了良好的效果。１ 仪器制作 取一支一次性大号医用注射器，先在其活塞上 “Can’t transmit sound in vacuum” is a difficult point in the section “Sounds Occurrence and Propagation”. There are no ready-made instruments to demonstrate. Teachers speak empty and students sound abstract. For this reason, the author designed and produced a “vacuum-free acoustic demonstration device.” Applied to teaching, achieved good results. 1 Instrument preparation Take a disposable large medical syringe, first on its piston