论文部分内容阅读
按高中物理第二册(甲种本)第99页图5—7的装置,来进行演示时,实验时间长,仪器多(用真空罩和电动抽气机),并且宜在实验室内进行.我们所用的方法,简单易行,装置如图1所示.实验时:在250毫升的平底烧瓶内装入热水,使水面接近瓶口.然后用胶塞塞 住,将30毫升(或50毫升)的医用针筒的针头插入瓶内,抽出瓶中的空气使瓶内气体压强减小到一定程度时,便可看到热水沸腾起来,这说明外部压强减小,水的沸点就降低.反之若再将抽去的气体重新压入,则可
According to the device in Figure 5-7 on page 99 of High School Physics Book 2 (Type A), the time for the experiment is long and the instrument is large (using a vacuum hood and an electric aspirator), and it should be performed in the laboratory. The method we used was simple and easy. The device was as shown in Figure 1. During the experiment: Fill a 250 ml flat-bottomed flask with hot water so that the water is close to the bottle. Then stopper it with a stopper and place 30 ml (or 50 When the needle of the medical syringe is inserted into the bottle and the air in the bottle is pulled down to a certain degree, the hot water boils up. This indicates that the external pressure is reduced and the boiling point of water is reduced. On the other hand, if the pumped gas is repressed,