“大气压测定”一节教材是在学生学习了液体压强的公式、连通器、大气压强等知识基础上进行的。实践证明,本节教材若按课文的论述进行教学,学生普遍对大气压测定的原理感到比较抽象、难理解。所以,在演示托里拆利实验测定大气压之前,教师可补充演示以下二个辅助实验,(作为过渡性实验)以帮助学生对托里拆利实验的理解。一、取两端开口的U形玻璃管一支(可用压强计玻璃管),在管内注入约一半红水,静止时,左右管液面一定相平(如图1)。问学生为什么?(学生即能回答:同种液体 The textbook “Measurement of Atmospheric Pressure” is based on students’ knowledge of liquid pressure formulas, connected devices, and atmospheric pressure. Practice has proved that if the teaching materials of this section are taught in accordance with the discourse of the text, students generally feel that the principle of atmospheric pressure measurement is relatively abstract and difficult to understand. Therefore, before demonstrating the atmospheric pressure of the Torridelli experiment, teachers can supplement the demonstration of the following two supplementary experiments (as a transitional experiment) to help students understand the Torridelli experiment. 1. Take one U-shaped glass tube with both ends open (available pressure gauge glass tube), and inject about half of the red water into the tube. When it is stationary, the liquid levels of the left and right tubes must be equal (Figure 1). Ask students why? (Students can answer: the same kind of liquid