论文部分内容阅读
人教版《物理》八年级上册第三章第三节《汽化和液化》的《科学世界》中提到:水的沸点与大气压强有关,气压越低,水的沸点也就越低。直观演示水的沸点与大气压的关系,对教师教学和学生理解、掌握水的沸点与大气压的关系会很有帮助。一、传统演示实验的不足演示水的沸点与大气压的关系,没有专门演示仪,传统演示实验是:(1)水沸腾后停止加热,水停止沸腾,用冷水浇盛有适量开水的瓶底,水重新沸腾,如图1所示;(2)水沸腾后停止加热,水停止沸腾,用抽气筒抽气,水重新沸腾,如图2所示。其不足之外是:
People’s Education Edition “Physics” eighth grade third chapter third section third “vaporization and liquefaction,” “Science World” mentioned: the boiling point of water and atmospheric pressure, the lower the pressure, the lower the boiling point of water. Intuitive demonstration of the relationship between the boiling point of water and atmospheric pressure on the teaching of teachers and students to understand and master the boiling point of water and atmospheric pressure will be helpful. First, the lack of demonstration of traditional demonstration Demonstration of the relationship between the boiling point of water and atmospheric pressure, there is no special demonstration instrument, the traditional demonstration experiment is: (1) to stop heating after boiling water, water to stop boiling, Water boils again, as shown in Fig. 1; (2) stop heating after the water boils, the water stops boiling, draw the gas with the gas pump, the water reboils, as shown in Fig. 2. Its shortcomings are: