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在《燃烧与灭火》一课中,为了使学生理解燃烧需要达到一定的温度,我设计了这样的实验: 在铁架台上固定一块圆形薄铜片(铜的导热性能较好),然后在圆铜片的某一半径上由中心依次向外排列三根火柴(如下图),用酒精灯对准圆铜片的中心加热,让学生观察哪一根火柴最先燃烧。 师:在实验中,你发现哪一根火柴最先燃烧起来? 生:放在中间的火柴最先燃烧,放在最外边的火柴过了一段时间才燃烧起来。 师:点燃酒精灯后,三根火柴是不是都会受热?为什么?
In the lesson of “Combustion and Extinguishing Fire”, I designed the experiment to fix the temperature of the combustion and let the students know that a round thin copper plate (better thermal conductivity of copper) was fixed on the iron platform, A certain radius of the round copper from the center followed by the arrangement of three matches (see below), with alcohol lamp alignment center of round copper heating, let the students observe which match the first burning. Teacher: In the experiment, which one of the matches you found was the first to burn? Health: The match that was placed in the middle burned first, and the match on the outermost flames came to light after a while. Teacher: After ignite the alcohol lamp, three matches are not heated? Why?