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新人教版义务教育教科书(九年级物理),在第十四章《热机》一节中关于内能的利用演示实验中,将水加热至沸腾,试管口的橡胶塞受到水蒸气的压力而喷出,水蒸气的内能转化成塞子的动能.实验时,橡皮塞从试管喷出时会有热水随之溅出伤人,且塞子赛得太紧会使试管炸裂,塞不紧实验又不能成功,将橡皮塞换成软木塞仍存在此问题.笔者在教学中将该实验做
The newcomer’s compulsory education textbook (ninth grade physics), in the demonstration of the use of internal energy in the “Heat Engine” section of Chapter 14, heats the water to boiling, and the rubber plug of the test tube is exposed to the pressure of water vapor. The inner energy of water vapor can be converted into the kinetic energy of the plug. During the experiment, hot water will be splashed when the rubber plug is sprayed from the test tube. The tightness of the plug will cause the test tube to burst and the plug will not be tight. Can not succeed, replacing the rubber plug into a cork still has this problem. The author did the experiment in teaching