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设计背景传统的“做功改变物体内能”实验是利用空气压缩引火仪完成的,操作起来有一定难度:硝棉太多,不容易压燃;硝棉太少,压燃现象短暂,不利于学生观察,并且用力压缩空气时一次点燃硝棉不易成功.而白磷的燃点只有40℃,通过弯折铁丝做功使铁丝内能增加、温度升高,达到或超过白磷的燃点,从而能够方便地点燃白磷,现象剧烈,效果非常明显.实验目的探究做功能否改变物体的内能.
Design Background The traditional “doing work to change the internal energy of the object” experiment is done using an air compression pilot instrument. There is a certain degree of difficulty in operation: too much nitramide is not easy to ignite; there is too little nitrocellulose and the phenomenon of compression ignition is short. It is easy for students to observe, and it is not easy to ignite nitrate once when the air is compressed. The white phosphorus has a burning point of only 40°C. By bending the wire, the inner wire can increase and the temperature rises, reaching or exceeding the ignition point of white phosphorus. Phosphorus ignited, the phenomenon is fierce, the effect is very obvious. The purpose of the experiment to explore whether the function of changing the internal energy of the object.