改变物体的内能有两种方式--做功和热传递.热传递与大量的摩擦生热改变物体内能的例子,学生们凭经验知识不难理解.但对于压缩气体(对气体做功),气体内能增加;相反,气体膨胀对外做功,温度降低,学生们由于缺乏这方面的经验,理解起来存在很大 There are two ways to change the internal energy of an object - doing work and heat transfer. Heat transfer and a lot of friction heat to change the internal energy of an object. Students can understand it with experience and knowledge. But for compressed gas (work on gas), The gas internal energy increases; on the contrary, the gas expansion does external work, the temperature decreases, and the students have a lot of understanding due to lack of experience in this area.