编者：学好初中物理第一册第二章《分子运动论内能》关键是物体的内能是指分子无规则运动的动能和由它们相对位置所决定的势能的总和．对于内能概念的理解应从下列两个方面下功夫：1．理历改变物体内能的两种方法——做功和热传递（I）做功做功是改变物体内能的物理方法之一，? Editor’s Note: The key to learning the second chapter of the junior high school physics book “Inner energy of molecular movement theory” is that the internal energy of an object is the sum of the kinetic energy of the molecules’ random movement and the potential energy determined by their relative positions. The understanding of the concept of internal energy should be made from the following two aspects: 1. Two ways to change the internal energy of an object: doing work and heat transfer (I) Doing work is one of the physical methods to change the internal energy of an object.