目前关于先讲杠杆还是先讲滑轮这一问题,意见还不一致。按课本次序是将滑轮放在前面讲授。但从我们多次的教学实践中体会到,还是先讲杠杆较好,因为:1.滑轮实际上是杠杆的一种变形。先讲杠杆,利用杠杆的原理去分析滑轮,可以使学生对滑轮获得较透彻的理解,从而提高滑轮的教学效果。如果先讲滑轮,就不能利用杠杆的原理去解释滑轮,讲解时,只能通过实验的方法得出定滑轮和动滑轮的基本性质(定滑轮不省力也不省功,但能改变力的方向;动滑轮能省一半力,但不能省功)。这样虽然也能说明问题,然而 At present, there are still inconsistent opinions on the issue of first talking about leverage or talking about pulleys. In the order of textbooks, we put the pulleys on the front to teach. However, from our many teaching practice experience, it is better to talk about leverage first, because: 1. The pulley is actually a deformation of the lever. Firstly, leveraging leverage to analyze the pulleys using the principle of leverage can enable students to gain a more thorough understanding of the pulleys, thereby improving the teaching effectiveness of the pulleys. If you first talk about the pulley, you can not use the principle of the lever to explain the pulley. When explaining, the basic properties of the fixed pulley and the moving pulley can only be obtained through experimental methods (the fixed pulley does not save energy or work, but it can change the direction of the force; The moving pulley can save half the force, but it cannot save work.) Although this can also explain the problem, however,