初中物理的“压强”演示实验,不论按课本的方法做,或按一些资料讲的,在实验中将朝学生一面的砂槽改成用玻璃代替来观察,还是在海棉上加重物来做实验.均存在一些令人不尽满意的地方:①用砂槽做实验,砂不容易筛得很均匀,摩擦大,且受砂的干湿的影响,携带也较笨重,实验现象不够明显.②用砂做实验要在小钉凳上加较大的重物才有下降现象,观察不方便,③在海棉上加重物,因海棉只能有下陷现象,尽管也能观察到一些形变,但作为学生在侧面观察,效果也不理想.笔者受有关资料的启发,将该实验再进行改进,效果大有改善。 1.实验前准备①买一块洗澡用的海棉块(选厚大一些,气泡空大一些,平整而松软的为佳)在海棉的侧面用毛笔蘸 The “pressure” demonstration experiment of junior high school physics, whether it is done according to the textbook method or according to some information, will change the sand slot on the student’s side to glass instead of observing, or increase the weight on the sponge. Experiments. There are some unsatisfactory places: 1 The sand tank experiment, the sand is not easy to screen a very uniform, large friction, and affected by the wet and dry sand, carrying more cumbersome, the experimental phenomenon is not obvious. 2 It is necessary to add a heavy weight on the small nail stool to have a drop phenomenon when the sand is used as an experiment. It is inconvenient to observe it. 3 Heavy materials are added to the sponge. Because the sponge can only sink, although some deformation can be observed. However, as a student observes on the side, the effect is not ideal. The author was inspired by the relevant data, the experiment was further improved, and the effect was greatly improved. 1. Prepare before the experiment 1 Buy a piece of sponge used for bathing (choose thicker, larger air bubbles, flat and soft is better) with a brush on the side of the sponge.