小学自然常识教材中关于液体表面存在张力的实验是这样做的：在一碗中放入适量水，手持一根缝衣针，轻轻地横放在碗内水面上，现象是针浮在水面。但该实验失败率很高，破坏了学习气氛，引起学生对知识的怀疑。我们在指导学生课外活动的教学实践中，采用下面的装置，演示液体表 Primary natural teaching textbook experiment on the existence of tension on the surface of the liquid is done: put a proper amount of water in a bowl, holding a needle, gently placed horizontally on the surface of the bowl, the phenomenon is the needle floating on the water . However, the high rate of failure of the experiment, undermined the learning atmosphere, arousing students' suspicion of knowledge. We teach students in extracurricular activities in the teaching practice, the use of the following device, demonstrate the liquid table