取一根直径约为1．5厘米的玻璃管，上端用塞子封闭，另找一个直径稍小于长玻璃管的小瓶（以小瓶能在长管内自由移动为宜）．实验时，先在长管内灌满水，将小瓶瓶口朝下插入长管内，管内水徐徐流下，小瓶不但不掉下来，反而渐渐上升，一直到长管的顶部为止．如图l．推动小瓶上升 Take a glass tube with a diameter of about 1.5 cm. Close the top end with a stopper. Look for a vial that is slightly smaller than the length of the glass tube (the vial can move freely within the long tube). During the experiment, the long tube was filled with water and the vial was inserted into the long tube downwards. The water in the tube was slowly flowing down. The vial not only did not fall, but gradually rose until it reached the top of the long tube. As shown in Figure l. Push the vial up