涡漩

    　原理：涡漩是种复杂的三维流动（它一边作平面的二维旋转，一边又沿径向座标运动），能形成漏斗形旋转面，它具以下性质：

       a、漏斗形涡面上各点压力相同，故又称等压涡面。
       b、同一水平面上，水的旋转速度（切向速度）与半径成反比；半径小的地方流速高，导致压力低；半径大的地方流速低，导致压力高。
涡漩的中心部分流速高、压力低，越往外流速越低、压力越高。因此，涡漩具有向中心方向的抽吸作用。由此可见，为什么落入涡漩区域的物体很难逃离涡漩。
　　操作：观众可以从水盆中捞取小球，然后把小球放到吹球机中，小球沿着管道落入涡漩圆桶中，观众可以清楚的看到小球是如何被吸入漩涡中的。    

vortex

    　Principle: vortex is a complicated 3-dimension current (it do both 2-dimension rotating in horizontal and moving up and down in vertical)shapes like a funnel, which has following features:

　　a、 it has an equal pressure upon every point in the cap surface of the funnel, thus is named constant  pressure vortex surface.
　　b、 At the same level, the speed of water whirl has the inverse ratio with the radius; it flows with a high speed in areas with a small radius, which causes the pressure here low, And vice versa.
It has a high speed and low pressure in the center of the vortex, the more far from the center the more low speed and high pressure, which indicates that the vortex has a force of pushing toward the center. As a result, it is difficult for an object falling in vortex to escape.
　   Operation: the visitors fetch the small ball in the water and put it in the blowing machine. The ball falls into a barrel full of swirling water. After that, the visitors observe how the ball is absorbed in to the vortex.