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1 取一根长20cm左右,直径2cm左右的透明硬塑料管,上下端均用橡皮塞塞紧,在管的上端和靠近管底部处各钻两个小孔(图1)。实验时,往管里注满水,管的下端小孔
1 Take a hard plastic tube with a length of about 20 cm and a diameter of about 2 cm. Plug the upper and lower ends with rubber stoppers and drill two small holes at the upper end of the tube and near the bottom of the tube (Figure 1). During the experiment, fill the tube with water, the lower hole of the tube