It has been noticed the great difficlty of the liquid emergence from the top of the capillary tube. So it is recommended to insert a hollow thin string through a very small hole that is made at the top side of each capillary tube. Then all strings are collected a bove the fins, so the liquid drops fall down and cause the fins to rotate as shown in figure (b). Experiments mdicate that the magnitude of the capillary effect, h,is a function of the following:- 1- the liquid density(l):- it is inversely proportional to the capillary effect. 2- the temperature (t):- it is directly proportional to the capillary effect. 3- the tube diameter (d):- it is inversely proportional to the capillary effect. 4- the pressure (p) and the kinematic viscosty ( v):- the capillary effect is divectly proportional to the pressure and the kinematic viscosity.
