Some Considerations on the Process of Penetration of Liquids into Capillary Tubes

For obtaining a more exact kinetic description of the capillary penetration of liquids, the usual equation of motion of liquids in capillary tubes was modified by considering the change of contact angle between the capillary wall and the liquid surface. Using the derived kinetic equation, the penetrating rate of water into glass capillary tubes and also the rate of molten copper into the iron capillary tubes were directly computed after the Runge-Kutta method. The calculated relation between the rising height of liquid in the capillary tube and the time agrees well with the experimental result, and the intensive effect of the time dependent contact angle on the rising process of liquids into the capillary tubes was confirmed.