Typical values of capillary rise are

1. Capillary rise is approximately 4.5 mm for water in a glass tube of 5 mm diameter.

2. Capillary depression is approximately - 1.5 mm (depression) for mercury in the same tube.

Capillary action causes a serious source of error in reading the levels of the liquid in small pressure measuring tubes. Therefore the diameter of the measuring tubes should be large enough so that errors due to the capillary rise should be very less. Besides this, capillary action causes the movement of liquids to penetrate cracks even when there is no significant pressure difference acting to move the fluids in to the cracks.

In figure (Fig : L - 3.6), a two-dimensional model for the capillary rise of a liquid in a crack width, b, is illustrated. The height of the capillary rise can also be computed by equating force balance as explained in the previous section.