<P> One drop equals 50 mm ^ 3, then 1 cubic centimetre = 20 drops </P> <P> Liquid forms drops because the liquid exhibits surface tension . </P> <P> A simple way to form a drop is to allow liquid to flow slowly from the lower end of a vertical tube of small diameter . The surface tension of the liquid causes the liquid to hang from the tube, forming a pendant . When the drop exceeds a certain size it is no longer stable and detaches itself . The falling liquid is also a drop held together by surface tension . </P> <P> In the pendant drop test, a drop of liquid is suspended from the end of a tube by surface tension . The force due to surface tension is proportional to the length of the boundary between the liquid and the tube, with the proportionality constant usually denoted γ (\ displaystyle \ gamma). Since the length of this boundary is the circumference of the tube, the force due to surface tension is given by </P>

The property of a liquid that causes small drops to be spherical is called