This surface is slightly more dense than the rest of the liquid. We notice this when we float a needle on the surface of a glass of water. Surface tension produces contraction forces in liquid films causing the free surfaces to assume a minimum area. Surface tension causes a free liquid to assume a spherical shape. Finally, liquids have the property of capillarity.
Capillarity is the elevation or depression of liquids in small diameter tubes.
Capillarity depends on both the cohesive and adhesive properties of the liquid. Liquids rise in capillary tubes they wet and are depressed in tubes they do not wet. Elevation or depression is inversely proportional to the diameter of the tube. The elevation or depression decreases as the temperature increases. The elevation or depression depends on the surface tension of the liquid.