In a simple way, we say that it is due to the surface tension. There are some Facts for understanding surface tension:
According to the surface tension :
Bubbles (hollow drop) Surface tension acts to minimize the surface (radius of the spherical shell of liquid), but is opposed by the pressure of vapor. Surface tension enables insects to walk on the surface of the water.
- High intermolecular forces = greater surface tension
- Cohesion causes water to form drops
- surface tension causes them to be nearly spherical
- adhesion keeps the drops in place
- intermolecular attraction forces act to minimize the surface area of liquid
- Geometric shape w/smallest ratio of surface area to volume is the sphere
- Surface molecules are drawn inward and area of the surface of the liquid reduced
- : small quantities of liquid form spherical drops
- As drops get larger, weight deforms them into a typical tear shape.