Which of the following property of water can be used to explain the spherical shape of rain droplets?
(a) Viscosity (b) Surface tension
(c) Critical phenomena (d) Pressure
Answer: (b) Surface tension
The spherical shape of rain droplets is due to surface tension. The lowest energy state of a liquid will be when the surface area is minimum. Surface tension tries to decrease the surface area of the liquid to the minimum. The rain droplets are spherical because for a given volume, a sphere has minimum surface area.