Tell why small droplets of water on an oily surface are almost spherical.

When the water droplets are placed in oily surface, oil being non-polar, thus there will not be adhesive force between water and oil.

Thus, surface tension is the factor which is responsible for shape of the water droplets to be spherical. The water molecules are pulled into the spherical shape by the action of the cohesive forces which is acting on the surface layer. As, the medium is totally different outside, the water molecules tend to get the minimum area and thus, forming spherical droplets.