Raindrop Shapes on Fruit and Leaves
March 29, 2018
Photographer: Menashe Davidson
Summary Author: Menashe Davidson
The photos above were captured in my terrace garden at my home in Rishon LeZion, Israel, following a brief rain shower. The top photo shows drops on the fruit and leaves of a kumquat tree (Citrus japonica, family Rutaceae). Note that the water drops near the top of the fruit are flattened with an irregular shape. The mutual attraction of water molecules to each other gives water surface tension and helps create domed drops like these. When a rain event ends, the surface tension draws the domes into flattened dome shapes. However, drops on the bottom of the fruit are more spherical because of the effects of gravity, as are the clear, transparent drops on the tips of the green leaves, which here function as a lens, refracting light to produce inverted images of a tall building located some 250 ft (80 m) from the terrace.
The second photo shows water drops on the stem and leaves of a climber plant, Pandorea jasminoides (Variegated Bower, Vine family Bignoniaceae). Again, note the differences in drop shapes. For example, drops on the upper surface of the leaf at center are dome-shaped, the large drop on the bottom of the leaf is oblong. Photos taken on December 6, 2017.