Are raindrops tear-shaped?
I certainly thought so when I embarked on an undergraduate experiment into the refraction of light through water. But as I illuminated a stream of drops, arcing through the air in my laboratory, I saw not teardrops but perfect spheres. Not, it turned out, a ground-breaking scientific discovery, but, as a naïve student, this was rather unexpected.
When water first condenses from a gas into a liquid, the tiny water droplets in clouds are indeed spherical.
But as the droplet gets larger and larger, gravity takes effect and it starts its descent to earth. Accelerating towards the ground, the sphere gets squashed by the air resistance it encounters head-on. The result: not a sad tear-drop of rain that lands on our heads, but actually something more akin to the top half of a hamburger!
Food for thought the next time the heavens open.