Asked by: Randall Barfield, USA
The terminal velocity of a raindrop depends on its size. The water droplets in clouds are only around 20 microns across and fall at only 1cm per second or so. This is normally balanced by updraughts, so the cloud stays in the sky. The droplets in a light shower are 100 times larger and fall at 6.5m/s or about 22.5km/h (14mph). The largest possible raindrops are 5mm across and hit the ground at 32km/h (20mph).
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.