Scientists say they now know why raindrops are many different sizes, and the reason is far simpler than they expected.

With high-speed cameras, a team of French researchers has shown how a single raindrop fragments, under air resistance, into a scattered array of different-sized droplets.

Prior to this, scientists thought that raindrops smashed into each other as they fell from clouds, and that these collisions produced the range of drop sizes.

Footage courtesy of Emmanuel Villermaux, Aix-Marseille University