A drop enough to explain the behavior of rain

2009/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Fisika
• Hidrologia

To know the distribution of water drops in torrential rains, two scientists from the French University of Aix-Marselle have observed the fall of water drops. In fact, they have seen that raindroplets that come out of a single drop have the same characteristics as those that can be seen in raincoats.

They drop the drops of a tap individually and record the fall to see what happens to the drops of water. As the speed increases, they have seen that the shape of the drop changes: first it adopts the shape of the crepes, that is, it puts on a handkerchief, then it has the shape of a pot with the butt high and finally explodes and is divided into several droplets.

This is because as speed is reached the air increases its resistance to drops. From a given moment, the air resistance is superior to the internal cohesion force of the thick drops of water, breaking the thick drops.

Something similar happens with rainwater when it falls in the clouds. The drops break and the droplets come out of those thick drops.