Why, if water always takes the shape of its container, does rain appear to bounce?

Answer 1

Raindrop falling; it has momentum.

It hits some OTHER water, in a puddle. Momentum keeps it going downwards. What follows it downwards is what was following it all the way: a wake of air.

So now a jet of air has buried a hole inside the water. Not a stable situation. Buoyancy forces accelerate the water nearby and cause it to pile into the hole from the sides and the bottom of the hole, so as to fill it up and restore equilibrium.

This water meets all its other brother bits of water piling in, and they all have momentum, which has got to go somewhere. Nothing with any mass at all can ever truly stop dead. It only has one direction available to it: UP. A little spout shoots up. It looks like it was the original water bouncing. It's not. It's a whole lot of other water that might contain a little bit of the original but will be mostly other stuff.

Water landing on dry surfaces does NOT "bounce", and that is why.

Answer 2

All of the H2O molecules in a drop of rain are attracted to each other by hydrogen bonds. These hydrogen bonds cause the molecules to "stick" together, creating a sort of surface tension. When rain first hits the ground, the surface tension of the rain drop has not yet broken, so the collective group of molecules appears to bounce away from the ground.

Answer 3

Because of gravity there is more down force on the drop so that when it hits a hard surface it will spread out. if was hitting a carpet or a soft surface the rain would be absorbed in to the surface instead of being forced out and flattened out!!

Answer 4

Because the force of the impact breaks apart the rain drop.

Answer 5

Because the impact of the droplet is great enough to make it splash before flatting itself to the surface.

Answer 6

Gravity creates the force that makes the splashing effect.