Look at the lake receiving water from the sky. Up there, water begins as a vapour, becomes drops, which grow, become heavy and fall. And then they dissolve into each other again, but heavier, as befits their newer, lower location.
It’s great to watch! It’s all one drop at a time at this stage, and then each drop gives up its energy to become one with the others.
In these images, you are looking at the boundary between water and air. It’s not exactly non-porous!
Beautifully enough, the pressure that held the water up in the air and the pressure that brought it down, are matched by the pressure of the lake, which joins all the water molecules, new and old, together. Pressure also brings fish from the bottom of the lake to the surface, and lifts the lake into the air.
When the pressure changes, when the lake strikes the mountains, for example and the heat of the valleys to the south east push it up high, it will fall back down on our heads.
The sky is just this, a place in which the lake goes walking, as we do within it as well.