Joan Nassol age 10., of Brooklyn. N. Y.,, for her`‑'question:

How do the clouds get water in them?

Have you ever helped Mother hang out the wet laundry? A few hours later you are not surprised to find it all dry, The moisture has gone. It has evaporated into the air, It has broken into particles so tiny that the liquid water has turned into gas ‑ water vapor.

Evaporation goes on all the time, The thirsty air soaks up all the water it can. It dries up the puddles, It evaporates water from the sea, the rivers, lakes and streams, There are always tons of it in the air.

Sometimes the thirsty air gets too full of water vapor. This happens when the air cools, for warm air can hold more vapor than cool air, So warm air full of vapor must give some of it up when it becomes cool,

The air high up is cooler than that close to the ground. Also, warm air tends to rise.  When it gets aloft it is cooled. If it had a full load of vapor now is the time to unload, It unloads the vapor back into tiny, tiny droplets of water, This is the filmy, misty stuff of which clouds are made, At some time these tiny droplets will gel into big raindrops, Too heavy to fly they will fall to earth, Some of the water will be evaporated and the cloud story will start all over again.