George Coates, age 8, of Boise, Idaho, for is question;

What are clouds made of?

You might think that clouds are made of solid material. As they drift along, they hide the sun and cast shadows on the ground. This one looks as though it were; made of cotton, that one of ice cream. Those small curly clouds seem to be made of feathers and those long dark streamers look just like silken scarfs.

Actually, clouds are not made of cotton, feathers, silk or ice cream. They are not made of solid material at all. You know this if you have ever becn inside a cloud. And, chances are, you have. For a mist of fog is made of cloud material. A fog is really a cloud taking a rest on the ground. So, when you walk through a fog you are walking right through the misty stuff that makes a cloud.

This material is very like the frothy white steam that floats away from a kettle of boiling water. It is made of little droplets of water, so small that they can float in the air. It may take 10,000 to 100,000 of these droplets to measure one inch. And in a cloud they are scattered so that there is plenty of space between them. If all the droplets in a fair sized white cotton type cloud were squeezed together, they would make about a tumbler full of water.

Some clouds fly high where it is cold. Instead of droplets of water, these clouds are made of fragments of ice. Such clouds are very white and usually small. They are the curly feather clouds we see floating aloft. These icy whisps may be flying six miles above the ground.

When it gets ready to rain, a cloud changes color. Its droplets are bunching together in raindrops. Countless droplets go to make one raindrop. The raindrops in the cloud are between us and the sun and each is big enough to cast a little shadow. This is what makes a rain cloud look dark and glowering.

The rain falls when the drops are too big to float in the air. The rain water falls on the earth and the plants, animals and ourselves use up what we need. The rest sinks into the earth and runs into the rivers to the sea. Then out comes the sun with its warm, smiling face,

It dries and evaporates water from the seas, the lakes and the damp ground. This water turns into vapor which is an invisible gas. The vapor joins the other gases of the air and floats aloft. Up there it cools and turns into those tiny droplets of water. It becomes a cloud, floating and drifting in the wind.

Sooner or later, the cloud becomes heavy with raindrops. It sinks low and sheds its water back down again on the earth. Meantime the sun is drying up more water which becomes vapor. This vapor will form clouds which will also shed more rain.