Scott Horn, age 9, of Bartlesvilie, Okla. For his question:
How can clouds stay in the sky?
On a frosty morning, you can sometimes see for yourself how this magic works. Fill your lungs and then puff. If the weather is just right, you can see your breath hanging in the air like a misty fog. The air gathered moisture from your lungs. When you breathed out, this moisture became drops of water fine enough to hang in the air and make a little cloud.
A fluffy cloud is made of water. And water falls to the ground because it is heavier than the air. The water in a cloud may weigh as much as 20 houses, yet it floats on high like a flying carpet. This is because all that water is divided into fine droplets light enough to hang in the air.
Chances are, a cloud was born high above the ground. It was born because the air is thirsty. The air drinks up water from the seas and rivers, from the lakes and even from the wet laundry on the line. All this water evaporates and becomes gas vapor. If the air is warm, it rises aloft with its load of vapor.
When the warm air rises a few miles, it becomes cool. Then it must get rid of some of its vapor. The gasy water vapor is changed into droplets of liquid water. The fine droplets hang there in a frothy mist of light foam. A cloud is born a mile, or maybe five miles above the ground.
In the newborn cloud, one of the big droplets could swallow thousands of the smaiiest dropie'ts. Yet i.t would take hundreds of the big droplets to cover the head of a pin. There is plenty of space in the cloud. Between one droplet and the rest there is room for at least ten more droplets. The breezes soon blow the misty cloud across the sky. Just as the frothy flying carpet drifts along, it slowly sinks.
Ths lightest cloud is wads of the finest droplets. In a day and a night, it may sink down only a yard. Medium droplets sink a yard. In 30 seconds and big droplets sink a, yard every second. As it floats along, slowly sinking, a cloud may change. Its droplets may gel together and form big drops of water too heavy to float. Then down tumbles the rain.
In a sizeable cloud, there’s may be 100,000 tons of water. All this water is divided into miniature droplets small enough to hang in the air. Suppose you trapped a roomful of misty cloud and squeezed all the tiny droplets together. You would hays enough liquid water to fill perhaps two or three thimbles. But a cloud may be ten miles long and five miles deep with enough mist to fill all the rooms in a city.