Page 46 - Reading Success B4

The sky is usually blue. Sometimes, it changes colors as the sun rises or sets.
Sometimes, the sky is clear and bright. Other times, the sky is covered by clouds.

Do you know why there are clouds in the sky? Do you know what clouds are
made of, and where they come from? Clouds are actually composed of very small

drops of water. These small drops of water are almost frozen in the air. We can
see these drops of water when billions of them are close together. That is

because they form clouds. Clouds are usually white in color. They are white when
the drops of water are very close to each other. However, clouds can have

different colors, too. When the sky changes colors because of the Sun, the clouds
also change colors. This is because clouds are white. Clouds can also change

colors even if the sky does not. Clouds can become gray. Sometimes, they are
very dark. This happens when the drops of water are very far from each other.

That only means they have become bigger and heavier.
There are different types of clouds. The major types are cumulus , stratus ,

cirrus, and nimbus. They are different in how they look, and how high they are in
the sky. Cirrus clouds are the clouds that stay in the highest level. They are also

very thin. Nimbus clouds are the darkest and lowest clouds. Nimbus clouds are
also called rain clouds. That is because nimbus clouds are composed of big and

heavy drops of water. This means they are ready to fall to the ground in the form
of rain.

Main Idea

What is the main idea of this story?

a. the composition of clouds and the different types

b. the study of the clouds and the atmosphere
c. the makeup of the sky and water vapor

d. the structure of cumulus and nimbus clouds

48_Reading Success B 4