Ask Jimmy and the Bug

Jimmy and the Bug
there is a picture of Jimmy, catching a ball.

Hey Bug! Jaal M. from Costa Rica asks: “If the clouds are made of water why are they white?”

What a cirrus question!

there is a drawing of Bug.
There is a picture of Bug with a prism.

Clouds are white for the same reason the sky is blue—because of what happens to sunlight. Sunlight is really a combination of different lights in all the colors of a rainbow—red, orange, yellow, green, blue, indigo, and violet. We can see these colors if the light gets broken up, for example, by a prism. But we see all these colors together as white light.

On its way to Earth, sunlight runs into all kinds of little particles, including air molecules, dust, pollution, water droplets, and ice crystals. These particles scatter the light in different directions, but the different types of particles don't scatter light the same way.

There is a picture of Bug and Jimmy float in the clouds.
There is a picture of Bug.

The tiny molecules that make up the Earth's atmosphere scatter the blue light best. Most of the sun's rays reach the ground as white light, but some of the blue light gets scattered in all directions in the sky, so no matter where you look the sky appears blue. The large water droplets or ice crystals that make up clouds scatter all the colors of light equally, so clouds appear white.

Jimmy tries to take a cloud home in a bottle.

Jimmy holds a bottle with a small cloud in it.

Activity

  1. What is a rainbow?
    [anno: A rainbow is sunlight that has been broken into its separate colors.]
  2. Why is there no stripe of white in a rainbow?
    [anno: There is no stripe of white in a rainbow because white is created when all the colors are blended together. In a rainbow, the colors have been separated.]
  3. Colored lights have many uses. Some colored lights are important for public safety. Traffic lights, for instance, use red, yellow, and green lights to direct traffic. Other colored lights, such as theater lights, are used to create a mood. Think of another example of a colored light. What is the light used for? Write a few sentences about how the light is used, and why lights of different colors are important.
    [anno: Answers will vary.]