Sky Blue, and an Art and Science Project
Sky blue is a beautiful color, used often in decorating. It makes a room brighter, more inviting and more cheerful while still providing a relaxed atmosphere. Thus it may be found in many hospitals and doctor's offices. And in our laundry room. When dressing a baby, reaching for this color will automatically make known that your baby is a boy, although this has not always been the case. Early in the 20th century, pink was for boys and blue for girls. Pink was viewed as a muted version of the fiery red, and hence more suitable for boys, while blue was the daintier of the colors. The roles reversed in World War II, some speculate because Hitler used pink triangles to mark homosexuals in the concentration camps.

Because it is so closely identified with the sky, it is symbolic as well. A picture of the sky, like the one here, can easily be related to many well-known sayings: the sky's the limit, reach for the sky, sky high, or even pie in the sky. It emphasizes opportunity and limitlessness. As we go forth into the wild blue yonder, adventure and honor await. At least one University has sky blue as one of its colors, and quite a fascinating story to go along with it. Maize and blue have always been the colors of the University of Michigan. But which shade? Memories fade in time, as do colors. And it took more than one attempt to reach today's standard.

The sky is blue because of Rayleigh scattering. As light passes through the atmosphere, the longer wavelengths, such as red and yellow, pass through relatively straight. The molecules absorb the shorter wavelengths, including blue. This light is then scattered in all directions. Thus, the sky looks blue in all directions. Nearer the horizon, however, the light must pass through more atmosphere which scatters the light even more. This is why the horizon looks pale in comparison to the deep sky blue above. In space, there are few molecules and hence little scattering. Thus when in space, the "sky" appears black and the sun white.

To demonstrate why the sky is blue, try this experiment.

Materials needed: A clear glass container (rather large), a flashlight, milk

Fill the container with water and a few drops of milk. Stir the milk in well. Make sure the water is "milky" and hard to see through.

Shine the flashlight through the liquid. Look at the liquid from above. Is there any change in color? Try looking stratight through the glass at the light source. Now is there a change in color?

If it doesn't work, try adding a few more drops of milk, but you should note that it looks normal from above, with a color change while looking directly through the liquid at the flashlight. This is due to the Rayleigh scattering.

For an art project with sky blue, try this activity.

Go on a scavenger hunt for items that are sky blue and photograph them. Carefully cut them out and lay them in a bowl.

Draw a horizon line on a green sheet of paper.

Carefully glue your collage of blue pictures above the horizon line for the sky.

You can then cut out other pictures you have drawn or out of magazines to make your picture of the outdoors.

For more studies in color, check this entry.
Look here if you'd like to join Happy Things' Year of Color.

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