Tami Tomlinson, age 9, of Newport News, Va., for her question:

WHY IS THE SKY BLUE?

This magic is performed by the sunbeams, as they dance in the air above our heads. The air is made of mini‑fragments called molecules‑‑and it reaches up for hundreds of miles. The sunbeams come dashing toward us from the sun, which is millions of miles out in space.

On their way down to the earth, the sunbeams must come through a thick layer of the airy atmosphere. And the air molecules play tricks on them. The sunbeams are actually bundles of rays, like threads of rainbow colors. The bitsy air molecules separate the blue rays from the mixture‑‑and scatter them around to color the daytime sky. At dawn and sunset, when the sun is low in the sky, the air molecules separate more of the colored rays, then the sky glows with reds, golds and other gorgeous rainbow colors.