Kathy Sennett, age 10, of San Mateo,Calif., for her question:

How are rainbows made?

Rainbows are magic tricks done with beams of light and tiny mirrors. The light is provided by sunbeams; the mirrors are falling raindrops. To make it work, the stage must be set just right. The sun is fairly low in the sky, and on the opposite side of the sky there is a weeping cloud. The sunbeams strike the falling raindrops. The glassy raindrops separate the' the beam of light into separate bands of color. This is possible because ordinary light is actually a blend of all the colors of the rainbow. When the colored threads are separated, a gorgeous rainbow arches over the sky.