Michelle Pammer, age 7, of New Tripoli, Pa., for her question:

WHAT CAUSES A DOUBLE RAINBOW?

Double rainbows are not at all uncommon. When you see one inside the other, the inner rainbow is usually brighter and is called the primary bow. The fainter, outer bow is called the secondary rainbow, and it shows red  on the inside and violet on the outside. The primary bow has red on the outside and violet on the inside.

On seeing a primary rainbow, light from the sun enters a drop of rain at the top, is bent three times and then travels to the eye. With sight of a secondary bow, light enters the bottom of a drop of rain and is bent four times before it reaches the eye. You see two images because light comes to the eye at two different angles.