Ann Spatz, age 10, of Little Rock, Ark., for her question:

WHAT MAKES A SHADOW?

A shadow is the darkness that is cast when light shines on an opaque or nontransparent object. The shadow falls from the side opposite the source of the light.

Shadows fall from trees and buildings and also from our bodies.

The light of the sun also causes the earth to throw a huge shadow into space. The moon is darkened., or eclipsed, when this shadow hits the moon.

Shadows on earth are not completely black, as they are on the moon or in space. The atmosphere scatters some light, and this light lightens the shadows.

When light comes evenly from many different directions, as on a hazy day, shadows are not cast.