Sheree Tillem, age 7, of Atlanta, Georgia, for her question:

What are crayons made of?

There are smooth, waxy crayons and dry, dusty crayons    and many other kinds. Naturally the people who make them don't tell us exactly how they do it. The recipes are trade secrets. But we know more or less what they use to make most of their different crayons. As a rule, they use one basic ingredient, a small amount of material to add the color and traces of several different materials to hold the crayon in shape and make it useable.

The basic ingredient in greasy crayons is some sort of wax, usually like the waxes they use to make candles. Some of these waxes come from the same petroleum oil that gives us gasoline. A very different main ingredient is used to make the dusty crayons we call pastels. Usually it is chalk. And chalk is made from the shells of tiny, tiny creatures that live in the sea.