David Feick, age 10, of Pittsburgh, Pennsylvania, for his question:

How do they make soap?

Our busy pioneer ancestors made their own soap, mostly from waste fats and lye. Naturally this bubbly stuff was not related to our fancy chemical detergents. Neither was it a menace to the environment. Nature can cope with waste soapy water because its molecules can be broken apart and recycled as useful new ingredients. Modern detergents pollute our streams and soil because the earth has trouble recycling their stubborn molecules.

Most likely your great great grandmother made most of her own soap in a large metal pot. For weeks she saved the used bacon grease and every scrap of waste fat. Chances are, the big metal pot was kept outdoors in the backyard, set over a grate to hold a fire. When soap making day came around, the greasy fats were put into the pot with some water and a helping of a strong alkaline ingredient. The caustic alkai may have been lye.

When the fire boiled the mixture, a chemical miracle occured. The fats and the strong alkali changed themselves into, of all things, a batch of soupy soap. This was sifted and strained and left to set solid. Then it was chopped into handsized chunks. When mixed with water, its foamy bubbles did a fine job on the laundry and performed all the other household cleaning duties. Maybe the family bought a few bars of fancy face