Beth Morrell, age 11, of Winnipeg, P;anitoba, Canada, for her question:

How do they make fabrics from petroleum?

The five main ingredients are simple chemicals, separated from the bewildering assortment of hydrocarbons in petroleum. The recipes for making them into synthetic fabrics may remind you of a cookbook. However, they require elaborate chemical processes and fantastic appliances for creating enormous heat, pressure and even vacuums. And naturally each synthetic fabric calls for its own precise recipe.

Hydrocarbons are hydropen carbon compounds, created by once living cells. There are hundreds of these chemicals in dark, syrupy petroleum and an oil refinery separates them into groups, or fractions. Benzene, one of the five major ingredients for making synthetic fabrics, is a clear tangy liquid extracted from a gasoline fraction. Methane and ethylene, butylene and propylene are four colorless gases taken from a naphtha mixture.

These major ingredients have small molecules. Elaborate chemical processes are used to remodel them, usually into ring shapes. These small units are called monomers. They are polymerized, or treated to cling together in long chain molecules called polymers.  The chemical brew may be heated, pressurized or treated in a vacuum. At various stages, an atom may be added to each unit, or subtracted. Catalysts are added to provoke the desired chemical reactions.

There are variations for producing nylons with different qualities. But the basic nylon formula begins with mixing an acid and an alkaline ingredient. Their opposite particles unite in pairs and form lamer molecules of nylon salt. Chemical drama occurs when this brew is put into a vacuum and heated to 500 degrees Fahrenheit.

Atoms of hydrogen and oxygen free themselves and become water. The former salt molecules become rings of 22 hydrogen and 12 oxygen atoms, two oxygen and two nitrogen atoms with a natural tendency to link together. The linkages repeats 45 times, stringing chains of about 1,700 atoms to form long, snaky polymers of nylon. Some types of nylon are made by synthesizing small molecules of butylene or benzene.

A variety of recipes may be used to remodel gaseous ethylene molecules into smooth acrilan fibers or durable Dacron. Or they may be given a crimping process to create fluffy Orlons. Another recipe synthesizes fibers for glass cloth from gaseous propylene. Molecules of gaseous methane are units of one carbon and four hydrogen atoms. At various stages of vigorous chemical processing, they lose one atom acid gain another, then gain another atom and finally polymerize to form long polymers for making acrylic fabrics.

The newly created polymers form in a tacky liquid. This is jetted into the air through fine holes. There the mixture dries, in thin, pliable fibers. Spinning machines twist bunches of them together. Other machines weave or knit the thread or yarns into fabrics, by the yard. In many ways, these marvelous man made textiles surpass nature's own silks, wools and cottons.