Kevin Finley, age 12, of Camden, N.J., for his question:

HOW ARE SILICONES USED?

Silicone is the name given to a family of man made materials. Silicones, which come in solid, liquid and gaseous forms, are now in use in thousands of industries. Scientists are discovering new applications almost daily.

As release agents, silicones keep bread from sticking to pans in commercial bakeries. Clean and smokeless, they work better than the grease that was once used.

Silicones also keep tires and other rubber and plastic parts from sticking in the molds. Silicone fluids are also used as polishing agents for automobiles, furniture and eye glasses. They keep instrument pointers on automobile dashboards from wobbling.

Fabric and leather treated with silicone will not absorb water or water based products such as ink and tomato juice. Repeated washing or dry cleaning will not remove the effect of silicone. Yet silicone will not stiffen the fabric.

Silicone oils and greases serve as permanent lubricants for clocks and ball bearings. Also, silicone water repellents keep brick and concrete walls dry in the rain.

Silicones are used in some hand lotions. They are also used in some paints. Paints made with silicone resins do not blister and peel off at temperatures of 500 to 1,000 degrees Fahrenheit. Silicone paints are often used on ships.

As electrical insulating materials, silicones make hard working motors, generators and transformers last 10 to 100 times as long as they ever did before. They make it possible for a 10 horsepower motor to do as much work as a 15 horsepower motor.

Silicone rubber does not melt at oven temperataures or become hard and brittle at temperatures far below zero. It is used to insulate communications cables on naval vessels and motor coils in diesel electric locomotive as well as to seal oven doors.

Silicones can be made in the form of fluids, resins and varnishes or gums.

Silicones are a cross between organic materials such as oils, rubber and plastics and inorganic materials such as sand, glass and quartz. Their key material is silicon. Silicon is the most common element in the earth's crust except for oxygen.

Silicones are several times as heat stable and weather resistant as organic materials. Like sand, glass and quartz, silicones have a molecular skeleton of alternating silicon and oxygen atoms. And the links in this chain are strong. The linkage, or bond strength, between silicon and oxygen is about one and a half times as great as the carbon to carbon bond that holds organic molecules together.

In making silicone products, "flesh" is put on the silicon oxygen skeleton with certain organic groups. These organic groups give the silicons such useful properties as water repellency, lubricating properties, flexibility and ease of handling.

Silicone greases and compounds are made by adding fillers. Silicone rubber is made by adding fillers and volcanizing agents.