Tony Dixon, age 13, of Champaign, I11., for his question:

HOW DOES A KALEIDOSCOPE WORK?

A kaleidoscope is a small tube in which you can see beautiful colors and designs. Most kaleidoscopes are about three inches in diameter and about 10 inches long. Both ends of the tube are closed, but one end has a small peephole through which you can look.

A kaleidoscope works on the principle of multiple reflection. Two glass plates inside serve as mirrors. They go down the entire length of the tube and slant toward each other. At the far end of the kaleidoscope are two more plates, one made of clear glass and the other of ground glass. The clear glass is closer to the eyehole.

Pieces of colored beads and glass are placed between the plates. The beads and glass are reflected in the mirrors. The ground glass throws the reflections in many directions and patterns are formed. When the viewer turns the kaleidoscope, the colored beads and glass shift positions and the reflected patterns change.

Designers often use this toy to find new patterns.

Sir David Brewster invented the kaleidoscope and patented it in 1817.