Bill Ryan, age 12, of Greenville Miss., for his question:

WHEN WERE TRUMPETS FIRST USED?

' Trumpets are wind instruments sounded by the vibration of the player's lips against a mouthpiece. Trumpets made of large conch shells are used today as ritual instruments in many nonliterate cultures. And silver and bronze trumpets with long, straight tubes, conical bores and flared bells survive from ancient Egypt.

Other ancient trumpets were used by the Hebrews, the Romans and the Greeks.

In medieval Europe the long, straight trumpet called buisine was replaced by a shorter version about 1300. By 1400 it became folded into an S shape and about 1500 it was coiled into an elongated loop. In this form, made of brass or silver, it was the standard ceremonial and orchestral trumpet until about 1800.

In the early 1800s instrument builders sought to construct a trumpet that could play a full chromatic scale throughout its range. About 1820 valves were added. Opening a valve connected an extra increment of tubing, thus lowering the basic pitch of the instrument and providing a different harmonic series.

The modern trumpet has three valves and a bore that is partly cylindrical and partly conical.