Stephen Mackovick, age 12, of Chattanooga, Tenn., for his question:

WHO INVENTED THE HARP?

The harp is the oldest stringed instrument in the world. Archeologists have found one harp that was made by the Sumerians more than 4,500 years ago.

The Bible says the harp was invented by Jubal. There too we read that it was the musical accompaniment for the psalms of the ancient Jews, and that it was played by King David.

A double harp, called David's harp, is played with the fingers and thumbs of both hands. It is a triangular shaped instrument with a sounding board and catgut strings.

The strings of the double harp are usually tuned to the principal key of the music. Pressure of the thumb or a turn of the tuning pins allows the player to make a change in the pitch of the note that each string produces.

The pedal harp was invented by Celestin Hochbrucker in about 1720. It has seven pedals that can make each note of the scale in each octave a half note higher.

A double action pedal harp was invented in 1810 by Sebastian Erard. This version of the harp allows two changes in the length of strings and thus two tone changes.

The most common harp today is a large instrument that rests on the floor and is held between the knees of the seated player. It is used often in symphony orchestras and also as a solo instrument in concerts.

The autoharp is a more modern development. A musician holds it in his lap to play it. The harp was the favorite instrument of the old Irish poets, and it has become one of the emblems of Ireland, as much a part of the Irish lore as the shamrock.

Related to the harp is the harpsichord, a musical instrument that actually resembles a piano. It can be played as a solo instrument, in a chamber music ensemble or with an orchestra.

Lighter and smaller than a piano, the instrument first appeared in the 1300s, but no one knows who invented it. By the 1700s, some harpsichords had two keyboards called manuals. Johann Sebastian Bach and other composers of the day wrote harpsichord music.

Strings on a harpsichord are stretched over two strips of wood called the bridge and the nut. The bridge is glued to a thin sheet of wood called the soundboard, and the nut is glued to a block of wood that runs parallel to the keyboard and holds the tuning pins.

Like a regular harp, the strings of a harpsichord are plucked. They are not struck like those of a piano.