4 Families of An Orchestra.

String

Woodwind

Brass

Percussion 

String: Violin, viola, double bass, harp

Generally the string family is categorized as the string because they are played in the particular way of the stick stroking the strings or strumming with the fingers. The instrument in the string family are made out of wood and for a certain period of time catgut was the most effective way to construct a violin, harp, cello etc. Musically instruments these days are made out of steel or polymer.

Woodwind: piccolo, flute, oboe, English horn, clarinet, E-flat clarinet, bass clarinet, bassoon and contrabassoon. 

The woodwind instruments are usually made out of wood or hallowed out reed and in rare cases it is made out of a metal. You play them by blowing air through the mouthpiece (that's the "wind" in "woodwind") and opening or closing the holes with your fingers to change the pitch. Metal caps called keys cover the holes of most woodwind instruments.

Brass: trumpet, French horn, trombone, and the tuba.

Brass instruments are made out of mental. Like the woodwind family, brass players use their breath to produce sound, but instead of blowing into a reed, you vibrate your own lips by buzzing them against a metal cup-shaped mouthpiece. The mouthpiece helps to amplify the buzzing of the lips, which creates the sound. Most brass instruments have valves attached to their long pipes; the valves look like buttons. When you press down on the valves, they open and close different parts of the pipe. You change the pitch and sound by pressing different valves and buzzing your lips harder or softer.

Percussion: timpani, xylophone, cymbals, triangle, snare drum, bass drum,tambourine, maracas, gongs, chimes, celesta and piano.

The percussion family is the largest in the orchestra. Percussion instruments include any instrument that makes a sound when it is hit, shaken, or scraped. It's not easy to be a percussionist because it takes a lot of practice to hit an instrument with the right amount of strength, in the right place and at the right time. 

                                            The Harp

                                         What is a Harp?

A Harp is a musical instrument consisting of a frame supporting a graduated series of parallel strings, played by plucking with the fingers. The modern orchestral harp has an upright frame, with pedals which enable the strings to be re-tuned to different keys.

Structure and System

Harps are essentially triangular in shape, and are made generally made         primarily of wood. Harp strings are generally of gut or metal. The top end of each string is secured on the crossbar or neck of the instrument, where generally each will have a tuning peg or similar device to adjust the pitch of that string.
                      The History

The earliest evidence of the harp is found in Ancient Egypt circa 2500 BC. They were shaped liked bows or angular and had very few strings (because they lacked a column they could not support much string tension).The frame harp, or a harp that included a straight fore pillar (or column in the modern sense), first appeared in Medieval Western Europe in the 8th to 10th centuries AD. Although there are very few remaining in existence, art from that time indicates they utilized about ten or eleven strings. The first harp to feature a hollowed sound box that amplified the instrument's sound dates back to Ireland in the 14th century. It also included a curved fore pillar, a stronger neck and 30 to 36 brass strings.

Types of Harps (not all are included):

The Lyre

The Crwth

Ancient Egyptian Harps

Medieval Harps

Modern Wire Harps

Multi-Course Harps - Double, Triple and Cross-Strung

Modern Lever/Celtic/Folk Harps, & Modern Gothic Harps

Cross-strung harps

Paraguayan & Latin-American Harps

The Aeolian or Wind Harp

The Electric Harp

The Earth Harp

The Bell Harp

The Psaltery-Harp

The Harp Guitar

Small Facts:

The harp is one of the oldest instruments in the world. Early pictures of ancient Sumerians playing harps were found by archeologists and date back to later than 3,000 BC! All harps have 3 different colors of strings: The C strings are red, F strings are black. (these are sometimes blue) The remaining are white or transparent. Celtic harps usually have 22-38 strings, where 3/4 size-concert grand size harps usually have 40-47 strings. Concert grand harps have 7 foot pedals at the base of the harp to change chromatics. Celtic or "lever" harps have little levers at the top of usually each string for chromatic changes. Some pedal harps are gilded with gold or encrusted with diamonds and jewels- these harps can cost upwards to $60,000! Lap harps can weigh as little as 4.5 pounds, where a pedal harp can weigh over 120! How You Position The Harp: The harp is usually positioned in between the thighs and strummed with the fingers in order to recieve a sound.