Percussion instruments like drums are among the oldest instruments in the world. Drums are made of animal skins stretched over wood or metal frames to produce a resonant tone. Used to provide rhythm for the orchestra, some drums can be tuned to a specific, recognizable pitch while others produce a sound but no specific tone. Timpani drums are large kettle drums with rounded bottoms that can be tuned to particular pitches. Untuned rhythm instruments include snare drums, bass drums, tenor drums and side drums. Drums are played by being struck with objects such as drumsticks, mallets, beaters, hands, brushes or sounders.
Some orchestra music uses pianos or other tuned percussion instruments to play the melody. These instruments have blocks, bars or tubes arranged like keyboard keys. Xylophones, marimbas, tubular bells, the celesta and the glockenspiel have a recognizable pitch so they can be used as melody instruments in an orchestra. The xylophone is made of wood with slabs laid side by side in two rows that produce a ringing melody when struck. A marimba is larger than a xylophone and produces a deeper, mellow sound. A glockenspiel resembles a small xylophone, is made of metal and is struck with metal mallets to produce a chiming sound. A celesta is made of metal, resembles a small piano and requires familiarity with a keyboard in order to play it. Tubular bells, or chimes, are long, thin-walled metal tubes plugged at one end and cut to certain lengths to produce particular pitches.
Instruments used to produce unique sounds, create special effects or add to the mood of orchestra music selections may be tuned or untuned. Tambourines, cowbells, claves and maracas are untuned instruments that are shaken to produce a sound. Wood blocks and castanets are scraped or struck together to produce untuned sounds. Cymbals and gongs are are made of sheets of metal that are struck to provide resonating sound. Cymbals can also be clashed together. Triangles are tuned instruments that are struck with another object to produce a pitch.