An orchestra will usually contain a few timpani drums of various sizes. Timpani are simple kettledrum instruments that are beaten to produce a note. They can also be tuned to achieve different pitches unlike other common drums.
Cymbals and gongs will be found in most orchestra ensembles. They are large metal discs that can be played in a number of ways. They can be hit with a beater, clashed together or played by slapping them together. Gongs are slightly different and are usually bigger and thicker than cymbals, requiring a soft beater to strike them.
One of the simpler percussion instruments, the triangle is a bent metal bar that is struck using a steel tangent to produce its sound.
The xylophone consists of a series of wooden bars, each of which is tuned to a different note on the musical scale. The bars are struck using a mallet, which can be made of either rubber, plastic or wood.
A tambourine is a wooden disk that holds several metal disks in its frame. These smaller disks then jingle and produce sound when the tambourine is shaken or the frame is struck. Some tambourines have a thin skin stretched across the frame that is struck like a drum.
The piano is essentially a large keyboard. As the pianist presses the keys, an internal hammer is made to strike a steel string to create a vibration. The energy then passes through a bridge to a sounding board, where it is released as sound.