Strings

Woodwind

Percussion

The brass section usually sits on raised platforms above the string and woodwind sections.  Brass instruments use a mouthpiece and the vibration of the players lips against this makes a sound.  Most brass instruments use keys to create a range of notes but the trombone uses a slide. 

Although brass instruments do have solos, they often provide weight and volume to the music as well as a range of orchestral 'colours'.  The standard brass instruments and their families are:

Main Instrument	High	Low
Trumpet	Cornet
Trombone	Alto Trombone	Bass Trombone
French Horn
Tuba

However, there are other brass instruments that composers use.  Brass players often have to be versatile and be able to play a range of instruments, from common ones such as the Euphonium and Baritone to the Wagner Tuba, which is used to great effect in Stravinsky's The Rite of Spring.

Did you know?

Some old brass instruments did not use any keys and the different notes were made using the player's lips alone.  These 'natural' instruments were only able to produce notes from the harmonic series and therefore could not play the whole range of notes available to the more modern keyed instruments.  You can see these instruments used in period instrument orchestras.