An orchestra is a large ensemble combining string, wind, brass and percussion instruments. Sometimes, there are more unusual members of the orchestra such as electronic instruments, a wind machine or even car horns! There can be over 100 musicians in an orchestra, so there is usually a conductor who keeps the beat and directs the muscians using his hands and arms. In fact, the conductor is the only member of the orchestra who doesn’t make a sound! Orchestras tend to play Western classical music, including concert music, film music or music to accompany musicals and dance. The word orchestra can also be used for large ensembles playing jazz or music from other musical traditions.