Lee has given you PERFECT examples of "a symphony" and a source of information on them. I want to suggest some ideas for topics I think the essay should answer. I'm writing this WITHOUT having looked at WIkipedia and it may be interesting to see how they organize the subject compared to what I do. It should mention that a symphony is a piece of classical, "high-art," Western music played by a large orchestra of about a hundred musicians. It should mention the instruments in a symphony orchestra. It is different from a jazz combo or a marching band. It does not include accordions, electric guitars, banjoes, or mandolins for example, It should say that it is large-scale musical form, lasting typically 30-60 minutes, and divided into four separate sections called "movements." it should mention that it is played without any improvisation. In principle, every orchestra that plays Beethoven's Fifth Symphony plays the same notes from the same written score. The conductor is responsible for deciding on the musical interpretation. It should mention something about history and name a few famous composers and their best-known works. Depending on your audience--what your teacher expects--you might try listening to Beethoven's Fifth Symphony from beginning to end and say something about your personal reactions to it.

Hi Caterpillar, Here is a very famous symphony = Beethoven's 5th Symphony https://www.youtube.com/watch?v=6z4KK7RWjmk&list=RDt3217H8JppI&index=4 Here is all the information you need on Symphony http://en.wikipedia.org/wiki/Symphony Good luck!