Music Instrument: Guitars

--How is it played? What does the person have to do to produce sound?
Guitars  are played buy plucking the string on the instrument with finger or a pick.
The sound of an Acoustic guitar is from the vibrations of the strings and the hollow body of it.

--How do you change a note? (you might have to watch very carefully to see this)

depending on what guitar you are playing you have to use the pick (or your fingers).
Each string on the guitar has a different note. You adjust the notes to what song your are playing.

http://www.ehow.com/how_6192856_change-notes-bass-guitar.html

--How is it shaped?

The body of the instrument plays a major part in the sound that comes out of it. The  body of the guitar is hollow so when you pick a string, its reaction to the hollow part of the instrument gives you a sound.

--What does this make you think about how you can create and change sound?

This makes me think about what type of string I would used to create the vibration and how hollow does the body of the guitar have to be.