posted by yasmin .
how do you change a theme (melody) in music to make variations?
It is hard to answer that question in words, since I have no training in music theory. If you have the means to listen to some examples, I suggest Variations on (Mozart's) La Ci Darem la Mano by both Beethoven and Chopin, and any of the dozens of variations on Paganini's Caprice #24 in A minor, especially the one by Rachmaninoff (Rhapsody on a Theme of Paganini).
Jazz musicians do variations on a theme all the time.
Thank you for using the Jiskha Homework Help Forum. Here are some things on Theme and Variation:
2. (pop): http://worshipguitarguy.wordpress.com/2006/08/09/theme-and-variation-a-page-from-classical-music/
3. (this explains well): http://themeandvariations.blogspot.com/2005/01/classical-music-forms.html
4. (Wikipedia): http://simple.wikipedia.org/wiki/Variations_(music)