Subject: How and why does a rubber band ball bounce?

I'm doing a project and I need information on it. My teacher wants us to get 
info. before we do the research paper. My project is: which can bounce higher, 
a rubber band ball filled with rubber bands in the middle or a rubber band ball 
with a tennis ball in the middle (with rubber bands around it). I know I need 
some thing on elastic potential energy, but not many sites can give that much 
info. on it.....so, if you can't give me an answer, can you tell me about 
elastic potential energy with a rubber band ball? Thanks!!!!! 

Re: How and why does a rubber band ball bounce?