Some cool pages to check out! These may help you with your research :)
http://www.youtube.com/spacelab?feature=etp-gs-space(cool space experiments kids have done)
http://kids.nineplanets.org/title.htm explore the planets
http://htwins.net/scale2/ (What's the smallest/biggest thing in the universe? zoom in and out to see- Thanks Mr Young! This website is sooo cool!)
If you want to watch documentaries on your topic- ask your parents first- these links below have really amazing documentaries- but might be too difficult for some of you to understand.