Thank you for using the Jiskha Homework Help Forum. That is difficult to choose for YOU, since we don't know your likes and dislikes. Try the following for ideas;
2. (part II of #1): http://www.free-science-fair-projects.com/high-school-free-science-fair-projects.aspx
4. (part II of #3): http://classroom.all-science-fair-projects.com/forum/forumdisplay.php?f=43
If you don't find anything you like, there are many more under GOOGLE: 11th grade Science Fair Projects.