Below are a few websites to help you search for a Science Fair Topic
http://www.education.com/science-fair/high-school/
http://www.sciencebuddies.org/science-fair-projects/science_project_ideas.php
http://www.projects.juliantrubin.com/science_fair_project/awardwinning/winning_11th_grade.html
http://chemistry.about.com/od/sciencefairprojects/a/sciprohigh.htm
http://www.education.com/science-fair/high-school/
http://www.sciencebuddies.org/science-fair-projects/science_project_ideas.php
http://www.projects.juliantrubin.com/science_fair_project/awardwinning/winning_11th_grade.html
http://chemistry.about.com/od/sciencefairprojects/a/sciprohigh.htm