Science Experiments that involve variable and control?!?!?

I need a science experiment for highschool students that involves a variable and control. I need to write a method paper on it so I want something creative. I searched everywhere and I just can't find anything! Please help! Thanks.Science Experiments that involve variable and control?!?!?
Hi,





My daughter had to do one like this, and since it is Spring, she did plant seeds.





She planted bean plants in several cups. The variables were (1) amount of water, (2) amount of fertilizer, (3) amount of light. Then she measured the growth of the plants over time, carefully controlling different variables in each cup.





Just a thought. :-) Good luck!Science Experiments that involve variable and control?!?!?
These sites have or point to lots of science fair project ideas:





http://www.sciencebuddies.org/





http://www.all-science-fair-projects.com鈥?/a>





http://www.ipl.org/div/projectguide/





http://school.discoveryeducation.com/sci鈥?/a>





http://www.picadome.fcps.net/lab/sci_fai鈥?/a>





http://www.scienceproject.com/





http://www.energyquest.ca.gov/projects/i鈥?/a>





http://www.freesciencefairproject.com/





http://www.hometrainingtools.com/article鈥?/a>





http://www.usc.edu/CSSF/Resources/Gettin鈥?/a>