I am attempting to do an end of the year physics project on gears on bikes and bike ratios. For the presentation I want to explain how gear ratios and the like work and demonstrate a homemade gear. I also need to have and experiment to go along with it. My basic plan is to ride my bike up a short section of hill and measure the number of pedal rotations as well as possibly speed and calories for efficiency? I need some help coming up with variables to measure for my experiment and I am lost! Can you guys help?