What is the independent, dependent & control variable in a Water Rocket Experiment?

the experiment involves a rocket and a mixture of baking soda and vinegar to launch it now I think the variables are.... Independent:Rocket, Dependent: Height rocket goes to %26amp; control: the mixture but here is the prob... the mixture changes portions throughout the experiment!!! please help me!|||You don't control the mixture's proportions as the rocket launches, but you might compare the performance of rockets that use several different mixtures to a rocket propelled by a control mixture.