Which Pain Reliever Dissolves Fastest?

I'm doing a science fair project and my topic is "Which Pain Reliever Dissolves Fastest." I'm using water and putting 1 different brand of pain reliever in each cup. I'll have about 5 cups total (Tylenol, Advil, Aleve, Motrin, Bayer, Excedrin). Is this the right way to set up this experiment? And should I mix the water with the pain reliever, or should I just let it sit there until it dissolves? And also, what would my control be?