Madison lives near the ocean. She’s formed a hypothesis that increased concentrations of salt in the air speeds the corrosion of certain metals. If Madison plans to test this hypothesis, she will have to deal with the following variables in her experiment: dependent variable: Air humidity, Air Temperature or Amount of metal corrosion

independent variable: Airborne salt concentrations, Volume of ocean water or ocean water temperature

one possible confounding variable: Air temperature, Airborne salt concentrations or color of nearby ocean waters