Read This! When designing an experiment, you need to consider three types of variables. The independent variable is changed by the experimenter by design. This variable is sometimes called the "manipulated variable." The dependent variable is whar changer as a result of the change in the independent variable. This variable is sometimes called the "responding variable." In some cases more than one dependent variable is considered. The third caregory involves controlled variables. These are variables that you think might change the outcome of the experiment, but since you are not studying them, you need to keep them constant in cach trial. 11. Identify the independent, dependent, and controlled variables for the experiments that produced the data shown in Model 2 and Model 3. Read This! A well-written research question states the independent and dependent variables for an experiment. For example, a srudent investigated the effect of the deicer, magnesium chloride, on vegetation on the sides of highways. Her research question was, "What is the effect of magnesium chloride solution concentration on the growth of rye grass?" 12. Write a research question, using the format suggested in the Read This box, for the experiments in Models 2 and 3. Alla-Seluer" and Vinegar - Boiling Points of Alcohols 13. A student wonders, "Will changing the volume of alcohol in a boiling point experiment change the boiling point of the liquid?" Identify the variables that should be considered in this experiment. Independent Dependent Controlled