Scientist pay close attention to controls, dependent variables, and independent variables when they design experiments. Do the Chaper 3 Skill Activity on page 844 to learn how to identify controls and variables. How to identify control and variables. Procedure 1. Pour the same amount of water into two beakers. 2. Take the temperature of the water in each beaker to make sure the temperature are the same. 3. Add salt to one beaker and stir the water in both beakers until all the salt has dissolved. 4. Take the temperature of the water and of the salt solution. 5. How did dissolving salt in one beaker affect th water temperature? 6. What were the controls? Variables? The scientist take great care to make sure only one factor in the experiment, the independent variable. The independent variable is the "cause" factor. The factor that changes as a result of the independent variable is called the dependent variable. The dependent variable is what is measured