Independent vs. Dependent • The independent variable is the manipulated or responding variable? The manipulated, because it is what you manipulate/change/control. • The dependent variable is the manipulated or responding variable? • The responded, because it depends on/responds to the independent/manipulated variable.
Example: What is the effect of the amount of air in a rocket balloon on the time that rocket balloon moves? What are we going to manipulate/change? • The amount of air in the balloon. What are we going to observe in response to the differing amounts of air? • The time that the rocket moves. So the independent/manipulated variable is? • The amount of air in the balloon. The dependent/responding variable is? • The time that the rocket moves.
Let’s Try It! Procedure. • Fill balloon with 2 pumps of air. • Let go of balloon in same direction and position. • Record the time the balloon is moving. • Repeat step 1-3 this time 4 pumps, then 6, then 8, then 10, then 12.
Read the Text • Get Textbook and then with a partner: • Read page independently page 639: Controlling Variables • Person A & Person B shares what a variable is (in your own words). • Person A shares what a manipulated variableis (in your own words). • Person B shares what a responding variable is (in your own words). • Both be ready to share with class.