Experimental Definitions
What is a Variable? Something that changes in an experiment Examples: Amount of light or water Type of soil Speed of an object Grades Growth
The Independent Variable (Hint: Think CAUSE) The variable that you change on purpose Sometimes called the manipulated variable
Examples of Independent Variables Amount of light or water Type of soil Height of the ball drop
The Dependent Variable (Hint: Think EFFECT) The variable that changes/responds to the independent variable It is the variable that you measure in the experiment Sometimes called the responding variable
Examples of Dependent Variables Speed of an object Height/growth of a plant Distance traveled Grades
Constants Details in the experiment that do not change from trial to trial.
Examples of Constants Same type of seed (plant) Same size dropper Same amount of time
Control A standard for comparison in an experiment…sometimes called a placebo
Examples of Controls Plant that received no water or no light Patient who received a “sugar” pill (placebo)