Variables

What are Variables?

• Factors that can change in an experiment.

Investigative QuestionInvestigative Question

Does increasing the drop height affect the bounce height of a superball?

What is a Manipulated Variable (also called Independent Variable)?• In an experiment, only one factor, or variable,

should be changed at a time.

• The one variable that is purposely changed in an experiment.

• A manipulated variable is the variable whose value we know beforewe know before we start an experiment.– Example: We know what the drop heights are

before we start.

What is a Responding Variable (also called the dependent variable)?

• A factor that may change in response to the manipulated variable.

• The variable whose value we do not we do not knowknow before we start an experiment.

• It is the data we collect in an experiment.– Example: We do not know the bounce

heights before we start.

What is an Experimental Group?

• In science, experiments often involve groups of things, rather than individual objects.

• It’s the group being studied

-Example: superballs dropped from different heights.

What is a Control Group?

• Purpose is to serve as a standard of comparison

• Used to see if we conducted a fair experiment

• In the control group, the conditions are the same as the experimental group except for the manipulated variable.– Example: The superballs dropped from the lowest

height.

What is a Controlled Variable?

• A factor that we keep constant, the same between the control and the experimental group

• There are usually many controlled variables in an experiment.

--Example: the type of floor, the way we drop the superball, the type of measuring device, how we determine the height