Independent, Dependent & Controlled Variables Lesson

Students define independent, dependent, and controlled variables in a scientific experiment.

Students identify a flaw in an experimental design where more than one variable was changed at once.

Students design controlled variables for novel experimental scenarios, such as basketball shooting or building a soap box derby car.

Use as an introduction to a science fair unit, as the cover page itself suggests.

Have students attempt the fill-in-the-blanks and application table individually or in pairs before revealing the answer key, since the cover page notes the lesson is designed for brainstorming.

Discuss the tomato-plant scenario's flaw as a class before moving to the three application scenarios, since identifying that mistake sets up the rest of the worksheet's vocabulary.

Variable identification — students identify the independent, dependent, and controlled variables in a flawed tomato-plant watering experiment.

Experimental design critique — students explain why changing two variables (location and watering liquid) at once invalidates the plant experiment's conclusion.

Applied variable design — students propose an independent variable, a dependent variable, and at least three controlled variables for basketball shooting, studying for a test, and building a soap box derby car.