This worksheet describes the difference between an independent (manipulated) and dependent (responding) variables. The manipulated variable is the one that is changed in an experiment. The responding variable is what you measure. For example, if you give fertilizer to a plant and measure its growth, the manipulated variable is the fertilizer. The responding variable is growth.

In this assignment, students practice by identifying variables in short sentences. The sentence are very basic descriptions of a potential scientific experiment. For example:

 “You spray mosquito repellant on one arm and count how many mosquito bites you have.”

In this case, the mosquito repellent is the manipulated variable, and the number of mosquito bits is the responding variable.

Instead of answering questions, students underline the manipulated variable and highlight the responding variable in each sentence.

If you want a more robust exercise that also looks at data, controls, and conclusion, check out this worksheet. It could also be used as an assessment.