GED Science TestLife ScienceEasy
A student is designing an experiment to investigate the effect of different types of soil on plant growth. They set up three identical pots, each with a different soil type (sandy, clay, and loam), and plant the same species of seed in each. All pots receive the same amount of water and sunlight. Which of the following is the independent variable in this experiment?
- APlant growth
- BType of soil
- CAmount of water
- DSpecies of seed
Show answer & explanationAnswer & explanation
Correct answer: B. Type of soil
The independent variable is the factor that is intentionally changed or manipulated by the experimenter. In this experiment, the student is varying the type of soil to observe its effect.
Why the other options are wrong
- A. Plant growth is what is being measured or observed in response to the soil type, making it the dependent variable.
- C. The amount of water is kept constant, making it a controlled variable.
- D. The species of seed is kept constant to ensure a fair test, making it a controlled variable.
Independent Variable
The variable in an experiment that is intentionally changed or manipulated by the researcher to determine its effect on the dependent variable.
- The 'cause' in a cause-and-effect relationship.
- Only one independent variable should be tested at a time.
- Plotted on the x-axis of a graph.
Memory trick: Independent Is What I Change, Dependent Is What I See.