ATI TEAS (Test of Essential Academic Skills) Version 7ScienceHard
A student is designing an experiment to investigate the effect of different light intensities on the rate of photosynthesis in a specific plant species. They measure the amount of oxygen produced by the plant under varying light conditions while keeping carbon dioxide concentration, temperature, and water availability constant. What is the dependent variable in this experiment?
- ACarbon dioxide concentration
- BPlant species
- CAmount of oxygen produced
- DLight intensity
Show answer & explanationAnswer & explanation
Correct answer: C. Amount of oxygen produced
The dependent variable is the factor that is measured or observed as a result of changes made to the independent variable. In this experiment, the student is varying light intensity (independent variable) and measuring the amount of oxygen produced, making oxygen production the dependent variable.
Why the other options are wrong
- A. Carbon dioxide concentration is a controlled variable, kept constant to ensure a fair test.
- B. Plant species is a controlled variable, kept constant to ensure the results are specific to that species.
- D. Light intensity is the independent variable, as it is being intentionally changed by the student.
Dependent Variable
The variable in an experiment that is measured or observed, and whose value is expected to change in response to manipulations of the independent variable.
- It 'depends' on the independent variable.
- It is the effect in a cause-and-effect relationship.
- Often plotted on the y-axis of a graph.
Memory trick: Independent is Input, Dependent is Data, Controlled is Constant.