GED Science TestPhysical ScienceEasy
A student is investigating the effect of temperature on the rate of a chemical reaction. They set up three identical experiments, but each at a different temperature: 10°C, 25°C, and 40°C. They measure how quickly a gas is produced in each experiment. In this investigation, what is the independent variable?
- AThe reaction vessel used
- BThe amount of gas produced
- CThe type of chemical reactants
- DThe temperature of the experiment
Show answer & explanationAnswer & explanation
Correct answer: D. The temperature of the experiment
The independent variable is the factor that is intentionally changed or manipulated by the experimenter. In this scenario, the student is actively changing the temperature to observe its effect.
Why the other options are wrong
- A. The reaction vessel should be kept constant in each experiment, making it a controlled variable.
- B. The amount of gas produced is the dependent variable, as it is measured in response to temperature changes.
- C. The type of chemical reactants should be kept constant to ensure a fair test, making it a controlled variable.
Independent Variable
The factor in an experiment that is intentionally changed or manipulated by the researcher.
- The 'cause' in a cause-and-effect relationship
- What the experimenter controls directly
- Its effect on the dependent variable is measured
Memory trick: I Change D Measure C Control.