In an experiment measuring bacterial growth at different temperatures, what is the independent variable?

• A. Bacterial growth rate
• B. The type of bacteria
• C. Temperature
• D. The time measured

Answer: (C)

In this experiment, the independent variable is temperature because it is the factor that is intentionally manipulated to observe how it affects bacterial growth. The independent variable is the one that is changed or controlled in a scientific experiment to test its effects on the dependent variable, which in this case is the bacterial growth rate. By varying the temperature, researchers can determine how different thermal conditions influence the growth patterns of the bacteria being studied.

The other factors mentioned are important to the experiment's context but do not represent the independent variable. Bacterial growth rate is the dependent variable that is measured to assess the impact of the temperature changes. The type of bacteria could also influence the experiment, but it remains constant as part of the experimental design in this case. Additionally, time measured serves as a controlled factor in the experiment but does not change the temperature itself.