Ontario Grade 9 Science Practice Exam 2026 – Complete Study Resource

The purpose of a control group in an experiment is to provide a baseline for comparison. This group is not exposed to the experimental treatment or independent variable being tested, allowing researchers to observe the effects of the treatment by comparing it with the control group. By establishing a control, scientists can determine whether any observed changes in the experimental group are truly due to the treatment or if they could be attributed to other factors. This is essential for ensuring the validity and reliability of the experiment, as it helps to isolate the effects of the variable being tested.

In contrast, manipulating variables, increasing the number of variables, or introducing bias would complicate the experiment and make it difficult to draw accurate conclusions regarding the relationship between the independent and dependent variables. These practices would undermine the objective of scientific inquiry, which is to understand cause-and-effect relationships clearly and objectively. The control group, therefore, is critical for a well-structured experiment that seeks to uncover genuine insights.