The purpose of using controls in scientific experiments is to ensure the reliability and validity of the results by providing a standard for comparison. A control is a group that does not receive the experimental treatment, allowing researchers to isolate the effects of the independent variable. This helps in identifying any changes that can be attributed to the treatment rather than other factors. By minimizing variations, controls enhance the scientific rigor of the study. This practice is fundamental in experimental design, contributing to the reproducibility and credibility of scientific findings.