Why are scientific experiments controlled?

Controlled experiments are designed to ensure that the results can be attributed to the variable being tested, rather than being influenced by other external factors. This is essential for establishing a clear cause-and-effect relationship and allows researchers to draw valid conclusions from the data collected. By controlling variables, scientists can isolate the effects of the independent variable on the dependent variable, which is the core principle of experimental design.

The emphasis on controlling external factors helps to minimize ambiguity and increases the reliability of the results. For example, if a scientist is testing the effect of a new fertilizer on plant growth, controlled conditions would ensure that other factors, such as soil type, water amounts, and light conditions, remain constant. This way, any differences in plant growth can be more confidently attributed to the fertilizer instead of other variables.

This approach distinguishes scientific methodology and enhances the reproducibility of results, enabling others to repeat the experiment under similar conditions to verify findings.