What Is a Controlled Experiment?
A controlled experiment is a scientific test designed to determine the effect of a single variable by changing it while keeping all other conditions constant. This method allows researchers to isolate the cause of an outcome and establish a clear cause-and-effect relationship between variables.
Section 2: Key Components of a Controlled Experiment
A controlled experiment has several critical components. The independent variable is the single factor that the scientist intentionally changes. The dependent variable is the factor that is measured to see the effect of the change. A control group, which does not receive the experimental treatment, serves as a baseline for comparison. Finally, constants (or controlled variables) are all other conditions that are purposefully kept the same for all groups in the experiment.
Section 3: A Practical Example of a Controlled Experiment
Imagine you want to test if a new fertilizer helps plants grow taller. You would take two identical plants. Plant A gets the fertilizer (the experimental group), while Plant B does not (the control group). Here, the independent variable is the fertilizer, and the dependent variable is the height of the plants. The constants would be the amount of sunlight, water, soil type, and temperature, which must be the same for both plants.
Section 4: Why Are Controlled Experiments Important?
The primary importance of a controlled experiment is its ability to provide reliable and valid evidence. By manipulating only one variable and keeping everything else the same, scientists can minimize the influence of other factors on the results. This makes it possible to conclude with a higher degree of confidence that the changes observed in the dependent variable are a direct result of the changes made to the independent variable.