Developing a winning science fair project requries an in-depth understanding of the scientific method. One of the steps in the scientific method that gives students the most trouble is the development of an experiment. This is because students often forget to develop a control experiment.

What Is an Experiment?

An experiment is used in a science fair project to test the relationship between two variables. The first variable is the dependent variable. This is the variable that will be measured for change. The second variable is the independent variable. This variable is the one that is manipulated. A good experiment will only deal with one independent and one dependent variable set. The goal of the experiment is to identify a cause and effect relationship between the two variables being examined.

For example, if the hypothesis for your electronics science fair projects is “the most efficient conductor of electricity is copper” then you will need to set up an experiment that tests various types of materials for conductivity efficiency. Your dependent variable in this case will be the conductivity efficiency measurement and the independent variable will be the material that you test for conductivity.

What Is a Control Experiment?

In order to determine if the results of the manipulation of the independent variable produces unique results a control experiment is required. The control experiment will be set up just like the test experiment, however, in the control the independent variable will not be manipulated.

If we return to the hypothesis used in the previous section then a control experiment can be set up. Since the student will want to compare all of the results to those that are based on copper wire conductivity, copper wire will be used in the control experiment.

Using the Control Experiment Data

Students will want to start by completing their control experiment first. The data that is collected in this experiment will need to be kept separate from the data collected in the test experiments. It will be used as a data baseline. All of the data collected from the other test experiments will be compared to that collected in the control experiment.

Statistical analysis tools and formulas will be used to determine two things. First it will be used to determine if there is a statistically significant difference between what the control experiment data shows and what the test experiment data shows. If there is a difference then correlations will be drawn. For example, in the case of the electronics science fair project the correlations may show that copper is not the most efficient conductor of electricity, or it may show that it is.

It is the student’s main goal to use the control experiment data and the test experiment data to prove or disprove their original hypothesis Disproving a hypothesis is the easiest of the two. All you have to do is show evidence that the hypothesis was false just once. However, students need to know that you can never really “prove” that a hypothesis is true. When your data supports your hypothesis you just add to the likelihood that it may be true.