To setup a controlled science experiment, one must have a good understanding of the scientific method. The scientific method is a process, a set of guidelines, used to ensure the accuracy of the experiment, thus achieving "control." If one fails to follow the scientific method, a controlled experiment is impossible, and the results of the experiment are worthless.
Setup a Controlled Science Experiment Utilizing the Scientific Method
Begin by doing your research. Research is necessary to gather data that is used to formulate a hypothesis and to create the experiment.
Identify a problem. The problem is the question you are trying to answer. Without a problem, there is no reason for experimentation.
Formulate a hypothesis. The hypothesis is a statement, based on your research, that is intended to provide a solution to the problem. The hypothesis is what you are trying to prove or disprove.
Conduct your experiment to prove the hypothesis. A controlled science experiment is setup to test whether a variable has a direct causal relationship on another.
Identify your independent and dependent variables. The independent variable is commonly known as the cause, while the dependent variable is the effect. For example, in the statement A causes B, A is the independent variable and B is the dependent. A controlled scientific experiment can only measure one variable at a time. If more than one variable is manipulated, it is impossible to say for certain which caused the end result and the experiment is invalidated.
Do not alter your hypothesis midway through the experiment. The setup of a controlled scientific experiment must be constant. You can not make changes once you have begun, even if the results you are getting do not seem to support your original hypothesis. When you change your hypothesis, you change the entire experiment and you must begin again.
Do not be upset if your results are not what you expect. Some of the greatest scientific advances have come from experiments that disproved the original hypothesis.
Start over again with a new hypothesis or find new variables to manipulate. Scientific advancement is a painstakingly slow process and scientists often spend years and even an entire lifetime working on the same problem.
Failure to follow the scientific method precisely will invalidate all results of the experiment.