The Scientific Method

A scientific method is a systematic way to answer scientific questions and present the results to the scientific community. Virtually all researchers follow scientific methods that look similar to the steps listed below:


After you've chosen the general topic of your science fair project, do some reading in that area to get some more specific ideas for a project and to learn as much as you can about the subject. Because this will help you understand and predict what will happen during your experiment, even young students should do at least some research. Try to find information from:

Notes and bibliography from all of this research should be recorded in the logbook/scientific notebook.

(For grades 6 to 12 only: This preliminary research, written up in the form of a short paper, becomes the bulk of the introduction of the project report. Parents: Some science fair sponsors [school teachers] require this short research paper of their students before they continue with their question and hypothesis, rather than putting it off and writing it with the rest of the project report after experimentation. This is recommended but is up to you.)


Ask a question that might be fun or interesting to find an answer to by conducting an experiment. For example, "Which fertilizer results in greatest bean production in bean plants?" Books or websites can give you ideas, but be careful! Some may suggest science fair questions that are really demonstrations.
How can you tell if your experiment is really a demonstration?
See sample science fair questions.


A hypothesis is an educated guess about what will happen as a result of your experiment. This is not a stab in the dark! It should be based on your research. For example, "I believe Brand Y will yield the most beans because it has the highest level of P."


A good question is just the beginning. The way you design your experiment to find the answer to your question is at least as important as the question itself. You must design a Controlled Experiment, which contains the following types of variables:

It is also necessary in a controlled experiment that the variables be measurable. Determine what you will measure and what instrument(s) to use.

Although measurements will be of time, distance, height, and so on, other valid results might be more observational (e.g., changes in color). In our example, the responding variable (plant height) would be measured in centimeters or inches, but differences in color would also be important to observe and document.

Set aside one test group as a control group, which will be subject to all conditions of the experiment except for the manipulated variable. In our example, the control group of plants would be grown under the same conditions as the test plants except that no fertilizer would be added.

When you have designed your experiment, write your materials and procedures in your logbook. Procedures should be written as a step-by-step list, not in paragraph form. Be sure to include measurements: how much, how often, how long. Then, as you conduct your experiment, be sure to follow your procedures carefully. It is important that you repeat each test several times so that you can be sure of your results. Enter all measurements into your logbook. Carefully observe what happens at all times, and write down everything! Remember to record dates and times accurately.


Organize all results in your logbook into charts or tables. Make preliminary graphs. If you don't find any trends, you may need to collect more data, or you may need to analyze it differently. Check your logbook if you notice any outlying points. You should do your best to explain wacky data. ("Bean plant #1 never bloomed. According to my logbook, that's the plant that the cat chewed on, so I probably should not include that point in my data analysis...") In other words, why do you think you got the results you did?


Was your hypothesis correct? (Discovering that your hypothesis was incorrect does not mean that the experiment was a failure!) What is likely to happen if someone else does this experiment? How do your results affect real life? How could you improve the experiment if you were to do it again?

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Questions? Contact the GPHSF Director. Last modified: 31 August 2004