1. Overview of the Scientific Method
The scientific method is a process for experimentation that is used to explore observations and answer questions.
Scientists use the scientific method to search for cause and effect relationships in nature. In other words, they
design an experiment so that changes to one item cause something else to vary in a predictable way.
Just as it does for a professional scientist, the scientific method will help you to focus your science fair project
question, construct a hypothesis, design, execute, and evaluate your experiment.
Ask a Question: The scientific method starts when you ask a question about something that you observe: How,
What, When, Who, Which, Why, or Where?
And, in order for the scientific method to answer the question it must be about something that you can measure,
preferably with a number.
Do Background Research: Rather than starting from scratch in putting together a plan for answering your question,
you want to be a savvy scientist using library and Internet research to help you find the best way to do things and
insure that you don't repeat mistakes from the past.
Construct a Hypothesis: A hypothesis is an educated guess about how things work:
"If _____[I do this] _____, then _____[this]_____ will happen."
You must state your hypothesis in a way that you can easily measure, and of course, your hypothesis should be
constructed in a way to help you answer your original question.
Test Your Hypothesis by Doing an Experiment: Your experiment tests whether your hypothesis is true or false. It is
important for your experiment to be a fair test. You conduct a fair test by making sure that you change only one factor
at a time while keeping all other conditions the same.
You should also repeat your experiments several times to make sure that the first results weren't just an accident.
Analyze Your Data and Draw a Conclusion: Once your experiment is complete, you collect your measurements
and analyze them to see if your hypothesis is true or false.
Scientists often find that their hypothesis was false, and in such cases they will construct a new hypothesis starting
the entire process of the scientific method over again. Even if they find that their hypothesis was true, they may want
to test it again in a new way.
Communicate Your Results: To complete your science fair project you will communicate your results to others in a
final report and/or a display board. Professional scientists do almost exactly the same thing by publishing their final
report in a scientific journal or by presenting their results on a poster at a scientific meeting.
OBSERVATION
This step could also be called "research." It is the first stage in understanding the problem you have chosen. After you
decide on your area of science and the specific question you want to ask, you will need to research everything that
you can find about the problem. You can collect information on your science fair topic from your own experiences,
books, the internet, or even smaller "unofficial" experiments. This initial research should play a big part in the science
fair idea that you finally choose.
Let's take the example of the tomatoes in the garden. You like to garden, and notice that some tomatoes are bigger
than others and wonder why. Because of this personal experience and an interest in the problem, you decide to learn
more about what makes plants grow.
For this stage of the Scientific Method, it's important to use as many sources as you can find. The more information
you have on your science fair project topic, the better the design of your experiment is going to be, and the better
your science fair project is going to be overall. Also try to get information from your teachers or librarians, or
professionals who know something about your science fair topic. They can help to guide you to a solid experimental
setup.

2. HYPOTHESIS
The next stage of the Scientific Method is known as the "hypothesis." This word basically means "a possible solution
to a problem, based on knowledge and research." The hypothesis is a simple statement that defines what you think
the outcome of your experiment will be.
All of the first stage of the Scientific Method -- the observation, or research stage -- is designed to help you express a
problem in a single question ("Does the amount of sunlight in a garden affect tomato size?") and propose an answer
to the question based on what you know. The experiment that you will design is done to test the hypothesis.
Using the example of the tomato experiment, here is an example of a hypothesis:
TOPIC: "Does the amount of sunlight a tomato plant receives affect the size of the tomatoes?"
HYPOTHESIS: "I believe that the more sunlight a tomato plant receives, the larger the tomatoes will grow.
This hypothesis is based on:
(1) Tomato plants need sunshine to make food through photosynthesis, and logically, more sun means more food,
and;
(2) Through informal, exploratory observations of plants in a garden, those with more sunlight appear to grow bigger.
PREDICTION
The hypothesis is your general statement of how you think the scientific phenomenon in question works. Your
prediction lets you get specific -- how will you demonstrate that your hypothesis is true? The experiment that you will
design is done to test the prediction.
An important thing to remember during this stage of the scientific method is that once you develop a hypothesis and a
prediction, you shouldn't change it, even if the results of your experiment show that you were wrong.
An incorrect prediction does NOT mean that you "failed." It just means that the experiment brought some new facts to
light that maybe you hadn't thought about before. The judges at your science fair will not take points off simply
because your results don't match up with your hypothesis.
Continuing our tomato plant example, a good prediction would be: Increasing the amount of sunlight tomato plants in
my experiment receive will cause an increase in their size compared to identical plants that received the same care
but less light.
EXPERIMENT
This is the part of the scientific method that tests your hypothesis. An experiment is a tool that you design to find out if
your ideas about your topic are right or wrong.
It is absolutely necessary to design a science fair experiment that will accurately test your hypothesis. The
experiment is the most important part of the scientific method. It's the logical process that lets scientists learn about
the world. On the next page, we'll discuss the ways that you can go about designing a science fair experiment idea.
CONCLUSION
The final step in the scientific method is the conclusion. This is a summary of the experiment's results, and how those
results match up to your hypothesis.
You have two options for your conclusions: based on your results, either (1) you CAN REJECT the hypothesis, or (2)
you CAN NOT REJECT the hypothesis.
This is an important point. You cannot PROVE the hypothesis with a single experiment, because there is a chance
that you made an error somewhere along the way. What you can say is that your results SUPPORT the original
hypothesis.
If your original hypothesis didn't match up with the final results of your experiment, don't change the hypothesis.
Instead, try to explain what might have been wrong with your original hypothesis. What information did you not have
originally that caused you to be wrong in your prediction? What are the reasons that the hypothesis and experimental
results didn't match up?
Remember, a science fair experiment isn't a failure if it proves your hypothesis wrong or if your prediction isn't
accurate. No one will take points off for that. A science fair experiment is only a failure if its design is flawed. A flawed
experiment is one that (1) doesn't keep its variables under control, and (2) doesn't sufficiently answer the question

3. that you asked of it.