The Scientific Method
Student/Parent Guide for Science Fair Projects
1. Purpose – also called the problem or scientific question. Think of a question you have
about the world around you that you could find the answer to through an experiment.
Keep it simple! There is no reason the entire project needs to cost more than $20. Your
question should be something you couldn’t just look up, and it isn’t just building
something like a model volcano.
Example: What type of laundry detergent is best at getting out mustard stains from
white t-shirts?
2. Procedure – After you know what question you want to answer through your project,
it’s time to make a plan. List the steps you will follow when you conduct your
experiment, and be specific! Remember that you will need to conduct your experiment
three times. Some experiments have many steps, and some have less, but you should
probably have at least 8 steps in your procedure.
Example: List and number the steps you will follow when you use detergents to get out
mustard stains.
3. Materials – What will you need to conduct your experiment? Try and think of even
small things you need to stay organized. Be specific! List all of your materials before
you begin your experiment.
Example: French’s yellow mustard, water, thermometer, three brands of detergent (Tide,
Gain, Arm & Hammer), white cotton t-shirt fabrics, scissors for cutting shirts, trays for
washing shirts in water, measuring spoons, measuring cups, scrub brush, camera
4. Variables – When you are planning your experiment, you should also be thinking about
your variables. There are three different types of variables.
 Manipulated Variable – This is the one thing in your experiment that can change
from test to test. Everything else needs to stay the same (controlled). Example:
the brand of laundry detergent
 Controlled Variables – These are the parts of your experiment that need to stay
the same to make your tests fair. There are lots of controlled variables.
Examples: the temperature of water, brand and style of mustard, size of mustard
stain and amount of mustard, type of fabric, amount of detergent used, and
length of time washed
 Responding Variable – This is what you are measuring when you do your
experiment. It is the output of the experiment that will give you your data.
Example: observations made about the size and color of the stains after washing
5. Hypothesis – Here is where you make an educated guess about how your experiment
will turn out. What do you think will happen, and why? It doesn’t matter if you
hypothesis ends up being correct or not.
Example: I think that Tide will be the best at getting mustard stains out of white t-shirts
because it is advertised to have more cleaning chemicals than other brands.
6. Experiment – This is the fun part, and also the most important! You will follow your
procedure and conduct tests to answer your question. You will find out if your
hypothesis is correct or incorrect. Remember that you can only change the manipulated
variable, and the controlled variables need to stay the same for each test! Also, you will
need to conduct each test 3 times to make your results more valid. Take pictures of
your experiment if possible to use on your display board. (No faces shown for science
fair projects.)
Example: If you have three brands of detergent, you will need to test each brand three
times on getting out stains. You could test Tide three times, Gain three times, and Arm
& Hammer three times. This would mean that you actually conduct 9 tests total, three
for each detergent.
7. Analysis – Now it’s time to think about what your results mean. You will want to make
at least one graph, maybe a chart as well, showing the results of your experiments.
Record the outcome of each test and compare your results to your hypothesis.
Example: Take pictures of the different fabrics and label them after they have been
washed. It’s tough to make a mathematical graph of how stains have faded. Maybe
you could get some paint chip samples from a paint store or Home Depot and compare
them to the stains. Then you could create a scale to see how faded each stain was.
8. Conclusion – This is the last part of the scientific method. Describe what you found out
and what you learned in a paragraph. You will need to answer your scientific question
you had at the beginning. Here are some questions for you to answer:
 What happened in your experiment?
 Was your hypothesis correct of incorrect?
 Why do you think the experiment turned out the way it did?
 What did you learn from this project?
 Did this change the way you think about your topic?
 What could you recommend to someone else or teach them about this topic now
that your experiment is through?
Example: I found out that Gain was the best detergent for getting mustard stains out of white cotton tshirts. My hypothesis was incorrect. I think Gain worked the best on mustard stains because it had different
ingredients than the other two detergents (list the ingredients that were different). I predict that Gain would
also work well at getting out other types of stains beside mustard. My family will definitely be using Gain
detergent from now on!