How to Write a Hypothesis

Make sure your hypothesis can actually be tested.

If you're preparing to conduct any type of scientific experiment, you need to develop a thoughtful hypothesis to prove or disprove. Before you start writing, learn how to develop, refine and state a strong hypothesis -- which is essentially an educated guess.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Pen
• Paper

1. Come up with an idea for an experiment if you don't already have one or if one has not been assigned to you. Try to think of things that you expect to be able to test and definitively prove one way or another.

2. Determine the central question of your experiment. If you feel as though you need to conduct additional research to make an educated guess as to the answer of this question, do this research first. If not, write your prediction in your own words.

3. Verify that the prediction is provable and measurable. If it is, identify the independent and dependent variables. The independent variable is the element of your experiment that you will change. The dependent variable is the element of your experiment that you expect to change as a result of changing your independent variable.

4. Reword your hypothesis as an "if-then" statement using your independent and dependent variables, and make sure it states your prediction, not the question. For example, if your experiment involves testing to see if bleach kills grass and your prediction is that bleach will kill grass, you might state your hypothesis as: "If bleach is applied to grass, then the grass will die." In this case, the application of bleach is your independent variable and the life of the grass is your dependent variable.

Tips & Warnings

• After the experiment and the analysis of your results, be sure to prove that your hypothesis is either true or false.

References

• Science Buddies: Writing a Hypothesis for Your Science Fair Project