How to Write a Testable Hypothesis

Which freezes faster, hot or cold water? is a testable observation.
••• Photos.com/Photos.com/Getty Images

A testable hypothesis is one that can be used as the basis for an experiment. It predicts the correlation between two variables and can be tested by varying one of the variables. If the variables cannot be measured, the hypothesis cannot be proved or disproved. If one of the variables cannot be varied, it is impossible to conduct an experiment. If more than one variable is changed, the results are inconclusive. To write a testable hypothesis, it is important to consider how it will be tested and what makes for a valid experiment.

    Make an observation about the correlation between two things. This can be in the form of a question, such as, "Which freezes faster, hot water or cold water?" or in the form of a theory, such as, "Cold water probably freezes faster than hot water."

    Evaluate the observation and list the variables. For the observation about water, there are two: the temperature of the water and the time it takes the water to freeze.

    Evaluate the variables to determine whether they can be varied or measured. The water temperature and the time it takes to freeze are measurable, and one of the variables, the temperature of the water, can be varied. Also consider how to keep all other variables, such as the size of the ice cube trays and their placement in the freezer, constant so that only the temperature of the water changes.

    Consider how you would test the variables to explore your observation. For example, you could boil water, pour it into ice cube trays and put the trays in the freezer, then note the time it goes into the freezer and how long it takes to freeze. You could then take cold water and do the same thing. In each case, you would measure the temperature of the water before putting it into the freezer. The process could be repeated several times to create enough data to determine whether there is a correlation between water temperature and how long it takes to freeze. If you cannot determine a way to test or observe the variables, you have no basis for a good hypothesis.

    Write a statement that includes the variables and predicts an outcome that can be tested. For example, "The colder the water used in ice cube trays, the faster it will freeze." This is a testable hypothesis.

Related Articles

Water Evaporation Science Fair Projects
Difference Between Manipulative & Responding Variable
Science Projects on What Liquid Freezes Faster
What Is a Testable Prediction?
Definitions of Control, Constant, Independent and Dependent...
What Are Dependent, Independent & Controlled Variables?
Why Does Adding Salt to Water Make it Colder?
Why Should You Only Test for One Variable at a Time...
Experiments on Evaporation & Surface Area
Science Projects: How Hot & Cold Water Changes a Balloon
What Is the Incubation Period for Duck Eggs?
Why Should We Make Multiple Trials of an Experiment?
How to Do a Science Project Step-by-Step
What Is the Meaning of Variables in Research?
What Is a Standardized Variable in Biology?
Difference Between Data & Conclusion of a Study
What Happens When You Put Dry Ice in Water?
How to Float an Egg in Water
How to Start a Good Hypothesis
Ideas for a Science Fair Project Using Kool-Aid