What Is a Testable Prediction?

In science, it's important that a hypothesis make testable predictions.
••• Ryan McVay/Photodisc/Getty Images

In science, an educated guess about the cause of a natural phenomenon is called a hypothesis. It's essential that hypotheses be testable and falsifiable, meaning they can be tested and different results will ensue depending on whether the hypothesis is true or false. In other words, a hypothesis should make predictions that will hold true if the hypothesis itself is true. A testable prediction can be verified through experiment.


If you have an explanation for a natural phenomenon -- in other words, a hypothesis -- you can use it to make predictions. Suppose you notice, for example, that more salt dissolves in hot water than in cold water. You could hypothesize that perhaps all compounds are more soluble in hot solvents than in cold solvents. Based on this hypothesis, you would predict that as the temperature of the solvent increases, so, too, does the amount of solute you can dissolve.

Testing Predictions

All predictions should be testable, meaning it should be possible to design an experiment that would verify or invalidate the prediction. With the solvent, for example, you could test your prediction by dissolving different compounds in water at different temperatures and measuring the solubility. You would soon find that some substances actually become less soluble with increasing temperature. Since the prediction made by your hypothesis is false, you would realize your hypothesis is flawed and try to find a new one that could account for the facts.

Untestable Predictions

Untestable predictions and hypotheses lie outside the realm of science. Suppose someone told you, for example, that lightning storms are caused by angry ghosts. If this is true, you would predict that when ghosts are angry, there will be more lightning storms. It's not a valid scientific hypothesis, however, because neither the proposed explanation nor its predictions are testable. There is no possible experiment you can design to determine whether ghosts are angry and whether their wrath is correlated with the incidence of thunderstorms, so the hypothesis and its predictions are completely untestable.


There's a common misconception that scientists "prove" a hypothesis is true. In reality, no number of experiments can ever prove a hypothesis is true beyond all doubt; they can only show it's consistent with the evidence. As evidence accumulates and competing explanations are disproven, of course, it becomes more and more reasonable to believe the hypothesis is the best explanation. At this point scientists will refer to it as a theory (for example, the theory of relativity). It takes only a single experiment to disprove a theory, but a thousand experiments cannot prove it true. Nonetheless, if a theory and its predictions have been repeatedly verified by experiment, it will be generally accepted, unless there is sufficient evidence to show it should be discarded in favor of a new theory.

Related Articles

What Are the 8 Steps in Scientific Research?
Difference Between Proposition & Hypothesis
How to Calculate Solubilities
How to Do a Science Project Step-by-Step
Science Projects on What Freezes Faster: Water or Sugar...
How to Write a Testable Hypothesis
Five Characteristics of the Scientific Method
What Does Soluble Mean in Science?
10 Characteristics of a Science Experiment
Does the Density Affect the Rate That a Liquid Freezes...
Why Must a Burette & Pipette Be Rinsed With the Appropriate...
The Difference Between Research Questions & Hypothesis
Why Should We Make Multiple Trials of an Experiment?
What Is a Constant in the Scientific Method?
The Disadvantages of Simple Distillation
Science Project: The Effects of Temperature on Liquids
Requirements of a Scientific Hypothesis
Why Does Sugar Affect the Freezing Point of Water?
The Effects of Salt on Ice Cubes
What Happens When You Add Ammonium Nitrate to Water?

Dont Go!

We Have More Great Sciencing Articles!