How to Write a Testable Question Tamara Helfer, 2012 Sequoia Science Explorations

Sometimes scientists just like to explore…

Exploring or making observations often makes scientists curious about specific questions. To answer these specific, testable questions, most scientists carry out investigations using The Scientific Method.

What is a “Testable Question?” A testable question asks about objects, organisms, and events in the natural world.

What is a “Testable Question?” A testable question is one that can be answered by designing and conducting an experiment.

What is a “Testable Question?” A testable question can be answered by collecting and analyzing evidence that is measurable.

What is a “Testable Question?” A testable question relates to scientific ideas rather than personal preference or moral values.

A testable question is always about changing one thing to see what the effect is on another thing. What is a “Testable Question?”

A Testable Question has two parts: An independent variable A dependent variable

Testable Question Format What is the effect of the ___ on the ___? I.V.D.V. Independent Variable Dependent Variable

Sample Testable Question What is the effect of the height of a ramp on the speed of a car going down the ramp?

What is the independent variable? What is the effect of the height of a ramp on the speed of a car going down the ramp? height of a ramp

What is the dependent variable? What is the effect of the height of a ramp on the speed of a car going down the ramp? speed of a car

Another Testable Question What is the effect of the amount of light on the growth rate of plants? Identify the INDEPENDENT variable. amount of light Identify the DEPENDENT variable. growth rate of plants

Another Testable Question What is the effect of the temperature of water on the time it takes a sugar cube to dissolve? Identify the INDEPENDENT variable. temperature of water Identify the DEPENDENT variable. time it takes a sugar cube to dissolve

Is this a Testable Question? What makes plants grow best? No –This question is too general.

Think of a cause and an effect related to your general question. What makes plants grow best? In this case, you can change something to affect something about how a plant grows. Turn a General Question into a Testable Question

What makes plants grow best? Examples: -Amount of water -Amount of light -Soil type What are examples of things you can change?

What makes plants grow best? Examples: -Height of plant -Speed of growth What specific effects can you look for?

Finally, plug the cause and the effect into the format… “What is the effect of the ____ on the ____?” The cause (I.V.) goes in the first blank, and the effect (D.V.) goes in the second blank. What is the effect of the type of soil on the height of a plant?

Here’s another example... Is it Testable? How does a paper airplane fly? No –This question is too general.

Let’s Make the Question Testable! Decide what you are going to change (independent variable). Examples: -Size of the plane -Style of the plane -Type of paper

Decide what you are going to measure (dependent variable). Examples: -Distance the plane will fly -Length of time the plane stays in the air Let’s Make the Question Testable!

Make the Question Testable Now select one independent variable and one dependent variable Put them together to create the testable question: What is the effect of the type of paper on the distance a paper airplane flies?

Final Thoughts Keep your experiment simple and clear. Check out the Media Center or our web links for ideas. Don’t wait! Some projects take time to do.