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Students who want to find out things as a scientist, will want to conduct a hands-on investigative experiment. While scientists study a whole area of science, each experiment is focused on learning just one thing at a time. This is essential if the results are to be trusted by the entire science community.

In an investigation, students:

  • Ask a testable question
  • Research the topic
  • Make a hypothesis about the outcome based on the research or their own knowledge
  • Design the investigation
  • Conduct the investigation
  • Collect Data
  • Make sense of the data and draw a conclusion
  • Present their findings for peer review

What is a Testable Question?

The key to a good and manageable investigation is to choose a topic of interest, then ask what is called a “testable question.” Testable questions are those that can be answered through hands-on investigation by the student. The key difference between a general interest science question and a testable question is that testable questions are always about changing one thing to see what the effect is on another thing.

Here are some examples of broader science questions and testable questions:

Easy Testable Questions (recommended for elementary level)
Broad Questions (lead to science reports) Testable questions (lead to investigations)
How do plants grow? What amount of water is best to grow tomatoes? or What type of soil is best to grow petunias? or What amount of sunlight is best to grow daffodils?
What makes something sink or float? How well do different materials sink or float in water?
How do rockets work? How does changing the shape of a rocket’s fins change its flight?
How does the sun heat up water? Does the sun heat salt water and fresh water at the same rate?
What happens when something freezes? Do different liquids freeze at the same rate?
What makes cars move? How does the surface on which a car moves affect how fast it goes?
How do batteries work? Which type of battery lasts the longest?
What makes a magnet attract things? Does temperature have an effect on a magnet’s strength?
Why does ice melt? What is the best insulator to keep ice from melting?
More Complex Testable Questions (recommended for middle school level)
Broad Questions (lead to reports) Testable questions (lead to investigations)
How do lubricants work? Which combination of lubricants will work best on a bicycle wheel?
What can affect animal behaviors? What is the effect of a low-level electrical field on the movement of fruit flies?
What happens when water expands as it freezes? How much force is needed to keep water from expanding as it freezes?
What is soap? Which detergent removes stains the best?
What is bread mold? What conditions keep bread mold from growing on bread?
What do birds eat? What type of food and feeder will attract the most cardinals?
  • Once your student has identified a testable question, have her validate the question: Validate Topic