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Thinking Like a Scientist Activity 4

Inventing hypotheses or theories to imagine how the world works and then figuring out how they can be put to the test of reality is as creative as writing poetry, composing music, or designing skyscrapers.

--F. James Rutherford and Andrew Ahlgren

Seeking Solutions


Students will experience the importance of forming and testing hypotheses.

About the Activity

The process for producing knowledge in science is to first observe a phenomenon, and then to construct a hypothesis to explain those observations. The hypothesis is based on both previous and current knowledge and research. It is possible that more than one hypothesis will explain a set of observations. It is also just as possible that another hypothesis explains the phenomenon better. To be useful, a hypothesis must be testable--that is, scientists must be able to create and conduct experiments that test the underlying assumptions of the hypothesis. Testing the hypothesis through research and experimentation helps a scientist gather evidence that his or her hypothesis is valid.

In this activity, students will be given information about several phenomena. Students will choose one phenomenon, and form hypotheses to explain the situation. They will then design an experiment to test one or more of their hypotheses.


For the class:

  • Reference materials
For each student


Duplicate the handout to distribute to students. Collect reference materials about the subjects listed on the handout.


  1. Distribute the handout to the students. Explain that the students should read through the observations on the handout and then choose one scenario that interests them.
  2. Ask students to use the reference materials to collect as much information about the problem as possible. They might also research any previous experiments that have studied the problem. Remind students that they can use the library or perform on-line searches.
  3. Why must a hypothesis be testable? Why is it important to clearly outline the materials and procedures you would use to test your hypothesis?
  4. Next have students brainstorm possible explanations for the observations, and use the explanations to form several possible hypotheses. Have students record their hypotheses and then have them select one from the list to test.
  5. Have students research information on ways to test their hypothesis. Then have them write one or more test procedures. Tell students that although they do not actually have to perform the experiment at this time, at least one of the experiments they design should use materials that are readily available at school or at home. Remind students to indicate the materials they would use, the step-by-step procedures they would follow, and the type of data they would collect and record.

Discussion Questions:

  1. Compare the hypotheses that were proposed for each problem. Were all the hypotheses for a problem the same? Why or why not? Did one hypothesis seem more likely to fit the observations than another?
  2. Compare the experiments that were designed to test each hypothesis. Are there any similarities between the experiments? If so, what are they?
  3. Why must a hypothesis be testable? Why is it important to clearly outline the materials and procedures you would use to test your hypothesis?
  4. Suppose that you performed the experiment you outlined and the results turned out to be the opposite of what you expected. How could this information be helpful? What would you do next?

Handout 2: Seeking Solutions

Activity 5: Just the Facts

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