1. What is science and what are scientific theories?
Theory: “A comprehensive explanation of some aspect of nature that is supported by a vast body of evidence… [that]… can be used to make predictions about natural events or phenomena that have not yet been observed.”
Fact: “An observation, measurement, or other form of evidence that can be expected to occur the same way under similar circumstances.”
National Academy of Sciences and Institute of Medicine. (2008). Science, Evolution, and Creationism. Washington D.C.: The National Academies Press.

2. What is science and what are scientific theories?
Theory: “A comprehensive explanation of some aspect of nature that is supported by a vast body of evidence… [that]… can be used to make predictions about natural events or phenomena that have not yet been observed.”
Fact: “An observation, measurement, or other form of evidence that can be expected to occur the same way under similar circumstances.”
National Academy of Sciences and Institute of Medicine. (2008). Science, Evolution, and Creationism. Washington D.C.: The National Academies Press.

3. What is a scientific hypothesis?
All of these students are likely still doing great science, but do students 2, 4, and 5 really understand the underlying mechanisms that make their predictions possible?

4. What is a scientific hypothesis?
Strode, P. K. (2015). Hypothesis generation in biology: A science teaching challenge and potential solution. The American Biology Teacher, In Press.
“The most common way a hypothesis is used in scientific research is as a tentative, testable, and falsifiable statement that explains some observed phenomenon in nature. We more specifically call this kind of statement an explanatory hypothesis. However, as we will see, a hypothesis can also be a statement that describes an observed pattern in nature. In this case we call the statement a generalizing hypothesis.”
Explanatory hypothesis: a tentative, testable, and falsifiable statement that explains some observed phenomenon in nature.
Generalizing hypothesis: a statement that describes an observed pattern in nature.

5. The Intel ISEF Study
How well do students understand the underlying mechanisms driving their phenomena?
Intel ISEF 2006 Indianapolis
In Science… A hypothesis is an explanation for an observation or a generalization about a pattern.
A prediction is a prophecy about an event that is expected to happen in the future.

6. The Hypothetico-deductive strategy of the “Scientific Method”
The “textbook” model
Induction
Future generations of long-legged anoles have shorter legs. The results support the hypothesis.
Alternative Explanation
Females prefer males with shorter legs as mating partners.
Losos, J. B., & Schneider, C. J. (2009). Anolis lizards. Current Biology, 19, R316-R318.
Deduction
Prediction: Future generations of long-legged anoles experimentally placed on twiggy islands will have shorter legs than their ancestors as a consequence of the available habitat.
Twig anole (Anolis valencienni)
Abduction (analogical reasoning)
Hypothesis: Anoles having shorter legs could be an evolved adaptation to twig habitats similar to what has been documented in other species.
Trunk anole (Anolis sangrei)
Observation
Anole lizards with short legs are most commonly found in twiggy habitats

7. 1) False hypotheses can make true predictions.
Induction
Future generations of long-legged anoles have shorter legs. The results support the hypothesis.
Alternative Explanation
Females prefer males with shorter legs as mating partners.
Losos, J. B., & Schneider, C. J. (2009). Anolis lizards. Current Biology, 19, R316-R318.
Deduction
Prediction: Future generations of long-legged anoles experimentally placed on twiggy islands will have shorter legs than their ancestors as a consequence of the available habitat.
Twig anole (Anolis valencienni)
Abduction
Hypothesis: Anoles having shorter legs could be an evolved adaptation to twig habitats similar to what has been documented in other species.
Trunk anole (Anolis sangrei)
Observation
Anole lizards with short legs are most commonly found in twiggy habitats

8. 2) Most students only apply deduction.
Induction
Future generations of long-legged anoles have shorter legs. The results support the hypothesis.
Alternative Explanation
Females prefer males with shorter legs as mating partners.
Losos, J. B., & Schneider, C. J. (2009). Anolis lizards. Current Biology, 19, R316-R318.
Deduction
Prediction: Future generations of long-legged anoles experimentally placed on twiggy islands will have shorter legs than their ancestors as a consequence of the available habitat.
Twig anole (Anolis valencienni)
Abduction
Hypothesis: Anoles having shorter legs could be an evolved adaptation to twig habitats similar to what has been documented in other species.
Trunk anole (Anolis sangrei)
Observation
Anole lizards with short legs are most commonly found in twiggy habitats

9. 3) Violating our Major Assumptions
Induction
Future generations of long-legged anoles have shorter legs. The results support the hypothesis.
Deduction
Prediction: Future generations of long-legged anoles experimentally placed on twiggy islands will have shorter legs than their ancestors as a consequence of the available habitat.
Leg length in anoles is a strongly heritable trait.
Abduction
Hypothesis: Anoles having shorter legs could be an evolved adaptation to twig habitats similar to what has been documented in other species.
Auxiliary Hypotheses
major assumptions

10. Teaching the Hypothesis
Hasler, Arthur D Guideposts of Migrating Fishes. Science 132:
How do returning silver salmon (Oncorhynchus kisutch) find their home stream?
By borrowing (abducting) explanations from other animal taxa, Hasler generated three hypotheses for salmon navigation:
salmon use sight
salmon smell chemicals specific to their home stream
salmon use the Earth’s magnetic field.

11. Teaching the Hypothesis
Lawson, Antone E The Nature And Development of Scientific Reasoning: a Synthetic View. International Journal of Science and Mathematics Education 2:307–338.
Lawson describes Hasler’s hypothetico-deductive reasoning:
Abduction
Deduction

12. Teaching the Hypothesis
Intel ISEF 2012 Projects:
“The hypothesis was that nuchal temperature would be affected by not telling the truth.”
“The hypothesis of this study was that cattle presence would have an adverse impact on the terrestrial salamander population.”
“If tomatoes are completely surrounded by rice, then the tomatoes with the presence of rice will ripen faster than the tomatoes without rice.”
WHY?
What is it about how the world works that allows you to make that prediction?

13. Teaching the Hypothesis
Intel ISEF 2012 Projects:
“I believe that all three corn by-products will be able to be used as effective substitute insulators.”
“I strongly believe that the tip speed ratio of the wind machine will vary directly with the blade angle.”
Science is not belief, but the will to find out.

14. Teaching the Hypothesis
Hypothesis: Fertilizer provides limiting nutrients to plants.
Prediction: If I provide fertilizer to some plants and not to others, then those plants with added fertilizer will grow to be bigger than plants without fertilizer.

15. Teaching the Hypothesis
Encourage students to keep their hypotheses and predictions separate when planning their experiments.

16. Teaching the Hypothesis

17. Teaching the Hypothesis

18. Teaching the Hypothesis

19. Teaching the Hypothesis