1. Hypothesis Generation in Science Colorado Science and Engineering Fair, April 7, 2016 Paul Strode, Fairview High School, Boulder, Colorado

2. The Problem Intel ISEF 2006 Indianapolis We know… 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. An ISEF Student Project Board

3. Why is this a Problem? Intel ISEF 2006 Indianapolis We need to help students understand and be able to communicate the natural mechanisms that underlie their investigations. An ISEF Student Project Board

4. What is a scientific hypothesis? Hypothesis! Prediction! Hypothesis

5. Intel International Science and Engineering Fair Survey of 1,864 Student Projects Over 8 Years 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. The Intel ISEF Study

6. Percent Misunderstanding 58% (n = 76) 13% (n = 186) The Intel ISEF Study

7. Percent Misunderstanding 37% (n = 59) 58% (n = 76) 13% (n = 186) The Intel ISEF Study

8. Percent Misunderstanding 13% (n = 186) The Intel ISEF Study

9. State Science Tests Question on the 2012 Colorado Transitional Assessment Program 7. Which statement might be the hypothesis in an experiment? A. During the experiment, all patients will report at the same time. B. The results showed that the control drug was as effective as the experimental drug. C. Patients who receive the experimental drug will improve faster than those who do not. D. The experimental drug and the control drug look and taste the same.

10. My Daughter’s Fourth Grade Class

11. The Hypothetico-deductive strategy of the “Scientific Method” The “textbook” model Abduction (analogical reasoning) Explanatory Hypothesis: Anoles having shorter legs is an evolved adaptation to twig habitats similar to what has been documented in other species. 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. 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. Twig anole (Anolis valencienni) Trunk anole (Anolis sangrei) Losos, J. B., & Schneider, C. J. (2009). Anolis lizards. Current Biology, 19, R316-R318. Observation Anole lizards with short legs are most commonly found in twiggy habitats Most students only do this.

12. False hypotheses can make true predictions. Abduction Explanatory Hypothesis: Anoles having shorter legs is an evolved adaptation to twig habitats similar to what has been documented in other species. 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. 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. Twig anole (Anolis valencienni) Trunk anole (Anolis sangrei) Observation Anole lizards with short legs are most commonly found in twiggy habitats Losos, J. B., & Schneider, C. J. (2009). Anolis lizards. Current Biology, 19, R316-R318.

13. Abduction Explanatory Hypothesis: Anoles having shorter legs is an evolved adaptation to twig habitats similar to what has been documented in other species. 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. Induction Future generations of long-legged anoles have shorter legs. The results support the hypothesis. Auxiliary Hypotheses major assumptions Leg length in anoles is a strongly heritable trait. Violating our Major Assumptions

14. The Solution: help students understand what hypotheses are and how to identify them. Strode, P. K. (2015). Hypothesis generation in biology: A science teaching challenge and potential solution. The American Biology Teacher 77:500-506. “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. Freedom!!

15. Raastad, T., A. T. Hastmark, & S. B. Strømme (1997). Omega ‐ 3 fatty acid supplementation does not improve maximal aerobic power, anaerobic threshold and running performance in well ‐ trained soccer players. Scandinavian Journal of Medicine & Science in Sports, 7:25-31. The Solution: help students understand what hypotheses are and how to identify them.

16. Raastad, T., A. T. Hastmark, & S. B. Strømme (1997). Omega ‐ 3 fatty acid supplementation does not improve maximal aerobic power, anaerobic threshold and running performance in well ‐ trained soccer players. Scandinavian Journal of Medicine & Science in Sports, 7:25-31. Generalizing Hypothesis Explanatory Hypothesis The Solution: help students understand what hypotheses are and how to identify them. Not so difficult to test Difficult to test

17. Generalizing Hypothesis: The height of the tuft of the plant is proportional to the height of the entire plant. The Solution: help students understand what hypotheses are and how to identify them.

19. Observation Some traits skip generations and appear in new combinations in later generations. Gregor Mendel 1856: Crossing Pea Plants (Pisum sativum) The Solution: help students understand what hypotheses are and how to identify them.

20. Observation Some traits skip generations and appear in new combinations in later generations. Generalizing hypothesis (immature law) Forms of traits become segregated from each other during sex cell formation and different traits sort independently. Explanatory hypothesis (immature theory) The hereditary material is particulate in nature, not fluid. Prediction Additional observations continue to confirm generalizing hypothesis. Additional experiments continue to confirm explanatory hypothesis. Law Segregation Independent Assortment can be explained by Theories can provide explanations for laws but can never become laws. Theory Chromosomal Basis of Inheritance The patterns of segregation of forms of genes and different genes sorting independently of each other should be observed across additional traits and in additional species Monohybrids should produce offspring in a 3:1 ratio and dihybrids should produce offspring in a 9:3:3:1 ratio

21. Helping students identify their hypotheses “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? Intel ISEF 2012 Projects:

22. Especially, do not let them do this: 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.

23. Teaching the Hypothesis Observation of Goldenrod (Solidago sp.)

24. Teaching the Hypothesis Goldenrod Gall Fly (Eurosta solidaginis)

25. Teaching the Hypothesis Observation

26. Teaching the Hypothesis Generalizing Hypothesis: The presence of galls on a goldenrod plant is associated with more branches on the plant. Prediction: If I randomly survey 20 goldenrod plants with galls and 20 without galls, there will be significantly more branches on the plants with galls than on the plants without galls. Explanatory Hypothesis: Tissue damage to the goldenrod plant from the galls stimulates the plants to form more branches.

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

28. Teaching the Hypothesis

29. Research Question: What is the effect of exercise on heart rate? Observations of patterns: It seems that when this group of people exercises, all of their heart rates increase. Generalizing Hypothesis/Description of the pattern: Physical activity increases heart rate. (tentative and testable; controlled test?) Prediction: Subjects who exercise vigorously for two minutes will have significantly higher heart rates than when they started and will also have significantly higher heart rates than a resting treatment group. Planned test/Independent variable Specific, measurable dependent variable

30. Teaching the Hypothesis Pattern confirmed. Explanatory hypothesis? Candidate Explanation: Increased exercise increases carbon dioxide production and lowers blood pH which in turn stimulates the heart to beat faster, thus removing excess carbon dioxide and bringing blood pH back to normal.

31. Take Home Messages 1.As science teachers, we are in the business of teaching the Nature of Science, which often begins with correct hypothesis writing and testing. 2.Misuse of “hypothesis” is a problem throughout the profession. 3.Hypothesis writing can be challenging, but is an essential tool for keeping students (and scientists!) focused on the natural patterns and mechanisms that underlie their investigations.