Scientific Methods

1. 001b Scientific Methods

2. The nature of science Science: A systematic process for learning about the world and testing our understanding of it The accumulated body of knowledge that results from a dynamic process of observation, testing, and discovery Science is essential: To sort fact from fiction Develop solutions to the problems we face

3. Global Warming Fact or Fiction?

4. Science as a Way of Knowing Pure Science- pursuit of knowledge Applied Science- search for practical uses of scientific knowledge Pain relief in terminal cancer patients tetradoxin

5. Scientists test ideas Two Primary Approaches to Science Hypothesis-driven or experimental science. Discovery or observational science.

6. Hypothesis-Driven Studies

7. Discovery/Observational Studies

8. Characteristics of Scientific Explanations Science is empirical. It relies on observation and experience. The phenomenon studied must be measurable. Phenomenon that cannot be measured: Is this painting beautiful? Does God exist? It must be consistent with known natural laws and well-established, well-documented existing theories. It must be derived objectively from independently confirmable observations. All scientific knowledge must be regarded as tentative.

9. Scientific statements must be testable and reproducible (i.e., valid & reliable). Hypothesis:The fibropapilloma virus causes tumors in green sea turtles. Hypothesis: Hermatypic corals exposed to temperatures above 36oC expel their symbiotic zoothanthellae. Hypothesis: Naval explosions at the thermocline layer cause hearing loss in whales. Hypothesis: Ulua are better predators.

10. Discovery or Observational Science Some Scientific Questions Can’t Be Answered By Experimentation Discovery or observational science is still science; falsifiable hypotheses based on natural phenomenon are proposed to best account for observations.

11. The Scope and Limitations of Science • Science acquires knowledge through examination of falsifiable hypotheses based on natural phenomena. • This sets a limit on science; science cannot speak directly to such issues as morality or religion. • The domain and limit of science are often misunderstood.

12. Scientific Method A way to answer questions Must be testable & repeatable, i.e., validity and reliability • Deductive Reasoning- general to specific • reasoning from general theories to account for specific experimental results • (theory-data collection-analysis) • Inductive Reasoning- specific to general • reasoning from specific observations and experiments to more general theories (data collection-analysis-theory)

13. Lost at Sea January1992 in the North Pacific

14. Rubber Duckies and Ocean currents. • Jim Ingram (NOAA scientist)- offered a reward • He graphed and studied the data as it came in. • Hypothesis: ocean currents were moving the ducks in about the same speed and direction that the currents were going!

15. Toy trek Researchers expect some 29,000 bath toys lost at sea in 1992 to make the ice-covered trek over the North Pole and to the North Atlantic by this summer.

16. The scientific method A technique for testing ideas • Observations • Question • Formulate Hypothesis • Conduct Experiment • Analyze Results • Conclusions • Discussion

17. Testing predictions Experiment: an activity that tests the validity of a hypothesis Variables: conditions that can be manipulated and/or measured Independent variable: a condition that is manipulated Dependent variable: a variable that is affected by the manipulation of the independent variable Controlled experiment: one in which all variables are controlled Control: the unmanipulated point of comparison Treatment: the manipulated point of comparison Data: information that is generally quantitative (numerical)

18. Experiments test the validity of a hypothesis Manipulative experiments yield the strongest evidence Provides the strongest type of evidence Reveal causal relationships: changes in independent variables cause changes in dependent variables But many things can’t be manipulated: long-term or large-scale questions (i.e., global climate change) Natural experiments show real-world complexity Only feasible approach for ecosystem or planet-scale Results are not so neat and clean, so answers aren’t simply black and white

19. Testing predictions Experiment: an activity that tests the validity of a hypothesis Variables: conditions that can be manipulated and/or measured Independent variable: a condition that is manipulated Dependent variable: a variable that is affected by the manipulation of the independent variable Controlled experiment: one in which all variables are controlled Control: the unmanipulated point of comparison Treatment: the manipulated point of comparison Data: information that is generally quantitative (numerical)

20. Experiments test the validity of a hypothesis Manipulative experiments yield the strongest evidence Provides the strongest type of evidence Reveal causal relationships: changes in independent variables cause changes in dependent variables But many things can’t be manipulated: long-term or large-scale questions (i.e., global climate change) Natural experiments show real-world complexity Only feasible approach for ecosystem or planet-scale Results are not so neat and clean, so answers aren’t simply black and white

21. Ben Franklin & the Gulf Stream Observation: Question: 1786 Hypothesis: Test hypothesis: Analyze Results: Draw Conclusion: 1996

22. Coral Mapping (Molokai)

23. Do sponges affect mangrove root growth? Mangrove Study

24. Mangrove Study Select a large sample size Randomly divide the sample into 2 groups Treat the groups equally in all ways but one Observe or make measurements Compare results

25. Paine’s study on Pisaster and blue mussels What effect does starfish removal have on community structure? mussels (Mytilus) Pisaster barnacles chiton limpet

26. Paine’s study on Pisaster and blue mussels Keystone Species

27. What is difference between hypothesis, theory & law? Hypothesis - “an educated guess”; a tentative explanation of phenomena. Theory - a widely accepted explanation of natural phenomena; has stood up to thorough & continual testing. Law - a statement of what always occurs under certain conditions.

28. Theories Cell Theory Evolution

29. Laws Physics, Chemistry, Math- Lots!!!! Biology: Mendelian Inheritance

30. The Blind Men and the Elephant

31. The Blind Men and the Elephant (Saxe; 1816-1887) I. It was six men of Indostan To learn much inclined, Who went to see the elephant (Though all of them were blind), That each by observation Might satisfy their mind. II. The First approached the elephant, And happened to fall Against his broad sturdy side, At once began to bawl: “Bless me!—but the Elephant is very like a wall!”

32. III. The Second, feeling of the tusk , Cried, “Ho!—what have we here So very round and smooth and sharp? To me ‘t is mighty clear This wonder of an Elephant Is very like a spear!” IV. The Third approached the animal, And happening to take The squirming trunk within his hands, Thus boldly up and spake: “I see,” quoth he, “the Elephant Is very like a snake!”

33. V. The Fourth reached out his eager hand, And felt about the knee. “What most this wondrous beast is like Is might plain’” quoth he; “‘T is clear enough the Elephant Is very like a tree!” VI. The Fifth, who chanced to touch the ear, Said, “E’en the blindest man Can tell what this resembles most; Deny the fact who can, This marvel of an Elephant Is very like a fan!”

34. VII. The Sixth no sooner had begun About the beast to grope, Than seizing on the swinging tail That fell within his scope, “I see,” quoth he, “the Elephant Is very like a rope!” VIII. And so these men of Indostan Disputed loud and long, Each with his own opinion Exceeding stiff and strong, Though each was partly in the right, And all were in the wrong!

35. Moral. So, oft in these theological wars The disputants, I ween, Rail on in utter ignorance Of what each other mean, And prate about an elephant Not one of them has seen!

36. The Blind Men and the Elephant, Part 2, I. They talked, those men from Indostan While standing at the door, Of elephants and how they looked (This talk was such a bore!), At last they agreed that the knowledge gained Required something more. II. Perhaps each one in his own way, Did learn a bit Of the beast’s elusive mystery, But just a part of it With work, they thought, that they might see The puzzle pieces fit.

37. III. ‘Twas obvious to all of them For learning to progress, That they must share in what they found— Jointly sort out the mess. And seek to fully understand Elephants, more or less. IV. Some worked alone and some in teams, In both the field and lab. Models were made: some soft, some hard Some good, some pretty bad. But when they pooled the useful work, And truth they made a grab.

38. V. They checked each other’s methods out, Some kept, some put asunder. To use the ones which passed the test Reduced the chance of blunder. Then they’d trust what they had learned Of elephants’ fine wonders. VI. They made great strides in what they knew Of the nature of the beast. Of what and where and how and why They knew much more at least. For blind men learned how best to learn And vision soon increased!

39. Inquiry • What is the difference between a hypothesis, theory and law? • Can a theory ever be proven? • In the mangrove study, what is the dependant variable? • State Ben Franklin’s hypothesis. • In Paine’s study on Pisaster, what role did blue mussels play?

40. QUESTION: Review Which is the correct order of the scientific method? Observation, hypothesis, testing, results Hypothesis, observation, testing, results Observation, testing, results, hypothesis observation, testing, hypothesis, results

41. QUESTION: Interpreting Graphs and Data What happens if test results reject a hypothesis? The scientist formulates a new hypothesis. It shows the test failed. The scientist should be fired. The scientist used faulty data .