1. 2 The Scientific Method Pushing back the frontiers of human knowledge.

2. 2 Goals What is science? What is the scientific method? Does the scientific method work? What does the scientific method assume? What is not a scientific argument.

3. 2 Science as a tool Science is a tool for answering why and how. “I have high cholesterol, what should I do?” –Take cholesterol lowering medication. –Consult my astrologer. –Pray to the god Baal and sacrifice a goat. How do you choose what to do? What is your criteria for the “best” solution?

4. 2 Tests and Theories Science is a tool for telling you what works! How do you know if your theory (idea, model, hypothesis) is right? –You can test it! –I make a claim, you can test that too. A scientific theory must do two things: –Explain what is seen. –Predict what will happen in the future. Implicit predictions Explicit predictions

5. 2 The Scientific Method 1.Observe an event. 2.Develop a model (or hypothesis) which makes a prediction. 3.Test the prediction. 4.Observe the result. 5.Revise the hypothesis. 6.Repeat as needed. 7.A successful hypothesis becomes a Scientific Theory. model test

6. 2 Medical Science Scientific MethodHigh Cholesterol ObservationPatient has high cholesterol Hypothesis (prediction) Certain chemicals may dissolve cholesterol deposits. TestGive 100 patients these chemicals, give 100 patients placebo. Observe resultSame number lower their cholesterol as placebo patients. Revise hypothesis?Try different combo of chemicals. New test?Re-run medical test. Observe results. Scientific TheoryLipitor reduces cholesterol.

7. 2 Everyday Science Scientific MethodMaking Spaghetti Sauce ObservationSpaghetti sauce should be red. Hypothesis (prediction)Maybe try a tomato sauce. TestHeat pot of tomato sauce. Observe resultTaste the sauce - bland. Revise hypothesis?Use tomato sauce and garlic! New test?Add garlic, taste - not so bland. Scientific TheoryThe Final Recipe.

8. 2 A Theory’s Power A successful theory means: –Applies to the future (the prediction) –You don’t have to keep doing the test. Example: –Lipitor: No more trials –Recipe: No more trial and error Does your daily example satisfy this requirement?

9. 2 Reproducibility Anyone must be able to reproduce the claims of your result. –Cookbooks (In)Famous examples: –Cold Fusion –“Wow!” SETI signal The conservative nature of Science.

10. 2 Textbook vs. Newspaper Theories “Textbook” Theory: –Well reproduced (decades to centuries) Sun centered solar system Theory of gravity “Newspaper” Theory: –Tentative to strong support (possibly no reproduction) String Theory Dark matter Often mixed together in media and public minds

11. 2 Recap: Theories, Guesses, Laws What does the word “Theory” mean to you? “A conjecture; guess” (Webster’s Dictionary) Does it mean the same to a scientist? “A model which has been born out by repeated tests and observation.” Is a Theory less than a Law? “Evolution is just a theory, it is not a fact.” Do Theories “grow up” to be Laws? “Einstein’s Theory of Relativity”

12. 2 Concept Question Which of these statements is true. a.A theory becomes a Law after it has been proven correct. b.A theory becomes a Law if it is supported by the results of enough experiments. c.A Law that is refuted by experimental results becomes just a theory. d.The movement of the Earth around the Sun and the formation of the Universe in the Big Bang are theories. e.We should withhold judgments on theories until they become Laws.

13. 2 Limitations of Science Key to the scientific method is The Test. Q: What can and cannot be tested? Q: What is and is not reproducible? A: Magic, the Divine, matters of faith cannot be tested and are not reproducible. Result: 1.Science is the search for natural or material explanations to the Universe. 2.Science is limited to those questions of which natural or material explanations can be applied.

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15. 2 Assumptions of Science To what questions are natural or material explanations applicable? –God of the Gaps –The unknown versus the unknowable! Are we justified in assuming that natural or material explanations are sufficient to describe the world? –Personal Experience The Universe isn’t random. –The same test done by you, me, yesterday and tomorrow should all give the same result.

16. 2 Theories So: a theory is a highly successful hypothesis. All hypotheses make predictions. All theories make predictions. All theories can be tested. Result: Any scientific theory is subject to change as our ability to make tests, or make observations of a test’s results, improves with time.

17. 2 Concept Test Which of the following DO NOT satisfy the requirements of a scientific theory? a.Objects of different mass fall to Earth with the same acceleration. b.In the case of a very high mass in very small volume, there is a distance from the center inside of which light cannot escape. c.The better a species is adapted to its environment the more likely it is to pass on the ability to survive to its descendents. d.Outside our universe is another universe of which we can have no knowledge. e.The making of leavened bread requires yeast.

18. 2 Non-scientific Theories Make no predictions Un-testable Can’t be falsified

19. 2 Non-scientific Theories Cholesterol too high?  Aliens are clogging your arteries with invisible probes. Spaghetti is bland?  You were meant to eat bland food. Cholesterol too high?  Gods must be angry. Spaghetti is bland?  At the instant of tasting, tongue is transported to alternate dimension where all flavors are rendered nullified. Happens instantaneously.

20. 2 Non-scientific Theories Viking Orbiter (1976)Mars Global Surveyor (1998)

21. 2 Falsification A real Scientific Theory tells you what observations are necessary to falsify it. –Not so proponents of: Face on Mars Moon Hoax Astrologers

22. 2 Concept Test Consider the following theory. Why does it not satisfy the requirements of a scientific theory? “The chain of events needed for life to arise is too complicated to have happened by chance, a divine intelligence must therefore have caused life to arise (Intelligent Design).” a.It contradicts the theory of evolution. b.It makes no prediction which can be tested. c.It assumes there is something we don’t understand. d.It assumes there is a God. e.It doesn’t rely upon any observations.

23. 2 Homework #2 Due Friday 13-Jan: Read Ty12 and Sagan article 1 (Sg1): Science and Hope from Demon Haunted World. Why is belief in science not just a replacement for belief in astrology or religion? One should be skeptical of astrology because: a.It takes power out of the hands of scientists. b.It can’t be tested. c.It has failed when tested. d.It proposes forces that are non-physical. e.It threatens our belief in a knowable universe. Remember the Topic of Confusion!