2 The Scientific Method …lots and lots and lots of math. 2/18/1996.

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The Scientific MethodThe Scientific Method

…lots and lots and lots of math.2/18/1996

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Goal

• What is science?• What is the scientific method?• Does the scientific method work?• What is not a scientific argument.• Does astrology follow the scientific

method?

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What is science?

• Science is a tool to understanding the Universe.

• You see something happen, you ask why?• You make a model (or hypothesis) that

explains what you see.• A scientific model must do two things:

– Explain what is seen.– Predict what will happen accurately.

• How do you know if your model is right?

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What is science?

• Science is a tool.• Medicine: “I have high cholesterol, what

should I do?”– Take cholesterol lowering medication.– Consult your astrologer.– Pray to the god Baal and sacrifice a goat.

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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

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Medical Science

Scientific Method

High Cholesterol

Observation Patient has high cholesterol

Hypothesis (prediction)

Certain chemicals may dissolve cholesterol deposits.

Test Give 100 patients these chemicals, give 100 patients placebo.

Observe result Same number of patients lower their cholesterol as placebo patients.

Revise hypothesis?

Try different amounts of chemicals.

New test? Re-run medical test. Observe results.

Scientific Theory

Lipitor reduces cholesterol.

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Everyday Science

Scientific Method Car Repair

Observation Engine won’t turn over.

Hypothesis (prediction)

Predict battery is dead.

Test Replace battery.

Observe result Engine now turns over.

Revise hypothesis? Not needed.

New test? Not needed.

Scientific Theory Cars won’t work without a fully charged battery.

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Everyday Science

Scientific Method Making Spaghetti Sauce

Observation Spaghetti sauce should be red.

Hypothesis (prediction)

Use tomato sauce.

Test Heat pot of tomato sauce.

Observe result Taste the sauce - bland.

Revise hypothesis?

Use tomato sauce and garlic!

New test? Add garlic, taste - not so bland.

Scientific Theory The Final Recipe.

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Food Science

• Throwing something together Hypothesis

• Your grandmother’s time-tested recipe Scientific Theory.

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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”

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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.

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Non-scientific Theories

• Make no predictions• Un-testable• Can’t be falsified• 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).

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Non-scientific Theories

• Car won’t work? Aliens drained the battery.

• Spaghetti is bland? You were meant to eat bland food.

• Car won’t work? 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.

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Non-scientific Theories

• The chain of events needed for life to arise are too complicated to have happened by chance, a divine intelligence must therefore have caused life to arise (Intelligent Design).

• Face on Mars.

Viking Orbiter (1976) Mars Global Surveyor (1998)

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Falsification

• A real Scientific Theory tells you what observations are necessary to falsify it.– Not so proponents of:

• Face on Mars• Moon Hoax• Intelligent Design• Astrologers

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Astrology Tests

• What test would falsify astrology?

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Astrology and the President

(TIME, May 16, 1988) -- “The First Lady dabbled in astrology as far back as 1967. In 1981 [Joan] Quigley made Nancy a believer …. And from then on, no presidential public appearance was slated without the Friend's say-so. To this day, Nancy's Friend continues to influence the President's schedule. For the Reagan-Gorbachev Washington summit, she cast the charts of both men and determined

that 2 p.m. on Dec. 8, 1987, was the most propitious moment for them to sign the intermediate-range nuclear forces treaty. At Nancy's behest, the entire summit was built around that hour. For the upcoming Moscow summit, Gorbachev's chart (he is a Pisces) has been recast alongside Reagan's (Aquarius).”

“[Former White House Chief of Staff, Donald] Regan and others make a compelling case that in 1986 and 1987 astrological influence dramatically reduced the presidency's effectiveness, at least partly, by keeping Ronald Reagan under wraps for much of the time. Nancy's intrusions in the scheduling process, Regan said in an interview with TIME last week, ‘began to interfere with the normal conduct of the presidency.’”

(TIME, May 16, 1988)

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Homework #2Homework #2

• For Thursday 9/12:• Read Bennett chapter 1.1 – 1.2

– (B1.1 – 1.2 on Physics 103 lecture web page)

• For Monday 9/16:• Read Ty7 and B6.1 – 6.3, B7.1 – 7.5• Do B6: Review Questions 8, 9, and

Problems 1, 2• Do B7: Problems 3, 5, 9, 10