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

Goal What is the scientific method? Does the scientific method work? Why does a scientific method need to be repeatable? What is the term for a hypothesis that has been repeatedly proven? What is not a scientific argument?

What is science? Science is a tool. Medicine: “I have high cholesterol, what should I do?” –Take cholesterol lowering medication. –Consult your horoscope. –Pray to the god Baal and sacrifice a goat.

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

Medical Science Scientific MethodHigh Cholesterol ObservationMr. Chunky has high cholesterol Hypothesis (prediction) Certain medicines may dissolve cholesterol deposits in his veins. TestGive 100 patients these chemicals, give 100 patients a placebo (fake). Observe resultNo difference between medicine group and placebo group. Revise hypothesisTry a different combo of medicines. New testRe-run tests. Observation: new medicine combo makes cholesterol go down. Scientific TheoryLipitor reduces cholesterol.

Everyday Science Scientific MethodCar Repair ObservationEngine won’t turn over. Hypothesis (prediction)Predict battery is dead. TestReplace battery. Observe resultEngine now turns over. Revise hypothesis?Not needed. New test?Not needed. Scientific TheoryCars won’t work without a fully charged battery.

Everyday Science Scientific MethodMaking Spaghetti Sauce ObservationSpaghetti sauce uses tomato sauce. Hypothesis (prediction)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.

Food Science Guessing at a recipe = Hypothesis Your grandmother’s time-tested recipe = Scientific Theory

Repeatability What does the word “Theory” mean to you? “A conjecture; guess” (Webster’s Dictionary) What does the word THEORY mean to a scientist? A model which has been proven by repeated tests and observations A successful scientific theory is repeatable. –By anyone! DISCUSS: Why must science be repeatable? What does it mean if something cannot be repeated? What is the benefit of having all scientists use the scientific method?

Scientific Theories and Laws Both: -based on tested hypotheses -supported by a large body of data -agreed upon by the vast majority of scientists -could be shown to be wrong at some time if there is consistent data to suggest it’s wrong

Scientific Theories and Laws So what is the difference between a Theory and a Law? Theory: an explanation of a set of observations based upon tested hypotheses and repeated many times by separate researchers ex: “Theory of Evolution” Law: a statement of fact that describes an action or set of actions. It is accepted to be universal, and can sometimes be expressed in terms of a single mathematical equation ex: “Newton’s 2 nd Law of Motion: F=M x A

Non-scientific Theories Make no predictions Un-testable Can’t be proven as false…no way to prove as true or false.

Non-scientific Theories Car won’t work?  Aliens drained the battery. Seasons change?  Magic Season Powder. Car won’t work?  The 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.

Non-scientific Theories 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). Face on Mars. Viking Orbiter (1976)Mars Global Surveyor (1998)

Lab Report Format Title Question: (always use correct punctuation) Hypothesis: I think...because….. Materials: (shopping list. Include everything.Yes, Everything.) Procedure: (number your procedure steps) Data: (data tables, graphs, numbers) Conclusion: (My hypothesis was ….. Talk about your numbers, your findings, your conclusions)

Lab Report Format Labels should stand out along left edge, like this: Question: How many drops of water can I fit on a penny? Hypothesis: I think I can fit ___ drops of water, because the penny is small. Materials: dropper, water, beaker, penny, paper towel Procedure: 1) ….. 2) …. Data: I was able to fit ___ drops of water on the penny Conclusion: My hypothesis was wrong. I was able to fit more drops on the penny than I thought, because the water _____.

Astrology Tests What test would prove a horoscope true or false?

HW Create a scientific test to prove a horoscope is not real science.