1. Use the ACT passage on your desk to answer the following questions: 1. About which of the following points do the two theories differ? A. Movement of tectonic plates across the Earth’s surface B. Density of hot mantle rocks C. Existence of convection currents in the Earth’s mantle D. Role of mantle convection in tectonic plate movement 2. How would supporters of Slab Pull Theory explain the documentation of seafloor spreading cited in Mantle Convection Theory? A. Seafloor spreading directly causes tectonic plate movement and slab subduction. B. Seafloor spreading does not exist. C. Seafloor spreading and slab subduction simultaneously exert moving forces on tectonic plates. D. Seafloor spreading exists, but only as a result of slab subduction. Catalyst: 9/14/10

2. Objective SWBAT… List and describe the steps of the scientific method Agenda -Catalyst (7) -Scientific method Powerpoint notes (25) -Scientific method sequencing (15) Homework Section 2 Review, page 53, even numbers

3. The Scientific Method involves a series of steps that are used to investigate a natural occurrence.

4. The Scientific Method 1.Observe an event. 2.Develop a model (or hypothesis) which makes a prediction. 3.Test the prediction (experiment). 4.Observe the result. 5.Revise the hypothesis. 6.Repeat as needed. 7.Publish/Present* model test

5. Observations Gathered through your senses Gathered through your senses A scientist notices something in their natural world A scientist notices something in their natural world

6. Hypothesis A suggested solution to the problem. A suggested solution to the problem. Must be testable Must be testable Sometimes written as If…Then… statements Sometimes written as If…Then… statements Predicts an outcome Predicts an outcome

7. Experiment to test the hypothesis Develop and follow a procedure to test the hypothesis. Include a detailed materials list. The outcome must be measurable (quantifiable).

8. Scientific Experiments Follow Rules An experimenter changes one factor and observes or measures what happens.

9. Variables The factor that is changed is known as the independent variable. The factor that is measured or observed is called the dependent variable.

10. The Control Variable The experimenter makes a special effort to keep other factors constant so that they will not affect the outcome. The experimenter makes a special effort to keep other factors constant so that they will not affect the outcome. Those factors are called control variables. Those factors are called control variables.

11. What is the Purpose of a Control? Controls are NOT being tested Controls are used for COMPARISON

12. Control Group The control group is exposed to the same conditions as the experimental group, except for the variable being tested.

13. Example of Controls & Variables For example, suppose you want to figure out the fastest route to walk home from school. You will try several different routes and time how long it takes you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

14. What are the Variables in Your Experiment? Varying the route is the independent variable Varying the route is the independent variable The time it takes is the dependent variable The time it takes is the dependent variable Keeping the same walker throughout makes the walker a control variable. Keeping the same walker throughout makes the walker a control variable.

15. One more thing… it is best to make several trials with each independent variable.

16. Data Results of the experiment May be quantitative (numbers) or qualitative (descriptive)

17. Data Must be organized Can be organized into charts, tables, or graphs Must be analyzed to determine whether to accept or reject hypothesis

18. Conclusion Include a statement that accepts or rejects the hypothesis. Make recommendations for further study and possible improvements to the procedure.

19. Determine Limitations to Revise Scientists look for possible flaws in their research They look for faulty (inaccurate) data They look for experimental error or biases They decide on the validity of their results They make suggestions for improvement or raise new questions

20. Retest In order to verify the results, experiments must be retested.

21. 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.

22. Everyday Science Scientific MethodMaking Spaghetti Sauce ObservationSpaghetti sauce should be red. 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.

23. Theories A theory is a highly successful hypothesis. All theories make predictions which can be tested. Any scientific theory can be falsified and is subject to change as our ability to make tests, or make observations of a test’s results, improves with time.

24. Non-scientific Theories Make no predictions Cannot be tested Cannot be falsified

25. Scientific Method Sequencing Take out your “Record Sheet” I will pass out envelopes with cards inside with the steps of experiments Put the cards into the correct order ( Question, Hypothesis, Experiment, Data, Conclusion) Write the letter of the card which fits each part for that experiment (e.g., headache holly goes in the first list) When finished, shuffle the cards. Swap envelopes until you finish all 6 experiments. Remember… Homework: pg 53 questions, even only