Scientific Method

1. Scientific Method

2. Steps in the Scientific Method • Observation • Hypothesis • Experiment • Data Collection • Conclusion • Retest

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

4. Observations • An exampleof an observation might be noticing that many salamanders near a pond have curved, not straight, tails

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

6. Hypothesis • An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

7. Experiment • A procedure to test the hypothesis.

8. Experiment Variable – factor in the experiment that is being tested

9. Experiment A good or “valid” experiment will only have ONE variable!

10. Controls and Variables

11. Scientific Experiments Follow Rules • An experimenter changes one factor andobserves or measureswhat happens.

12. The Control Variable • 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.

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

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

15. 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.

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

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

18. Valid Experiments

19. Remember: To be a Valid Experiment: • Two groups are required --- the control & experimental groups • There should be only onevariable

20. Data • Results of the experiment • May be quantitative (numbers) or qualitative (words)

21. Data • Must be organized • Can be organized into charts, tables, or graphs

22. Conclusion • The answer to the hypothesis based on the data obtained from the experiment

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

24. Recap: To Solve a Problem 1)Identify a Problem 2) State Observations about the problem 3) Form a Hypothesis about the problem (if…then…) 4) Design an Experiment to test the hypothesis 5) Collect Data 6) Form a Conclusion 7) Retest

25. Review… No need to write these slides down in notebook

26. In what part of the scientific method do you write an investigative question? • Identify the problem

27. What are the two parts of the analysis? • Create a graph and write a summary

28. A conclusion needs to support orrepudiate your _____________. • hypothesis

29. How do we record data in an experiment? • data tables (rows and columns)

30. The independent variable may change the ________ variable in an experiment. • dependent

31. When we are finished with our experiments we ____________ our findings. • communicate

32. What do we call informationcollected during the experiment? • Data

33. The procedure is a list of__________ that describes the experiment. • Steps

34. How many times should an experiment be repeated? • Many times to help average issues such as human error

35. Variables that are kept the same are called ___________ • controls