Chpt8 how to do an experiment
- 1. L.O: students will review how to conduct controlled experiments. Do now: read your “cheat sheet”
- 2. How to design a controlled experiment:
- 3. Diet pill commercials use “before and after” shots as a side by side comparison to show that the pills REALLY work! When they ask if you want to “supersize it”, say NO!!!! before After!
- 4. Scientists conduct controlled experiments as side by side comparisons too!!!!!!
- 5. A controlled experiment ALWAYS has at least TWO groups: an experimental group and a control group.
- 6. BOTH groups are IDENTICAL GROUPS…but • only the ( ). • The . • Sometimes the control group is given a placebo (a fake drug or a sugar pill)
- 7. Control group is identical to Experimental group gets experimental group but DOES the drug or the treatment. NOT get the drug or treatment!
- 8. The two groups are compared to see IF the drug or treatment REALLY works!!!!!!
- 9. a good experiment must have a large number of test subjects, be repeatable & take place for a long time!!!!!!
- 10. Characteristics of a good experiment: 1. Has both an experimental group and a control group. 2. Has many many test subjects. 3. Is repeated many many times. 4. The experiment lasts for long time (weeks, months, years…)
- 11. An old saying says: “A picture is worth a thousand words”….
- 12. Scientists use graphs and tables because they make complicated data, easier to understand. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 13. You MUST be able to read a table and a graph! Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 14. You MUST be able to draw a graph from a data table! Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 15. In many experiments are looking for cause and effect relationships…. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 16. IF one thing CAUSES something ELSE. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 17. Experiments have independent variables and dependent variables: Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 18. independent variables are the cause. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 19. dependent variables are the effect. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 20. experiments are designed to see IF the independent variables causes the dependent variable to happen. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 21. in data tables: the independent variable is ALWAYS the first column Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 22. in graphs: the independent variable is ALWAYS the X-axis Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 23. in graphs: the dependent variable is ALWAYS Y-axis. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 24. you must be able to draw conclusions from tables and graphs. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 25. Now answer 1-20.
- 26. The scientific method:
- 27. The scientific method: The scientific method is a method of designing an experiment.
- 28. A well-designed experiment has the following: • A : written as a question. : • A : (a possible answer to the problem): (NOT as a question). ( ), ( ) : what will be done to prove or disprove the hypothesis. : the collected data. : used to display and help interpret the results. was the experiment , did the results support or refute the hypothesis?
- 29. A valid experiment is one where the data and conclusions support the hypothesis. The hypothesis was valid (correct)!
- 30. Now answer 21- 49
- 31. You MUST know how to draw line graphs. There WILLLLLLLLLL definnnnnntellllly be one on the regents!!!!
- 32. How to draw a line graph, using data from a table: Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 33. 1. Label the X-axis (ALWAYS the independent variable) label the Y-axis (ALWAYS the dependent variable) Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 34. 2. Make an appropriate scale number line for the X-axis. the units MUST be EVENLY spread out! (0,1,2,3,4 …or 0, 2,4,6,8…or 0,5, 10, 15…. Or 0, 10,20,30…or 0.0,0.5,1.0, 1.5, 2.0, 2.5….) Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 35. 3. Make an appropriate scale number line for the Y-axis. the units MUST be EVENLY spread out! (0,1,2,3,4 …or 0, 2,4,6,8…or 0,5, 10, 15…. Or 0, 10,20,30…or 0.0,0.5,1.0, 1.5, 2.0, 2.5….) Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 36. 4. Accurately plot the points. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 37. 5. connect the points. Surround each point with a small circle, square or triangle. Elapsed Time (s) Speed Ms−1) 0 0 1 3 2 7 3 12 4 20 5 30 6 45
- 38. Now answer 50- 82.
- 39. You probably WON’T have to draw a bar graph BUT you must know how to read them!!!!
- 40. Example: predict how much this country’s population will grow in 2003.
- 41. Now answer 83- 108
- 42. Now: complete all the unfinished questions! Make me proud!