Process Skills, Identifying Variables, Writing Hypotheses, and Designing Experiments

1. Process Skills, Identifying Variables, Writing Hypotheses, and Designing Experiments 8-1.1 Design a controlled scientific investigation. recognizesteps appropriate for conducting a controlled investigation 8-1.2 Recognize the importance of a systematic process for safely and accurately conducting investigations. identify ways to safely and accurately conduct an investigation recallconditions necessary for a valid investigation

2. Mystery Footprints Engage

3. Process Skill Review and Practice • Identify each scenario as • Quantitative observation • Qualitative observation • Inference Check for Understanding C.F.U.

4. When I ring the doorbell, no one answered. • Qualitative Observation

5. The hamburger was hot! • Qualitative Observation

6. Urkel must be popular. • Inference

7. The sun set at 7:18 p.m. • QuaNtitative observation

8. That sounded like a mean dog. • Inference

9. Pizza must be his favorite food because he ate a lot. • Inference

10. Look at those clouds! It looks like it’s going to rain. • Inference

11. The beaker contains 200 mL of water. • QuaNtitative observation

12. My mom looks mad. • Inference

13. A gas is formed when I mixed the liquid and solid. • Qualitative observation

14. Inference • Definition: • Explanation for an observation based on past experiences and prior knowledge • Often change with new observation • (remember mystery footprints) • Help explain observations

15. Observation: grass is wet. • Inferences: • It rained. • Sprinkler was on. • Morning dew • Dog urinated!

16. Observation: school fire alarm goes off • Inferences: • School is on fire • Fire drill • Student pulled alarm

17. Observation: student is sitting in the office • Inferences: • ? Check for Understanding C.F.U.

18. Draw inference here

19. Identifying Stepsof the Scientific Method A) _____We bought a block of unsliced cheese on the same day, and it isn’t moldy at all. B) _____ I think that sliced cheese gets moldy faster because people touch it more. C) _____ After five days, both sets of cheese that I touched are moldy. Both sets of cheese that I left alone have no mold. D) _____ I keep four separate sets of cheese in the refrigerator: five slices that I touch once a day; five slices that I leave untouched; five cubes of unsliced cheese that I touch one a day; and five cubes that I leave untouched. E) _____Why is the sliced cheese in the fridge all moldy? F) _____ I was right; touching is the critical factor in making cheese mold. G) _____ There must be something about sliced cheese that makes it more likely to mold.

20. E) Why is the sliced cheese in the fridge all moldy? • Problem

21. A) We bought a block of unsliced cheese on the same day, and it wasn’t moldy at all. • Observation • (qualitative)

22. B) I think that sliced cheese gets moldy faster because people touch it more. • Inference

23. G) If cheese is touched more, then it will mold faster. • Hypothesis

24. D) I keep four separate sets of cheese in the refrigerator: -five slices that I touch once a day; -five slices that I leave untouched; -five cubes of unsliced cheese that I touch one a day; -and five cubes that I leave untouched. • Experiment

25. C) After five days, both sets of cheese that I touched are moldy. Both sets of cheese that I left alone have no mold. • Data results

26. F) My hypothesis was supported; touching is the critical factor in making cheese mold. • Conclusion

27. Identifying Independent and Dependent Variables& Writing Hypotheses • IV • variable the experimenter deliberately manipulates/changes • DV • variable that changes as a result/in response to changes in the IV • Control • experimental set-up deliberately kept constant/unchanged for comparison

28. Identify IV, DV, Control Then develop hypothesis Example: Does the amount of fertilizer affect the growth of a plant?

29. 1. Two groups of students were tested to compare their speed working with math problems. Each group was given the same problems. One group used calculators and the other group computed without calculators. Check for Understanding C.F.U.

30. #2 and #3. are on your own (independent practice)

31. 2. A study was done to find if tire treads size affects the braking distance of a car.

32. 3. An experiment was performed to determine how the amount of coffee grounds could affect the strength of coffee. The kind of coffee, coffee pot, amount and type of water, and brewing time were all the same.

33. Writing Hypotheses and Designing Experiments • Problem: Your bedroom air conditioner blows very cold at night, but only cool air during the day. • Observation: Your bedroom gets lots of direct sunlight all day long. • Hypothesis: • If the curtains are closed, then the room will be cooler during the day. Check for Understanding C.F.U.

34. Experiment • Day 1: leave curtains open, record temp (inside and out) [control] • Day 2: close curtain halfway, record temps • Day 3: close curtain all the way, record temps • Repeat 3 times for more valid results

35. #2 on your own (independent practice)