1. Scientific Method

2. Science is the use of evidence to develop testable explanations and predictions of natural phenomena. The scientific method is a systematic approach used in scientific study.

3. Scientific Method Steps in the scientific method include: 1.observation: the act of gathering information 2.hypothesis: a testable explanation or prediction 3.experiment: set of controlled observations that test the hypothesis. 4.conclusion: judgment on the information obtained

4. Scientific Method Observation Hypothesis Experiment Conclusion

5. A. Observations Observations can be quantitative or qualitative A qualitative observation does not include a numerical value. A quantitative observation includes a numerical value.

6. Measurement A measurement consists of two things: a quantitative observation (magnitude) and a unit Examples 0.7 mm Magnitude (quantity) unit 120 lbs Magnitude (quantity) unit

7. The paragraph below was a summary of a chemistry experiment done a few years ago. Write down 5 qualitative observations and 5 quantitative observations: Monica measured 2.20 grams of copper chloride dihydrate. The copper chloride dihydrate was bright green and looked like the pop rocks candy. Once the copper chloride dihydrate was dissolved in 25 mL of water, it turned into an aqua blue solution. The temperature of the solution was 22°C. Next, 0.45 g of aluminum foil was loosely balled up and added to the solution. Bubbles immediately formed and the aluminum started to turn dark red. Condensation formed along the sides of the beaker, and the overall solution turned dark green, then grey. The final temperature of the solution was 42°C.

8. Scientific Method Observation Hypothesis Experiment Conclusion

9. B. Hypothesis Hypotheses are tentative and testable statements that are capable of being supported or not supported by observational evidence. Related to the data provided Hypotheses that involve testing the emotions of animals are not valid.

10. Clouds are more beautiful on winter days than on summer days. This statement is a poor hypothesis because it is not — A a question B testable C observable D a comparison

11. Students placed equal amounts of bread mold on 12 identical agar plates containing the same amounts and types of nutrients. Four plates were kept at 0°C, four were kept at 45°C, and four were kept at 22°C (room temperature). The plates were examined after five days. Which of the following was probably the hypothesis for this experiment? F The growth of bread mold increases as temperature increases. G The type of nutrient causes bread mold to grow faster at higher temperatures. H The size of the plates determines the temperature of bread mold. J The temperature of bread mold is determined by the mold’s growth.

14. Hypotheses vs Theories Scientific theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers. Unlike hypotheses, scientific theories are well-established and highly- reliable explanations, but may be subject to change as new areas of science and new technologies are developed.

15. Theories you may have heard of: Theory of evolution Big Bang theory

16. Theories vs Laws A theory is an explanation that has been supported by many, many experiments. Note, theories are constantly evolving and grow stronger as we learn more. Theories provide an explanation for a wide range of observations. A good theory can be used to make predictions.

17. Theories vs Laws A (scientific) law is an observation only of natural phenomena. It offers no explanation as to why it happens. –Ex: Gravity is a law. We have no concrete explanation for it. Plate tectonics is a theory. It explains and predicts volcanoes and earthquakes

18. Scientific Method Observation Hypothesis Experiment Conclusion

19. Important parts of an experiment include: 1 variable is being tested (independent variable) Dependent variable is being measured Many controlled variables 1 experimental control (for comparison) Be precise by using precise equipment & the same equipment each time Do multiple trials!!! Average your results from the multiple trials Make a note of any outlying data or experimental errors

20. In experiments, a benefit of larger sample sizes would be more — A variables B representative data C time per group D control groups

21. An engineer has created a new engine for race cars. It is necessary to know which fuel mixture will allow the engine to run at its peak performance. Which experimental design is best for this investigation? F Use one fuel mixture on the engine and measure its performance G Use one fuel mixture on many types of engines and measure their performance HUse various fuel mixtures on the engine and measure its performance J Use various fuel mixtures on many types of engines and measure their performance

22. Variables  Experiments will consist of variables (a quantity or condition that can have more than one value.)

23. Experimental Control  Experimental Control: An experimental control is something that is not manipulated and is being used for comparison.)

24. Sample Problem

25. 3 Types of Variables Independent variable: the one that you deliberately change (manipulative) Dependent variable: the one that you measure (responding) Controlled variable: a factor that is not allowed to change during the experiment

26. Variables Independent Dependent Control manipulative Being Changed Being measured Depends on the Ind. Var. Doesn’t Change Several per experiment On X axis On Y axis

27. Practice Students placed equal amounts of bread mold on 12 identical agar plates containing the same amounts and types of nutrients. Four plates were kept at 0°C, four were kept at 45°C, and four were kept at 22°C (room temperature). Determine the following: Independent Variable = Dependent Variable = Controlled Variables = Experimental Control = Temperature of bread mold Amount of bread mold Write a hypothesis The growth of bread mold increases as temperature increases. Agar plates, amount of nutrients, type of nutrients Sample at room temperature

28. Recording your data on a data table Include a title Include units Independent variables can be filled in before the experiment Measured/Dependent variables are filled in as you complete the experiment title units Independent Var.Dependent Var.

29. Scientific Method Observation Hypothesis Experiment Conclusion

30. D. Conclusions A summary of the experiment that reflects the data you collected Graph your data & determine any trends “DRY MIX” = dependent or responding variable on the Y-axis & manipulative or independent variable on the X-axis

31. DRY MIX Dependent or Responding on Y Manipulative or Independent on X Y X Independent Variable Dependent Variable

32. Determine the Dependent & Independent Variables Independent Variable Dependent Variable

33. Experiment Amount of Studying vs Test Grades What is my independent variable? What is my dependent variable? What are my controlled variables? How would I label my axis in a graph?

34. Studying Vs Test Grades Independent Variable Dependent Variable Test Grades Amount of Studying In this experiment, what needs to stay the same? (what are some controlled variables)

35. D. Conclusions o Two quantities are directly proportional if dividing one by the other gives a constant value. If graphed, it would produce a straight line EX:mass and volume in density relationship D= m/v Is your data directly proportional or inversely proportional?

36. D. Conclusions o Two quantities are inversely proportional to each other if their product is constant. A graph of an inverse proportion would produce a curve. EX: mass and acceleration in Newton’s second law F=ma Is your data directly proportional or inversely proportional?

37. Conclusion vs Inference A conclusion is simply a statement based only on experimental facts A inference which makes a statement beyond the facts.

38. Conclusion vs Inference Ex: You heat a liquid substance and a gas is produced. Conclusion: When liquid A was heated, a gas was produced. Inferences: A gas was produced because liquid A was heated.

40. Conclusion