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

3. Problem/Question From Observation/Research Formulate a Hypothesis Experiment Collect and Analyze Results Draw a Conclusion and Communicate the Results

4. Let’s put our knowledge of the Scientific Method to a realistic example that includes some of the terms you’ll be needing to use and understand.

5. Problem/Question John watches his grandmother bake bread. He ask his grandmother what makes the bread rise. She explains that yeast releases a gas as it feeds on sugar.

6. Problem/Question John wonders if the amount of sugar used in the recipe will affect the size of the bread loaf?

7. Caution! Be careful how you use effect and affect. Effect is usually a noun and affect, a verb. “ The effect of sugar amounts on the rising of bread.” “How does sugar affect the rising of bread?”

8. Observation/Research John researches the areas of baking and fermentation and tries to come up with a way to test his question. He keeps all of his information on this topic in a journal.

9. Formulate a Hypothesis After talking with his teacher and conducting further research, he comes up with a hypothesis. “If more sugar is added, then the bread will rise higher.”

10. 4 Types of Variables Independent Variable Dependent Variable Control Group Constants

11. Do you know the difference between the independent and dependent variables?

12. Independent Variable The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter. The Independent Variable is the 1 and only thing that will be purposely changed in the experiment.

13. Independent Variable The independent variable in John’s experiment will be the amount of sugar. He is deliberately designing his experiment to test different amounts of sugar. John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment.

14. Dependent Variable The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable. The dependent variable is what is affected.

15. Dependent Variable John’s independent variable was the amount of sugar. John believes that more sugar will make his bread rise higher. In this case the dependent variable would be the size of the loaf of bread.

16. Experiment His teacher helps him come up with a procedure and list of needed materials. She discusses with John how to determine the control group.

17. Control Group In a scientific experiment, the control is the group that serves as the standard of comparison. The control group may be a “no treatment" or an “experimenter selected” group.

18. Control Group The control group is exposed to the same conditions as the experimental group, except for the variable being tested. All experiments should have a control group.

19. Control Group Because his grandmother always used 50g. of sugar in her recipe, John is going to use that amount in his control group.

20. Constants John’s teacher reminds him to keep all other factors the same so that any observed changes in the bread can be attributed to the variation in the amount of sugar.

21. Constants The constants in an experiment are all the factors that the experimenter attempts to keep the same.

22. Constants They might include: Other ingredients to the bread recipe, oven used, rise time, brand of ingredients, cooking time, type of pan used, air temperature and humidity where the bread was rising, oven temperature, age of the yeast…

23. Experiment John writes out his procedure for his experiment along with a materials list in his journal. He has both of these checked by his teacher where she checks for any safety concerns.

24. Trials Trials refer to replicate groups that are exposed to the same conditions in an experiment. John is going to test each sugar variable 3 times.

25. Collect and Analyze Results John comes up with a table he can use to record his data. John gets all his materials together and carries out his experiment.

26. Size of Baked Bread (LxWxH) cm 3 Amt. of Sugar (g.) 123Average Size (cm 3 ) 25768744761758 501296118812961260 10011881080 1116 250672576588612 500432504360432 Size of Bread Loaf (cm 3 ) Trials Control group

27. Collect and Analyze Results John examines his data and notices that his control worked the best in this experiment, but not significantly better than 100g. of sugar.

28. Conclusion John rejects his hypothesis, but decides to re-test using sugar amounts between 50g. and 100g.

29. Experiment Once again, John gathers his materials and carries out his experiment. Here are the results.

30. Size of Baked Bread (LxWxH) cm 3 Amt. of Sugar (g.) 123Average Size (cm 3 ) 501296144012961344 601404129614401380 701638 15601612 8014041296 1332 90108012009721084 Size of Bread Loaf (cm 3 ) Trials Control group

31. Conclusion John finds that 70g. of sugar produces the largest loaf. His hypothesis is accepted.

32. Communicate the Results John tells his grandmother about his findings and prepares to present his project in Science class.

33. Variable Example Sally has a white rose bush. It doesn’t produce many flowers. She wanders if other types of rose bushes might produce more flowers.

34. Variable Example Read the example completely and find each type of variable. Independent Variable Dependent Variable Control Group Constants

35. The Independent Variable The independent variable is what Sally is deliberately designing her experiment to change. Independent Variable The Type of Rose Bushes

36. The Dependent Variable The dependent variable is what Sally is planning to measure. Dependent Variable The Number of Flowers on each Bush

37. The Control Group The group that has not changed at all. The group that the others are being compared to. Control Group The White Rose Bush

38. The Constants All the things in her experiment that Sally kept the same. Constants Amount of time Amount of water Amount of sunlight

39. Variables in the Hypotheses If you increase the number of cigarettes you smoke, then you will increase your risk for lung cancer. Independent Variable Dependent Variable

40. Variables in the Hypotheses If you increase the amount of chum in the water, then the number of sharks in the area will increase. Independent Variable and Dependent Variable Amount of time Amount of water Amount of sunlight

41. Variables in the Hypothesis To Identify the variables in a hypothesis, the independent variable is found after the “IF” and the dependent variable is found after the “THEN”. Why? Because, the independent variable is the cause and the dependent variable is the effect.

42. Variables in Questions You will also include your variables in your question. However, the variables are not always in an obvious spot in the question.

43. Variables in Questions Does the volume of music change how active animals are? Independent Variable Dependent Variable

44. Variables in Questions Does temperature affect the rate at which plants grow? Independent Variable Dependent Variable

45. Identifying Variables in Experiments Read the experiment. Find the: –Independent Variable –Dependent Variable –Control Group

46. Recap Variables are located in all Variables are also located in all The independent variable is located after if and the dependent variable is located after then. A good hypothesis is written in the “If…then” format. Which shows a cause and effect relationship between Experiments Hypotheses Independent and Dependent Variables