1. The Scientific Method
TSW identify the steps of the scientific method & differentiate between IV & DV

2. Steps of the Scientific Method
Problem/Question
Observation/Research
Formulate a hypothesis
Experiment
Collect and analyze results
Conclusion
Communicate the results

3. 1. Problem/Question What do you want to know?
Must be able to solve through experimentation

4. 2. Observation/Research
Investigate your topic of research

5. 3. Formulate a Hypothesis
Predict a possible answer to the problem or question
Example: If soil temperatures rise, then plant growth will increase.

6. 4. Experiment Develop and follow a step-by-step procedure
Be specific so that other scientists can duplicate your experiment

7. 4a. Independent Variable
The manipulated variable
What “I” choose to change
Example: If soil temperatures rise, then plant growth will increase.

8. 4b. Dependent Variable The responding variable
What changes in response to changes made to the IV
Example: If soil temperatures rise, then plant growth will increase.

9. 4c. Control Group that receives none of the IV
May be a “no treatment” group or an “experimenter selected” group
Serves as a standard of comparison for other trials

10. 4d. Constants
All factors that an experimenter chooses to keep the same

11. 5. Collect & Analyze Results
Confirm results by retesting
Include tables, graphs, diagrams, photos, etc.

12. 6. Conclusion Decide whether to accept or reject your hypothesis
Make recommendations for further study or improvements to your experiment

13. 7. Communicate the Results
Discuss your results with an audience

14. Think you can remember all 7 steps?

15. Let’s apply our knowledge of the Scientific Method to a realistic example.
What’s the first step?

16. 1. Problem/Question
John watches his grandmother bake bread. He asks her what makes the bread rise. She explains that yeast in the dough releases a gas as it feeds on sugar.
What might John’s question be?

17. 1. Problem/Question
Does the amount of sugar used in the recipe have an effect on the size of the bread loaf?

18. 2. Observation/Research
John researches the areas of baking and fermentation and tries to come up with a way to test his question.
What does he need to do next?

19. 3. Formulate a Hypothesis
If more sugar is added to the dough, then the bread will rise higher.
Notice that there is a direct relationship between the IV and the DV.

20. 4. Experiment
John’s teacher helps him come up with a step-by-step procedure and a list of needed materials. She discussed with him how to determine the IV, DV, control and constants.

21. 4a. Independent Variable
What did John choose to change in this experiment?
IV: The amount of sugar added to the dough
Example: 25g., 50g., 100g., 250g.

22. 4b. Dependent Variable
What responded to the changes in the amount of sugar?
DV: The height of the rising bread
What’s next?

23. 4c. Control
Since John’s grandmother always used 50g. of sugar in her recipe, John decided to use that amount in his control group.
This will be his standard of comparison.

24. 4d. Constants Can you think of any constants for John’s experiment?
Example: Other ingredients in the recipe, oven used, rise time, type of pan used, oven temperature, age of the yeast, etc…

25. Collect & Analyze Results Size of Baked Bread (cm³)
Amount of Sugar (g.) 1 2 3
Average size (cm³)
25 g.
768
744
761
758
50 g.
1296
1188
1260
100 g.
672
576
588
612
250 g.
432
504
360

26. 6. Conclusion
What do you think? Should John accept or reject his hypothesis?

27. 7. Communicate the Results
John tells his grandmother about his results and prepares to present his findings to his classmates.