1. The Scientific Method

2. What is the Scientific Method?
A logical problem solving process to investigate a scientific problem.
No one completely correct set of steps
Depends on problem/research

3. Steps in the Scientific Method
State the Problem
Research
Form a Hypothesis
Design an Experiment
Test the Hypothesis
Organize the Data
Draw Conclusions

4. State the Problem Observe a discrepancy
Doesn’t belong
Unexpected
Example: My snow peas aren’t producing many pods.

5. State the Problem State the problem as a question
Can’t be answered by Yes or No.
Use: How, When, What, Where, and Why
(Why can be problematic)
Specific but not cumbersome
Must be testable
Two variables
Independent
Dependent
Example: Will fertilizer increase snow pea pod production?
Example: What effect does fertilizer have on snow peas?

6. Writing a Statement of the Problem
What is the effect of chemicals?
What is the effect of chemicals on health?
What is the effect of vitamins on health?
What is the effect of Vitamin C on health?
What is the effect of Vitamin C on human health?
What is the effect of Vitamin C on the occurrence of the common cold in humans?

7. Research
Find prior information about your problem (background information)
Make initial observations
Use your five senses
Apply previous knowledge
Make inferences
Gather factual information
Use books, journals, computer, etc

8. Form a Hypothesis Predict what will happen
Best guess or possible explanation
Determines a possible solution
Write as “If…then” or ‘If…then…than’ statement (If = cause; Then = effect)
Must be testable
Includes two variables
Independent
Dependent

9. Independent Variables
The variable that is different or being tested.
Also called the Manipulated Variable
‘Cause’ part of Cause and Effect
Graphed on the X axis
Example: IF fertilizer is used, THEN the plants will produce more pea pods THAN the plants without the fertilizer.

10. Dependent Variables
The variable that responds to changes in the Independent Variable
Also called the Responding Variable
‘Effect’ part of Cause and Effect
Graphed on the Y axis
Example: IF fertilizer is used, THEN the plants will produce more pea pods THAN the plants without the fertilizer.

11. Independent Variable # pea pods Dependent Variable Treatment
Fig. 1. Pea Plant pod production on pea plants with and without fertilizer.

12. Form a Hypothesis - Examples
Problem 1: What effect does fertilizer have on snow peas?
Hypothesis 1: IF fertilizer is used, THEN the plants will produce more pea pods THAN the plants without the fertilizer.
Problem 2: What is the effect of Vitamin C on the occurrence of the common cold in humans?
Hypothesis 2: IF 500mg of Vitamin C is given daily, THEN it will prevent the common cold in humans.

13. Design an Experiment Establish at least two test groups
Experimental-the independent variable is applied to this group
Control-comparison or normal group; no independent variable applied
Provide a list of materials
Develop a procedure
Explains what is to be done and when

14. Test Groups Pea Plants Control group: Test or Experimental Group:
Vitamin C
Water
Fertilizer
Placebo (no vit. C)
500 mg Vitamin C daily

15. Controlled Variables (Constants)
Factors that remain the same throughout the experiment
Are the same for both the control and experimental groups.
Don’t change
Includes everything except the independent variable
Pea Plants: water, light, temperature, etc
Vitamin C: age, sex, weight, diet, etc

16. Test the Hypothesis
Make sure all variables are controlled except for your independent variable
Follow the procedure
Record your observations
Record any mistakes, accidents, weather, etc. that might affect the results
The experiment provides evidence for or against the hypothesis

17. Collect Data Use logs, journals, tables and graphs
Record all observations
Include things you don’t think are important
Qualitative Data
Quantitative Data
Include time, units, duration, # trials or sets, etc.
Be specific!

18. Organize the Data Daily Log Tables Graphs Repetitive data
Continuous data
Discontinuous data

19. Daily Log The Effect of Fertilizer on Pea Production – Daily Log Day
Date
Time
Temp
Comments and Observations 1
5/14
9 am 99
Planted seed and placed in direct sunlight for 6 hours
2-10 23
Avg. 98
Sprouts are showing in both groups 11 24 96
No discernable difference between groups 12 25 95
Same 13 26 91
Same growth rate; approx. 6 in tall. 14 27
Plants are growing full sized leaves

20. Tables Repetitive data Like elements read down Title goes at the TOP!
Compact and easy to read
Title goes at the TOP!
Table 1: How to correctly set up a table.
Heading
Related data

21. Tables Fertilizer Water Group 1 18 10 Group 2 21 8 Group 3 15 11
Title
Table 1: The number of pea pods produced for each treatment per group of pea plants.
Fertilizer
Water
Group 1 18 10
Group 2 21 8
Group 3 15 11
Group 4 12
Total 66 39
Average
16.5
9.75

22. Graphs or Figures Visual representation Shows relationships
Title at the BOTTOM!
Includes:
Pictures (Figures)
Bar graphs
Discontinuous data
Line graphs
Continuous data
Pie charts

23. Discontinuous Data Sharp, dramatic differences
Either – Or, no blending
Examples:
color
Grade
sex

24. Graphs or Figures Discontinuous Data
# pea pods
Dependent Variable
Treatment
Independent Variable
Title
Fig. 1. Pea Plant pod production on pea plants with and without fertilizer.

25. Continuous Data Regular, gradual changes Shows linear relationships
Examples:
Distance
Temperature
Time
Weight
Height
Age

26. Graphs or Figures- Continuous Data
Revolutions
Dependent Variable
Time (Min.)
Independent Variable
Title
Fig. 1. Revolutions of an exercise wheel powered by a hamster over time.

27. Draw Conclusions Analyze your data and summarize your findings.
Is a judgment based on the results
Can agree, disagree, or reveal nothing about the hypothesis
State potential flaws

28. Publish and/or Repeat Publish in a peer-reviewed journal
Allows others to critique and test
Important research:
Design different experiments to test the hypothesis or generate additional hypotheses.