1. ISCI 2002 Physical Science for Teachers
Scientific Method
ISCI 2002
Physical Science for Teachers

2. What is the Scientific Method?
Series of Steps?
Scientist use different approaches; different types of evaluations
Steps used by most
Observation of nature
Explanation of what is observed
Explanations used to make predictions
Test predictions
Modify explanation
No set order or routine

3. Formulation of a Hypothesis
An “educated guess” based on previous research or experimentation.
Explanation (experiment derived explanation)
“Tentative”
Must be tested. May be accepted or rejected
Universal hypothesis statement
As the independent variable (increases, decreases) the dependent variable will (increase, decrease)
Variables
Independent vs dependent

4. Testing the Hypothesis
Simple
Hypothesis: “birds build nests in tree cavities”
Observe and record
More complex
devise an experiment
Production of a ‘song’ by a bird
Many variables involved (nervous and muscular systems; environmental factors)
Try and understand the (of the previous variables) roles of the factors in the production of a song.

5. Control vs. Experimental Tests
Controlled experimental set-up
Compares two situations that have identical factors except for one that differs
Controlled group
All factors are the same
Experimental set-up
One factor or variable is changed and observed

6. Bird Song Example
Simple questions are formulated (deals with each variable or factor involved)
Muscles; nervous system; hormones; climate; etc.
How do male sex hormones stimulate male birds to sing?
Experimental group: male bird testes removed
Controlled group: testes remain in tact
Look to see if there is a relationship between the groups or not (did removing the testes affect the birds ability to sing?)

7. Collecting Data Displayed in table, charts, etc. Time
Growth in Height (cm)
Day 1
2.5 cm
Day 2
4.5 cm
Day 3
6.5 cm
Day 4
8.5 cm
Day 5
10. 5 cm

8. Analyzing Data Analyzing
Charts
Graphs
Statistics
Was there a relationship between the variables?
Direct
Indirect
None observed
Quantitative and Qualitative

9. Graphing Data
Time (days)

10. Graphical Analysis Rate or Slope = rise/run Rate = Y2-Y1/X2-X1
Calculating the rate or ‘slope’
Rate or Slope = rise/run
Rate = Y2-Y1/X2-X1

11. Graphing Data
Time (days)

12. Conclusion(s)
Based on the analysis of the data was the hypothesis accepted or rejected?
Recommendations for retesting? Modifications?