1. The Scientific Method

2. Scientific Method
An orderly, step by step procedure used by scientists to find the answer to a specific problem or question

3. Step 1: Define the problem or question
Why are trout in the lake are declining, but not the catfish?

4. Step 2: Obtain background information and form a HYPOTHESIS
Two chemical plants border the lake.
The Toxins R Us plant produces PCB’s.

5. The Midnight Chemicals Plant is no longer in operation.

6. HYPOTHESIS:
PCB’s are being discharged into the lake from the Toxins R Us plant, killing the trout.

7. Step 3: Design and carry out a procedure to collect and analyze data to prove or disprove the hypothesis
Monitor PCB’s in water near the Plant
Test for PCB’s in lake sediments
Test for PCB’s in different kinds of fish
Record observations in words
Record data in data tables

8. Step 4. Collect and analyze data Results:
No PCB’s Detected!

9. Revise Hypothesis:
Drums possibly leaking acid were found at abandoned Midnight Chemicals Plant. Acid is leaking into the lake and killing the trout

10. Collect and analyze more data
Collect samples of fluid in the drums
Test acidity (pH) of water coming into lake
In tanks, test the affect of acidic water on different kinds of fish
Repeat tests
Record observations in words
Record Data in a data table

11. Results: Drums contain strong acid Water entering the lake is acidic
Trout in acidic water died in tank tests
Catfish in acidic water lived in tank tests

12. Step 5: Conclusion: an interpretation of data based on repeatable experimental results
THE CONCLUSION MUST ANSWER YOUR PROBLEM QUESTION AND
EXPLAIN IT USING YOUR DATA TO JUSTIFY YOUR EXPLANATION
Trout are being killed by acid leaking into the lake from drums on the Midnight Chemicals Plant property.
Less sensitive fish, like catfish, are not adversely affected.
The End!

13. STEP 6: Communicating results is important!
Or is it?
STEP 6: Communicating results is important!
Call the EPA and get Midnight Chemicals to clean up the lake!
(or in your case, write a lab report…..)

14. Summary of Scientific Method
1. Define the problem or question
2. Form a hypothesis based on background information
Design a procedure and collect and analyze data and observations
Graph data and perform calculations
Interpret results (conclusion)
6. Communicate results