1. Scientific Method
How is Science Made?

2. Observation 1. Observation: See that there is a problem.
-Most students recognized that there was a big stain on my shirt
-Make sure there is only one problem being studied!!!

3. Research the Problem Look up everything you can on your topic
Visit your library or go on the internet
Conduct personal interviews
Search for articles (magazines, journals, books, newspapers) that have been written about the topic you are interested in

4. Hypothesis 2. Hypothesis: an educated guess
-Possible answers to questions generated by your observations
-Typically written as an “if and then” statement
-“If’ =hypothesis
-“Then” = results received after the controlled experiment.

5. Example of “if” “then” hypothesis
"If a plant receives fertilizer, then it will grow to be bigger than a plant that does not receive fertilizer.”

6. **It involves a prediction, which explains the problem.
Ex. of a prediction: The spot on Mrs. Gates shirt is oil
Then use that prediction to make a hypothesis.
Ex: If the spot on Mrs. Gates shirt is oil, then the spot should look and smell like oil.

7. Experiment 3. Experiment: Develop and conduct a controlled experiment.
-Test one variable at a time

8. Ex: compare the smell on my shirt to regular oil
Ex: compare the smell on my shirt to regular oil. Dump oil on an identical shirt and see if the spots look similar. Also put ink, paint, and dirt on the same shirt and compare those spots to the “mystery spot.”

9. An experiment must have a controlled variable and a manipulated variable
Control: Serves as a standard for comparison. The control must remain the same throughout the experiment. Ex: the shirt that I am wearing will be the control.
Variable: A variable that is being changed in the experiment. Ex: the spots of ink, paint, dirt, and oil are the variables in this experiment.

10. Qualitative vs. Quantitative Data
-Data that uses numbers
-(Height- John is 6’2” Weight- 195 lbs )
Qualitative
-Descriptive, no numbers
-Involves characteristics that
can’t be measured
-Ex. Study of how
gorillas behave

11. Components of a controlled experiment
A. Control setup
Setup in which all conditions are kept the same
B. Experimental setup
Setup in which all conditions are kept the same except for the one being tested
C. Independent variable
The condition (variable) being changed by you
D. Dependent variable
The condition (variable) being observed or measured in the experiment
Problem: Does the level of iron in a mouse’s diet affect the number of its red blood cells?
A. Control setup
Normal mouse feed (what is normally fed to the mouse everyday)
Mouse fed different levels of iron in the feed
Different amounts of iron added/subtracted from the feed
Number of red blood cells

12. Record Results
4. Record results: Scientists must keep accurate records of data and observations.
Ex: write down the differences and similarities of the different spots.

13. Analyze Results 5. Analyze results: Make sense of the data.
Ex: which spots smelled and looked more similar to the “mystery spot.”

14. Conclusion
6. Make a conclusion: Was your hypothesis supported or proven false. You cannot “prove” a hypothesis after just one experiment. It is not correct to say that the hypothesis was proven correct.
It is correct to say that the data supports my hypothesis.

15. Ex: the data supported our hypothesis that the spot on Mrs
Ex: the data supported our hypothesis that the spot on Mrs. Gates shirt was oil.

16. Scientific Method Flowchart
Observation
Hypothesis
Experiment
Record Results
Analyze Results
Conclusion

17. Redi’s Experiment on Spontaneous generation
Spontaneous generation: About 400 years ago, scientists believed that life arose from non-living matter. Ex: the spot of oil on my shirt will spontaneously turn into a bird!!!
People once thought that meat magically transforms into flies.
Francesco Redi (1668) designed a controlled experiment to try and prove this idea false.
Needham and Spallanzani’s experiments
Needham was not convinced that spontaneous generation did not exist!!!

18. Redi’s Experiment on Spontaneous Generation
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time
Several
days pass
Manipulated Variables:
gauze covering that
keeps flies away from
meat
Responding Variable:
whether maggots
appear
Maggots appear
No maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

19. Spallanzani’s Experiment
Flask is
open.
Gravy is teeming
with microorganisms.
Gravy is boiled.
Flask is
sealed.
Gravy is free of
microorganisms.
Gravy is boiled.

20. Observation vs. Inference
-Interpretation using one or more of the senses.
Ex: That object is big, green, soft, and heavy
Inference:
-Is an interpretation based on ones prior knowledge and/or experience.
Ex: The sun makes that tree grow tall .

21. Observation or Inference?
Statement Observation Inference
Object A is round and orange. X
Object A is a basketball. X
Object C is round and black and white. X
Object C is larger than Object B. X
Object B is smooth. X
Object B is a table-tennis ball. X
Each object is used in a different sport. X