Name _________________________ Date _______________
Score:
Due:
/42
Web Quest: http://www.sumanasinc.com/webcontent/animations/content/scientificmethod.html
(Link is on Cornerstone under Assignments – you can also Google “sumanasinc.com the scientific
method”).
Redi’s Experiment:
Redi and Pasteur were the first “scientists” to use scientific methods for testing whether
spontaneous generation explained the origin of life. You will study the scientific method as you
study their experiments. Fill in the information for each step of the scientific method:
1. Scientists cannot perform an experiment without first asking questions about the things they
observe around them. What was the question Redi wanted to answer?
2. Scientists make a hypothesis, a prediction that can be tested; what was Redi’s hypothesis (a
hypothesis is a statement, not a question)?
3. Scientists must design a controlled experiment that will test their hypothesis. A variable
is something in an experiment that can change. The scientist chooses one variable to change. All
other variables must be held constant. The constants are all the other variables that stay the
same throughout the experiment. For example, Redi kept all three jars in the same room so that
they had equal access to flies and were kept at the same temperature.
a. What was the variable that Redi changed (meaning what was different about the three jars)?
b. What are at least 2 other constants in his experiment?
1.
2.
4. Make a sketch of Redi’s experimental set-up (label appropriately):
5. Analyze Data: Redi collected data on the outcome of his experiments. Explain what happened in
each jar:
Jar 1
Jar 2
6. Draw Conclusions: Did Redi’s data support or oppose his hypothesis? Explain.
Jar 3
7. Did Redi’s data provide evidence for or against spontaneous generation? Explain.
Pasteur’s Experiment
1. What was the question Pasteur wanted to answer?
2. What was Pasteur’s hypothesis?
3. What was the variable that Pasteur changed?
4. List at least two variables that were held constant in his experiment:
5. Draw a sketch of Pasteur’s experiment (label appropriately):
6. Analyze Data – What were the results of the experiment?
7. Draw Conclusions – did Pasteur’s data support or oppose his hypothesis? Explain.
8. Why did Pasteur’s experiment convince most other scientists that spontaneous generation was
not supported by scientific data?
“Germ Warfare”
Directions: Answer questions about the article “Germ Warfare” (from Odyssey Magazine)
1. Why did scientists living in the early 1800’s still believe that microorganisms could spontaneously
generate?
2. Why did Felix Pouchet want to criticize Pasteur’s experiment?
3. What is a repeatable experiment and why was it necessary to have repeatable experiments in
the effort to disprove the belief in spontaneous generation?
4. What was the “flaw” in Pouchet’s experiment?
5. What technology did Pasteur invent that helped him carry out his experiment?
6. Pasteur’s results helped people understand that microorganisms such as bacteria and fungi that
can cause disease are in the air. Explain two ways that Pasteur’s experiment made life a lot safer
for people.