The Salmonella experiment is an example of a controlled experiment (C). It manipulates the independent variable (gravity/weightlessness) and controls other variables through the use of a control group (mice injected on Earth).

1. Science or Not?

2. “What the research says ....
MitoQ is scientifically proven to
enhance and rejuvenate skin,
reducing the appearance of fine
lines and wrinkles, scars, brown
spots and skin discoloration, as well
as reducing the thinning of the skin
that occurs with aging.”
“MitoQ’s patented technology
delivers powerful antioxidant
support to your mitochondria,
the power source of your
skin’s cells.”
https://www.mitoq.com/skincare

3. 5 Scientifically Proven Ways
to Grow a Better Beard
Follow these steps to grow a better
beard:
1. Exercise
2. Reduce your stress
3. Rest
4. Diet
5. Supplements

4. Do you accept this “scientifically proven” claim?
● Scientists start with hypotheses, not conclusions
● Restate the claim as a hypothesis
○ Hypothesis: A causal explanation of why something happens

5. Experimental Design
● On a note card, design a scientific experiment that would test your hypothesis
● Be ready to share your hypothesis and experiment with the class and turn in
your note card
● Make sure you….
○ Can identify your independent and dependent variables
○ Are using proper control group(s)
○ Think about what things you want standardized
○ Consider sample size

6. Another Issue...
● Faculty are concerned about student performance and are always looking for
factors that may affect students’ overall grades
● What factors could we examine?

8. Questions to Consider
● How many groups of students would you have?
● How would you decide who should be in the control group and the
experimental group?
● Is your experimental design ethical?

9. Observational (Correlational) Experiments
● When manipulating subjects would be unethical or impossible
● When a naturalistic study is desired, e.g. animal behavior in the wild

10. Does attendance affect performance?
● Using some type of graphing software, graph the data provided
● Draw a conclusion from the data
● Print your graph and conclusion

11. What do these data indicate?

12. What do these data indicate?
Activity: Write a figure caption that describes the data in this graph.

13. Conclusions:
● Attendance appears to be a predictor of grade!
● There are trends in the data that can be detected by proper analysis
● There is an “error component” in the data (i.e. the data are often scattered
around the mean or trend line)

14. A hypothesis is best described as:
A. An educated guess
B. a causal explanation for a set of observations
C. a prediction of experimental results
D. a scientific idea

15. Predictions are:
A. Another form of a hypothesis
B. Expected outcomes of experiments
C. Independent variables
D. Explanations of future events.

16. A theory is best described as:
A. an idea or hunch
B. unproven explanations
C. better than hypotheses, but not as good as laws
D. broad, well supported explanations of facts

17. Timmy has noticed that his dog Lassie is scratching. He
thinks Lassie might have fleas. His suspicion is a(n):
A. experiment
B. prediction
C. hypothesis
D. theory

18. The Krebs Cycle, a well-studied and well-supported
explanation for part of the way glucose is used by organisms,
would best be considered a(n):
A. fact
B. observation
C. idea
D. law
E. theory

19. Scientists recently tested the effects of weightlessness on the
toxicity of Salmonella bacteria by injecting mice with
Salmonella while in orbit around the earth on the International
Space Station, and counting the number of dead mice at the
end of the trial. Which of the following would serve as the
control in the experiment?
A. A sample of E. coli bacteria sent into space
B. A sample of Salmonella sent into space and injected into rats
C. A sample of Salmonella injected into mice on earth
D. A sample of Salmonella sent into space but not injected into
anything
E. A sample of E. coli bacteria injected into mice on earth.

20. In the experiment on Salmonella, gravity is the:
a) independent variable and should be graphed on the x-axis
b) dependent variable and should be graphed on the x-axis
c) independent variable and should be graphed on the y- axis
d) dependent variable and should be graphed on the y-axis
e) control variable and should be graphed on the z-axis

21. The Salmonella experiment is an example of a(n)
__.
A. observational experiment
B. double-blind experiment
C. controlled experiment
D. placebo experiment
E. cellular experiment