Scientific Method


[Read the story and answer the questions. Also copy the definitions given. Do not copy material enclosed in brackets.]

Steps of the Scientific Method:
•State the problem
•Gathering Information
•Form a hypothesis
•Test the Hypothesis with an Experiment
•Collecting and Analyzing the Data
•Drawing Conclusion

[Apply each step in the scientific method to the story below.]

State the problem:
[A pet owner had his four cats boarded while he travels. The cats seemed healthy when they arrived, but a technician notices that two of the cats start scratching and chewing at their skin. After three days, these same two cats have bare patches of skin with red sores.]
1. What is the problem?

Gathering Information:
[The technician knows that cat's sometimes change their behavior when moved to a new place, so she watches all four cats for two days. Other than the scratching and chewing by the cats with sores, the behavior of all four cats seems the same. The technician called the owner and found out that he fed the cats the same food as she did.
While observing the cats, the technician also noticed that the cats scratched most after using the litter box. She called the owner and asked what brand of litter he put in the cat's litter box. The owner used a different brand than she did, so she compared the ingredients of the two kinds of litter. The difference was that the owners litter was deodorant free, while the brand she used had a deodorant.]
2. What three pieces of information were gathered?

Form a hypothesis:
[Based on the information gathered, the next thing the technician does is form a hypothesis.]
•A hypothesis is an explanation that can be tested. (Copy this definition)
3. What hypothesis should the technician form?

Test the Hypothesis with an Experiment:
[The technician gets the cats owner's permission to test her hypothesis.]
4. How you would test the hypothesis?

Controls
•A control is the standard to which the outcome of a test is compared. (Copy this definition)
5. What “control” could you include in this testing of the hypothesis?

Variables
•A variable is something in an experiment that can change. (Copy this definition)
6. What is the variable in this test?

Collecting and Analyzing the Data:
[The technician observes the cats for one week. During this time she collects data.]
7. What data should be collected in this test?

Drawing Conclusions:
[The data shows that the control cat scratches and chews more often than the experimental cat does. The sores on the skin of the experimental cat begin to heal, but those on the control cat do not.]
8. What conclusion can be drawn from this data?

[Further testing to be more sure that the conclusion is correct:]

9. How could the control cat be used to support the conclusion?

10. How could the experimental cat be used to verify the conclusion?

11. Would both of these latter tests be ethical on someone's pet?

(Adapted from a story in Glencoe's Life Science textbook.)