Experimental Design: Studying People Scientifically

Activity 2A: The Pellagra Story September 4, 2013

Activity 2: The Pellagra StorySeptember 4, 2013

Getting Started: Imagine that doctors are observing a new disease, and they don’t know what causes it. What are some possible causes of disease?

Introduction: Read the introduction on pg. A-8 and answer the following question using RACE: According to the passage, what is one way scientists solve a problem?

The Pellagra Story

Although scientists use many methods to solve problems, scientists in the same field frequently use similar approaches. Often these involve doing an experiment. For example, if a botanist (someone that studies plants) wanted to develop plants that resist drought, the botanist would use many plants and follow procedures common to many …

What are the common elements of all scientific problem solving methods?

2A

Challenge: Rewrite the challenge question in your own words.

Key Words: ethics, evidence, inference, observation, trade offs.

Procedure: Read page A-9. Do you understand the procedure on pg. A-9? Write one sentence that describes what you will be doing.

Results: View video (Full Screen Version) and use table (student sheet 2.1) to take notes.

Discussion and complete 2.2, “Observations and Inferences”Complete questions 1 and 2 on 2.2 “Observations and Inferences”

Analysis: Discuss Questions 1-3Complete The Pellagra Story: Dr. Goldberger and the Traditional scientific Method and answer question 4Complete questions 5 and 6.

Reflection: How do people in different careers solve problems? Scientists, plumbers, engineers, auto mechanics, nurses, teachers, and many other workers solve problems. Choose two careers that interest you. Describe the kinds of problems you think people face in these careers. Describe how you think they solve them.

Question 1

a) What was the first step in Dr. Goldberger’s research into pellagra?

b) During this first step in his research, what evidence did Dr. Goldberger find that suggested that pellagra was not caused by germs?

Question 2

a. What was Dr. Goldberger’s hypothesis about the cause of pellagra?

b. What did he do to provide evidence of the relationship between pellagra and nutrition? Be sure to explain how his research provided evidence that supported or disproved his hypothesis.

c. How could he have provided more convincing evidence of the relationship between pellagra and nutrition?

Question 3

Why didn’t people believe Dr. Goldberger’s conclusion about the cause of pellagra? Give two reasons.

Question 3 (cont.)

• In this activity, if a person finds that the drink tastes worse, the headache is gone, but there are side effects.

b. What if the side effects were serious, such as nausea and vomiting? Explain why this medicine should or should not be sold to people suffering from headache. Are there any trade-offs involved in your decision?

Question 4

• Compare the steps of the traditional scientific method to the steps Dr. Goldberger followed to investigate pellagra. How were the steps the same? How were the steps different?

Question 5

Fill in the “After Column for statements 3 and 4 only on Sheet 1.1, “Anticipation Guide: Ideas about Experimental Design.” Did your thinking change?

Question 6

To investigate his hypothesis, Dr. Goldberger had prisoners volunteer to be fed a poor diet; as a result, 7 out of 11 prisoners developed pellagra. What do you think about Dr. Goldberger’s decision to experiment on people? Support your answer with evidence and identify the trade-offs of your decision.

What if…

Should the prisoners – who had comitted crimes ranging from embezzlement to murder - have been released from prison if they participated in Dr. Goldberger’s study? Why or why not? What are the trade-offs involved in this decision?

• Use the table (student sheet 2.1) to take notes and discuss with your partner.

The Concepts of Evidence and inference.

• In the video, one of the presenters said, “the fact that orphans provided with fresh vegetables, meat, and milk either recovered from pellagra or did not get it was not scientific evidence.

Why do you think the presenter made this comment? Do you agree with the presenter? Why or why not?