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Activity 2: The Pellagra Story Evidence, observation, inference, tradeoff, ethics Challenge : What are the common methods of scientific problem solving?

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Presentation on theme: "Activity 2: The Pellagra Story Evidence, observation, inference, tradeoff, ethics Challenge : What are the common methods of scientific problem solving?"— Presentation transcript:

1 Activity 2: The Pellagra Story Evidence, observation, inference, tradeoff, ethics Challenge : What are the common methods of scientific problem solving? Introduction: Vocabulary: Procedure : White space How do you think doctors determine the cause of a disease? Materials: Data: Analysis: Video and notes on video 1 Student Sheet 2.3, 1 Student Sheet 2.2, AQ 1, AQ 2b, 4, 5, 6

2 odys08_vid_pellagra_350.mov Imagine that doctors are observing a new disease, and they dont know what causes it. What are some possible causes of diseases? What kinds of things would scientists do to learn more about a disease and its cause or causes? Read the Analysis questions Watch the Video clip on pellagra one time, just listening carefully. Watch the Video clip on pellagra again, taking notes on handout student sheet

3 Analysis Questions 1.a. What was the first step in Dr. Goldbergers research into pellagra? Explain why this step was important in developing his hypothesis. b. During this first step in his research, what evidence did Dr. Goldberger find that suggested that pellagra was not caused by germs? 2. 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.

4 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? 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? 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. Goldbergers decision to experiment on people? Support your answer with evidence and identify the trade-offs of your decision. Hint: To write a complete answer, first state your opinion. Provide two or more pieces of evidence that support your opinion. Then consider all sides of the issue and identify the trade-offs of your decision. Analysis Questions

5 What was the problem of pellagra? In 1914, pellagra was a common disease in the United States. It caused rashes, insanity and death. What did people think caused pellagra? 1. Eating corn 2. An insect 3. Bacteria/germs 4. Lack of nutrition/poor diet What evidence did Dr. Goldberger observe or collect about pellagra? Pellagra was common in the South, particularly in poor areas and institutions (such as mental hospitals, orphanages, and prisons). Many people in the South ate a poor diet, consisting of cornbread, fatback (pork), and syrup. Staff at institutions (such as mental hospitals, orphanages, and prisons) did not have pellagra. Orphans provided with fresh vegetables, meat, and milk either recovered from pellagra or did not get it. Some prisoners fed a poor diet developed pellagra. When provided a better diet, they recovered. What did Dr. Goldberger conclude about the cause of pellagra? Dr. Goldberger concluded that pellagra was caused by a nutritional deficiency (poor diet).

6 Take out your Vocabulary Log Observation: Any description or measurement gathered by the senses Inference: A conclusion, or the process of developing a conclusion based on evidence.

7 In the video clip, one of the presenters comments that 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? 3

8 D.A.R.T.

9 Key to Student Sheet 2.2, Observations and Inferences Identify each of the following statements as either an observation or an inference that was made about pellagra. Observation Inference ___ X* Corn causes pellagra. X ___ Only children in the orphanage developed pellagra. The staff did not. X ___ Changing the orphans diet cured those who had pellagra. X ___ Only people who lived in the South got pellagra. ___ X Pellagra is not an infectious disease. X ___ Pellagra causes skin rashes and, eventually, insanity. ___ X* People get pellagra because they are poor. ___ X Pellagra is caused by diet. X ___ Orphans and prisoners who ate a balanced diet did not develop pellagra. ___ X* The Southern way of life caused pellagra. 1.Look at the statements that you marked as inferences. Based on the evidence that Dr. Goldberger found, put a star next to each inference that is faulty. 2.Choose one of the inferences that you put a star next to, and explain how that inference could have been made based on observations.

10 The Pellagra Story: Dr. Goldberger and the Traditional Scientific Method Steps of the traditional scientific methodSame or different?Steps taken by Dr. Goldberger State the Problem or QuestionSame Dr. Goldberger was presented with the problem "What causes Pellagra?" when asked to investigate. Propose an explanation (hypothesis)Same Dr. Goldberger hypothesized that an inadequate diet caused pellagra. Dr. Goldberger fed orphans a balanced diet and observed it's effect on Pellagra Same Collect Evidence (experiment) Analyze data SameDr. Goldberger recorded and analyzed data about orphans Draw conclusions, and if necessary, revise and repeat Different Dr. Goldberger did not draw a final conclusion after his investigation with the orphans. He obtained more evidence by conduction an experiment with prisoners.

11 Analysis Question 1a 1. a. What was the first step in Dr. Goldbergers research into pellagra? Explain why this step was important in developing his hypothesis. The first thing that Dr. Goldberger did was to visit sites where pellagra was prevalent. He focused on the southern United States and visited institutions such as orphanages and prisons. He conducted this background investigation before forming any hypothesis for the cause of pellagra. This was an important step in developing his ideas. It was during this initial period that Dr. Goldberger observed common factors (such as poverty and diet) linked to pellagra and therefore hypothesized that pellagra may be a nutritional deficiency (poor diet). These are often overlooked elements of scientific study and are usually essential to the development of strong hypotheses.

12 Analysis Question 1b During this first step in his research, what evidence did Dr. Goldberger find that suggested that pellagra was not caused by germs? Dr. Goldbergers observations about the prevalence of pellagra among poor and institutionalized people provided some evidence that pellagra did not occur randomly. He pointed out that staff at institutions where pellagra was common did not have it, while many of the patients did. This provided some evidence that pellagra was not an infectious disease, since victims did not transmit it to the staff.

13 Scoring Guide LEVELDESCRIPTION Level 4 Student accomplishes Level 3 and goes beyond in some Above and beyondsignificant way, such as: questioning or justifying the source, validity, and/or quantity of evidence. Level 3Student identifies key evidence with the appropriate facts, data and Complete and correctobservations. Level 2Student includes some, but not all, relevant evidence Almost thereBUT student omits key evidence OR provides an insufficient number of facts, data, and observations. Level 1 Student states opinion as facts On your way OR student uses incorrect or irrelevant evidence. Level 0Students response is missing, illegible, or irrelevant. XStudent had no opportunity to respond.

14 Writing Frame – Recognizing Evidence I am investigating the following question: _____________________________________ ________________________________________________________________________ I have found the following facts, data, and observations that provide evidence about this question: 1. __________________________________________________________________ _____________________________________________________________________ 2.__________________________________________________________________ _____________________________________________________________________ 3.__________________________________________________________________ _____________________________________________________________________

15 Analysis Question 2b 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. He observed that the orphans with pellagra who were fed a complete diet got better. He observed that when orphans who did not have pellagra and were fed a complete diet they did not get it. He did an experiment in which he fed Prisoners a poor diet; as a result, 7 prisoners developed pellagra. He did another experiment in which then fed those patients a better diet and they got better.. He observed that people who worked in institutions did not get pellagra but their patients did.

16 Analysis 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? Use Student Sheet 2.3 to help you.

17 Analysis 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? Explain why or why not.

18 Analysis 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. Goldbergers decision to experiment on people? Support your answer with evidence and identify the trade-offs of your decision. Hint: To write a complete answer, first state your opinion. Provide two or more pieces of evidence that support your opinion. Then consider all sides of the issue and identify the trade-offs of your decision.


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