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STEPS OF THE SCIENTIFIC METHOD

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					STEPS OF THE SCIENTIFIC METHOD 1. Observation of situation that leads to a question: How does this occur, and why? What would happen if ____ was removed or added? What information do we already know about this situation? 2. Hypothesis formation (one-sentence prediction): A plausible reason why this occurs is ______. If _____ was removed or added, __________ will happen.

3. Design an experiment that produces data to collect. Data is FACTUAL information that is gathered. The experiment must be described in such detail that anyone else can read your notes and repeat the experiment exactly. The set up, equipment, and step-by-step procedure must all be this detailed. You must identify all possible variables and eliminate all but the one you want to test. The same experiment must be repeated with a CONTROLLED situation, in which no variables are tested. A control subject or group must go through all the steps of the experiment except it is not exposed the factor being tested. For example, if your hypothesis is that a particular bug will prefer sugar water to regular water, and you put the sugar water on the right side of a plate and the regular water on the left side of the plate and count the number of times the bug turns to the right, you must repeat the experiment with the same plate but with plain water on both sides of the plate. If the new bug turns more often to the right, it might be that the surface of the plate has an irregularity that the bug finds undesirable, and that it has nothing to do with the water content. 4. Analysis of the data: Usually a table is used to record the data, and the data is later plotted on a graph to show trends or relationships within the data. Do not draw conclusions at this phase.

5. Make a conclusion: Explain what the data means to you. Describe any problems with the experiment and list all the possible reasons why there might be errors in your experiment. Suggest improvements that could be made if you were to repeat this experiment in the future. Lastly, state whether your data supported your hypothesis or not, or whether it was inconclusive. Remember, experimental data can support, but DOES NOT PROVE your hypothesis.

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EXPERIMENT FROM OBSERVATION 1. OBSERVATION Have you observed that tall people have big hands and big feet? But do most tall people have big hands and small people have small feet? 2. HYPOTHESIS Tall people will have big hands and big feet, and small people will have small hands and small feet. 3. EXPERIMENTAL PROCEDURE Everyone in your lab group will record their height, shoe size, and the distance between the tip of their pinky and the tip of their thumb. All of this data will be collected on the following table:

FIRST NAME

HEIGHT

SHOE SIZE

HAND WIDTH

4. DATA ANALYSIS There will be two graphs on the board. On the first graph, plot the height on the y axis, and the shoe size on the x axis of each person in your lab group. On the second graph, plot the height on the y axis and the hand width on the x axis. Note whether there is a linear trend on the points of the graph that lead upward in shoe/hand size as height increases.

HEIGHT

HEIGHT

SHOE SIZE

HAND SPAN

5. CONCLUSION Was there a direct relationship between the two traits on the first graph? Was there a direct relationship between the two traits on the second graph? Was there anyone in the class that did not fit the trend? How do you interpret this data? Does the data support your hypothesis? Can you make generalizations from the entire human population from this experiment? Why?

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Scientific Literacy
Scientific literacy means more than being able to design and conduct experiments. You must also be able to understand how scientific research affects your life and your decisions. Consider each of these mini-cases and indicate what you think should be done in each situation. POSSIBLE FAULTS IN STUDIES A. Conclusion is not supported by data B. Biased sampling (subjects chosen for the experiment have a personal motive) C. Inadequate controls (same experiment was not repeated on a group who did not get the treatment) D. Inappropriately applying results from small group to the general population E. The study did not carry on for a long period (no time to see long-term effects) F. Other problems not listed

1. A researcher working for an herbal medicine company conducts an experiment on 10 middleaged men. He tells them that he is testing an herbal medication that scientists think will make people feel more energetic. He instructs them to take one herbal medicine tablet a day for one week. After a week he asks them if they feel more energetic. He reports that 9 out of 10 people feel more energetic after taking the medication. Would you buy this medication? Explain why or why not. 2. Scientists have discovered a medicine that they feel has the potential to cure a deadly form of childhood cancer. They need to test the medicine to be sure that it is safe and effective. Should they test this medicine on animals before they begin tests on humans? Explain why or why not. 3. Parkinson's disease is a progressive neurological disease that gradually destroys a person's control of voluntary movements. Scientists have tested a treatment for Parkinson's disease in monkeys who showed disease symptoms. They drilled holes in the skulls of two randomly selected groups of monkeys. The experimental group had fetal tissue injected into their brains. The control group had distilled water injected into their brains. The treatment was 80% effective in treating the symptoms of the disease in monkeys. You have recently been diagnosed as having Parkinson's disease. Researchers have asked you to participate in their clinical trials to test the fetal tissue transplant treatment. Would you agree to become a subject in these clinical trials? Explain why or why not. 4. Scientists are conducting a long-term (3-year) double-blind placebo-controlled clinical trial on a chemotherapy they hope will cure prostate cancer. They want to determine if the chemotherapy is safe and effective. They randomly assign patients to be members of the experimental or control group. After six months they found that early treatment with the chemotherapy results in a 90% cure rate with no dangerous side effects. Should they offer the medicine to people in the control group now or continue the research as planned? Explain why or why not. 5. Testing and FDA approval are not required for natural herbal medications such as Ginkgo biloba, St. John's wort, and ginseng. Do you think people should use medicines that don't have FDA approval? Explain why or why not.

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Analyzing the Scientific Method: Case Studies
Many of the decisions about the foods we eat, the medicines we take, and the activities we participate in are based, in part, upon health information. Some of this information comes from well-executed studies that adhere to the scientific method, but some comes from flawed investigations. For the following real-life examples, decide whether or not the scientific method was followed. If it was not, indicate which of the following specific faults (A-F) was present and fully explain your reasoning. Case # One: Running during Pregnancy "I ran 4 miles (approximately 6 kilometers) every morning when I was pregnant with my first child," the woman told her physician, "and Jamie weighed only 3 pounds (approximately I kilogram) at birth. This time, 1 didn't exercise at all, and Jamie's sister weighed 8 pounds (approximately 3 kilograms). Therefore, running during pregnancy must cause low birth weight". Your Interpretation: Case #Two : Oat Bran and Cholesterol 500 Caucasian men who had hypercholesterolemia, with blood cholesterol levels between 300 and 400, were selected for a clinical study. All of the men were between ages 30-50, and worked white-collar jobs in the Midwestern states. Half of the group were given a standard diet which included 5 cups of oat bran daily. Half of the group were given a standard diet plan with no oat bran. All of the men had blood cholesterol levels tested by objective hospitals at the beginning and end of the study. After two months, the group who had eaten oat bran had a 20% decrease in their cholesterol levels. The group who had not eaten any oat bran had no change in cholesterol levels. The cereal company conducting the study concluded that if all people ate oat bran daily, their cholesterol levels would decrease. (And immediately started to advertise that!) Your Interpretation: Case #Three : Toxics at Love Canal A dumping site in the small town of Love Canal, New York, was used for the disposal of industrial chemical wastes from 1970-1975. In 1980, the housing inspector noticed traces of toxic substances in the basement walls of the local schools and homes. The local hospital noticed that there were 25% higher numbers of birth defects during 1970-1980. The hospital then offered free genetic tests and found that 20% of the adult volunteers/residents of Love Canal contained genetic abnormalities. The exposure to those industrial chemical wastes must have been the cause the genetic abnormalities and higher birth defect incidence. Your Interpretation: Case #Four : Cancer Researcher A former National Cancer Institute (NCI) researcher was bothered by the practice of turning down large number of cancer patients who wanted to participate in clinical trials. His solution was to leave the institute and start his own company, which offers to do research on individuals' tumors. This research could lead to personalized experimental treatments. However, this researcher's company is not supported by government funds, so patients have to pay for the research service - about $60,000 a year. The company publishes the results of its research. Your Interpretation

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Case #Five: Vasectomy Each year, 500,000 American males join the 10 million who have already had a vasectomy, a simple sterilization procedure. In the early 1970's, animal studies suggested that heart disease might be a complication of vasectomy. To test this hypothesis, a study involving more than 20,000 men was begun. In this study, each of 10,000 vasectomized men was paired with a nonvasectomized man of the same age, race and marital status and living in the same neighborhood at the time of the surgery. Each man was extensively questioned about medical conditions (including 54 conditions statistically most likely to be associated with vasectomy) and health and life-style habits, such as smoking, drinking, diet, exercise, and frequency of checkups. Medical records were carefully evaluated. The results of this study showed that vasectomized men had no significantly higher rates from any of the health conditions examined. Conclusion: vasectomy is safe. Your Interpretation:

Case #Six : Cancer Trials The National Cancer Institute (NCI) sponsors clinical trials at its Maryland headquarters and in several research hospitals around the country. New treatments are carried out on human cancer patients and the results evaluated. Standard cancer treatments are used as controls. There are many more cancer patients seeking to participate in these trials than there are spaces available for them. The policy of the NCI is to select the healthiest, strongest patients possible - what one cancer researcher calls "the perfect patient", The goal is to give the new treatment the maximum chance of working by testing it on a patient who has cancer but is otherwise young, strong, and healthy. Whenever results of such trials seem promising, television new shows excitedly announce them as "breakthroughs". Your Interpretation:

Case #Seven : Pyruvate & Weight Loss A study conducted at the U. Pittsburgh School of Medicine found that obese women who were given pyruvate supplements for three weeks lost an average of 13 pounds weight (of which 8.8 pounds was fatty tissue). During the study, the subjects were on a liquid diet consisting of 1000 calories per day and were ingesting 30 grams of pyruvate daily. The control group consumed an equal amount of carbohydrates (instead of pyruvate) on a solid diet. One health and nutrition store wants to start selling pyruvate as "a phenomenal weight-loss pill for overweight women". Your Interpretation:

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