Science and the Scientific Method



BUGGO: Science and the Scientific Method

Purpose: Students will become familiar with the means by which scientific information is gathered.

Materials: Paper and pencil

Introduction: Science is more than a body of information. Science is dynamic—it constantly grows and changes. Scientists carry on an unending search for new information. With that new information, they reevaluate old information to find out whether it is still valid.

The scientific method offers a means of testing ideas and solving problems experimentation is the foundation upon which science rests, and experimentation is the heart of the scientific method. This lab gives you the opportunity to develop skill in using the scientific method.

In order to understand how to set up experiments, you must first become familiar with the following terminology:

• Assumption—a statement accepted without proof

• Hypothesis—an idea used as the basis for experimentation. A hypothesis is expressed as a positive statement and is usually only one sentence long. If the hypothesis is correct, then such and such should happen. The “such and such” is the deduction. It normally determines how an experiment will be designed.

• Controlled experiment—the procedure designed to determine whether an idea—the hypothesis—is true or false.

• Experiment—the test in the controlled experiment. The experiment tests only one factor, as stated in the hypothesis.

• Independent Variable—the single factor that the experimenter tests

• Dependent Variable—the response observed by the experimenter thought to be caused by the independent variable

• Control—the standard of comparison for the experiment. All factors in the control are the same as in the experiment, except for the one factor tested in the experiment

• Fact—something that is observed

• Data—the facts collected during the experiment

• Analysis—the interpretation of the data, or what the data mean

• Conclusion—whether the hypothesis has been supported by the data. The conclusion of a controlled experiment is one of the following:

▪ The data support the hypothesis or

▪ The data do not support the hypothesis.

The following fictional experiment demonstrates the use of the scientific method.

Many people in the small Midwestern town of Hootville are stricken with the disease “Buggo.” Most of those stricken recover within seven to nine days.

Buggo has been shown to be caused by a bacterium called “Gotcha.” Antibiotic “X” is a new drug that has been shown to kill Gotcha bacteria cultured in a test tube. Antibiotic X was also found to cure dogs that were stricken with Buggo.

Researchers decided to test the new drug on some of the people in Hootville. They hypothesized that the

drug would effectively cure Buggo in humans. They deduced that if they gave patients antibiotic X, the patients would recover more quickly than those who did not take the antibiotic.

The researchers prepared tablets containing antibiotic X. They also prepared a second batch of tablet that did not have antibiotic X. a tablet that does not contain any medication is called a placebo.

The researchers selected two groups of people who had just contracted the disease. Selected two groups of people who had just contracted the disease. Twenty-five people in group A were given the tables containing the drug. Twenty-five people in group B were given the placebos.

Twenty of the twenty-five people given the drug recovered within one day. The other five people in group A took from 7-9 days to recover—the normal recovery time for untreated patients. One of the people given the placebo recovered within one day. The rest of the people in group B took from 7-9 days to recover.

1. Name 3 facts that were known before the start of the experiment.

2. One assumption is, “Antibiotic X is not lethal to humans.” List 2 other assumptions.

3. Sate the researchers’ hypothesis.

4. List one other hypothesis.

5. What are the (a) independent variable and the (b) dependent variable?

6. How do the experiment and the control differ in this controlled experiment?

7. What are the data in this experiment?

8. What analysis do you think the researchers made of the data?

9. What conclusion do you think they reached?

Now it is your turn. Design an experiment to test the effect of fertilizer on bean production in bean plants.

The story is:

Bean growers want to increase crop yields to meet the growing demand for food. The Acme Fertilizer Company has asked a botanist—you—to test their latest product, Growmore, on bean production.

10. Design an experiment to test Growmore.

11. What assumptions did you make?

12. What is the hypothesis for your experiment?

13. What are the (a) independent variable and (b) dependent variable?

14. What is your experimental control?

15. What would the data look like if they supported the hypothesis?

Analysis

16. In a controlled experiment, why is there only one experimental variable?

17. What would happen if there were more than one variable?

18. Why is a control necessary?

19. What does a controlled experiment provide to help you solve a problem?

20. In the Buggo case, why did the researchers first test antibiotic X on a small group,

instead of giving it to everyone in town who had the disease?

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