Question

In other cases, researchers use natural experiments in which the dependent variable (typically a measure of organism health) is measured under differing contexts that are not manipulated. Say, for example, that an accidental chemical spill contaminates five ponds. To determine the possible effects of the toxic chemical on frogs, a researcher could compare the hatching rate of frog eggs laid in those five ponds to the hatching rate of eggs laid in five uncontaminated ponds nearby. This would be an example of a natural experiment because concentrations of the toxic chemical in the ponds were not controlled by the experimenter, but rather resulted from the chemical spill.

Drag type of experiment on the left to the example of experiment on the right.
A. Natural
B. Manipulative
1. ______: Blood concentrations of BPA in college students are compared to their recent consumption of canned food items
2. _____: The feeding behavior of fish in streams that receive acidic runoff from strip mines is compared to the feeding behavior of fish in unaffected streams.
3. _____: The deformity rate in baby birds from nests in pesticide-sprayed fields is compared to the deformity rate in birds from nests in unsprayed fields.
4 ______: Tumor development is compared in mice exposed to five dosages of a known carcinogen in the laboratory.
5. ______: Foraging activity levels are compared in tadpoles exposed to four concentrations of toxic metals in the laboratory.
6. ______: Growth of corn plants is compared in field plots sprayed with three different dosage:s of weed killer 7.
7. ______: BPA concentrations in the urine of people with diabetes are compared to BPA concentrations in the urine of people without diabetes

Answer 1

1. Natural

2. Natural

3. Manipulative

4. Manipulative

5. Manipulative

6. Manipulative

7. Natural

Step-by-step explanation:

1. Checking the blood concentration of BPA in college students in relation to their recent consumption of canned food items is a natural experiment because BPA concentration in blood is not artificially controlled by any means.

2. Comparing the feeding behavior of fish in streams with acidic runoff to that of fish in an unaffected stream is a natural experiment due to the fact that the acidity of the stream is not artificially controlled in any way by the experimenter.

3. Checking the deformity rate in baby birds from nests in pesticide-sprayed fields and that from unsprayed fields would require some manipulations except a sprayed and unsprayed one already existed long before the experiment was given birth to. Otherwise, the sprayed field might need to be artificially created just for the purpose of the experiment.

4. A known carcinogen would need to be administered to a group of the mice. This is manipulative.

5. The tadpoles would need to be artificially exposed to the toxic metals in the laboratory. Manipulative

6. The spraying would need to be carried out artificially in order for the comparison to be made. Manipulative

7. People with diabetes cannot be artificially created. They must have existed naturally long before the experimental design. Natural