Review: Read each of the following statements. As you read each, state its converse. If a statement is a hypothesis, give the method of science by which it could be tested.

(a) method of repeated experimentation

(b) historical method

(c) the statement is not a scientific hypothesis

1. a b c The Grand Canyon was cut by the Colorado River.

2. a b c The composition of pyrite is one part iron and two parts sulfur.

3. a b c The Earth is only a few thousand years old.

4. a b c Most of Boulder, Colorado, lies in an area of flood hazard.

5. a b c Radiation is damaging to the cells of living animals.

6. a b c Casual exposure to asbestos poses a lethal hazard to many homeowners.

7. a b c Sound travels through clay soils at about 5,000 ft/sec.

8. a b c Radio City Music Hall in New York is haunted by two spirits.

9. a b c The climate in New Mexico a few thousand years ago was much like the climate found in Minnesota today.

10. a b c God created heaven and Earth.

1-b

The converse is that the canyon was NOT cut by the Colorado River. (All ten statements can be restated in the converse by similar use of the word "not.") To test for the best hypothesis, we would have to do field studies to learn if a river like the Colorado could cut a canyon like the Grand Canyon and if some other method of cutting canyons can be found that would provide a better explanation.

2-a

This statement is easily tested and replicated by laboratory experiments.

3-b

To test this would require a large number of field studies to decide whether the stated hypothesis or its converse best fits our growing knowledge about the Earth.

4-b

We would need to do field studies to look for evidence of flood deposits, old stream channels etc. that would be produced in an area with a history of intense flooding.

5-a

This statement is easily tested and replicated by laboratory experiments.

6-b

To prove this, we'd have to find a damaged population of homeowners who have died from diseases like lung cancer that can be clearly related to asbestos in their homes. To prove the converse, we'd have to keep data on an immense population of homeowners and verify that those with asbestos in their homes have no more lung cancer disease than the general populace.

7-a

This statement is easily tested by experiments in the laboratory or in the field.

8-c

The statement deals with the spiritual, not with the physical world. Even if it was true, it could not be resolved by the methods of science.

9-b

The hypothesis could be resolved if we can look at the record left in soil and rock. If we find plant and animal fossils that are compatible with a cooler, wetter climate like Minnesota's, then the hypothesis is supported; if we find no such fossils, the converse is supported.

10-a

The statement is not a hypothesis. It may be true or false, but it is not testable by the methods of science. It is important to note that if a statement does not deal entirely with the physical world and is not testable, then resolution of the truth of that statement cannot lie in the methods of science.