Nature of Science DOK2

Shannon developed an experiment to test how light affects the growth of mold on white bread. She conducted the experiment twice, and the results were different each time. What should she do?

• She should repeat the experiment.

• She should research the results of similar experiments, and attempt to get the same data.

• She should develop a new hypothesis.

• She should repeat the experiment without using a control group.

Jasmine performed an experiment three times and got conflicting results. Her teacher told her she needed to repeat the experiment many times. What is the best way to accomplish this?

• change at least one variable each time

• change several variables each time

• perform the experiment exactly the same way each time

• use different procedures each time

The scientific theory of evolution holds a group of statements to be true: that all life is related, that natural selection exists, and that the fittest individuals of a group will survive to reproduce. How is the scientific theory of evolution different than a claim made by an individual person?

• The scientific theory of evolution is not supported by data collected from research investigations.

• The scientific theory of evolution is supported by a great variety of data.

• The scientific theory of evolution was first developed by a group of researchers.

• The scientific theory of evolution is an opinion.

A mineral supplement designed to prevent the flu was given to two groups of people during a scientific study. Dosages of the supplement were measured in milligrams per day, as shown in the table.

After 10 weeks, neither group reported a case of the flu. Which action would have made the study provide useful data?

• It could have tested the supplement on both groups for 5 weeks instead of 10 weeks.

• It could have tested a third group that received 150 mg of the supplement.

• It could have tested only the group given 200 mg of the supplement.

• It could have tested a third group that did not receive the supplement.

Why do scientists consider any hypothesis valuable?

• A hypothesis may lead to further investigation even if it is disproved by the experiment.

• A hypothesis requires no further investigation if it is proved by the experiment.

• A hypothesis requires no further investigation.

• A hypothesis can be used to explain a conclusion even if it is disproved by the experiment.

A nutrient medium was prepared by mixing powdered agar with boiling distilled water. Some of the prepared medium was then placed in a sterile petri dish, covered, and allowed to solidify. The cover was then removed, and the agar was touched to a doorknob. The petri dish was covered again and incubated at 37°C. After 48 hours, bacterial growth was observed. The investigator concluded that bacteria on doorknobs cause disease. What error did the investigator make?

• The investigator covered the petri dish.

• The investigator did not show that the bacteria caused disease.

• The investigator used distilled water.

• The investigator did not incubate the materials at the proper temperature.

Juliana measures the outdoor temperature each day for a week at exactly 3:00 p.m. The temperatures she records are all between 25 degrees C and 30 degrees C. Juliana concludes that the climate of her area is tropical. What is the MOST important reason why her conclusion may NOT be correct?

• She did not calculate the humidity, air pressure, and wind conditions.

• She made her conclusion based only on temperature and did not include precipitation.

• She made her conclusion based on only one week of data instead of over a long period of time.

• She recorded the temperature at only one time of day instead of more often.

Raul wants to investigate how the angle of a ramp affects the speed of an object rolling down the ramp. He can conduct his investigation in a number of different ways. Which investigation should he perform?

• observe different bicyclists riding down hills of varying steepness

• observe videos of various objects rolling down hills and estimate the angle of the hill and the speed of the object

• perform an experiment in a lab in which the angle of the ramp is controlled and the speed of a rolling cart is measured

• record the time it takes one bicyclist to ride down hills of varying steepness

Which can happen if an investigation is NOT replicated?

• A scientist will not get recognition for his or her work.

• Flawed or faulty procedures in investigations do not get exposed.

• Scientists are confident in the results.

• Scientists will most likely use this investigation as evidence in future experiments.

In the 1800's, some scientists believed in the 'rainfall follows the plow' idea, which was that breaking prairie sod would allow rainfall to be absorbed into the soil and this moisture would evaporate, causing an increase in rainfall. Which would MOST LIKELY lead to this scientific idea being disproven and revised?

• a few people not believing in the idea any longer

• documentation of heavy rainfall in the 1800s in prairies

• severe droughts and improved climate data in 1800s

• taller crops being grown in the 1800s than in the 1700s