Scientific Method Review Questions

Repeating experiments improves the likelihood of accurate results because the overall results are

• less likely to prove the hypothesis correct.

• more likely to prove the hypothesis correct.

• less likely to be correct due to fewer errors being made.

• more likely to be correct due to fewer errors being made.

Graphs of the data from laboratory investigations are used to

• observe general trends in the data

• make the observed data more accurate

• prevent errors in measuring data

• help change the original data tables

Scientists have collected data that indicate Earth's temperature is in a warming trend. Many scientists believe this temperature increase may be caused by an increase in the amount of carbon dioxide in the atmosphere. The graph below shows the changes in global temperature and carbon dioxide levels from 1980 to 2005.

Based on the data in the graph, which of the following is the best prediction of what the carbon dioxide level will

be in the year 2020?

• 375 parts per million

• 385 parts per million

• 395 parts per million

• 405 parts per million

One hundred laboratory rats were used in a controlled study to determine the effect of aspirin on the frequency of heart attacks. Fifty rats were each given a daily injection containing 50 milligrams of aspirin for a period of 1 year. On a daily basis, each of the other 50 rats would most likely receive an

• oral dose of 100 mg of aspirin

• injection of 50 mg of water

• injection of 100 mg of aspirin

• oral dose of 50 mg of water

An antacid seltzer tablet is dropped into each of two glasses containing equal amounts of water. The temperature of the water is 50C in glass 1 and 10C in glass 2. In each glass, bubbles of gas are released as the tablet dissolves. It takes 30 seconds for the tablet to react completely in glass 1 and 100 seconds for the tablet to react completely in glass 2. From these results alone, one can conclude that

• temperature has no effect on the rate of chemical reactions

• increasing the volume of water increases the rate at which the antacid seltzer reacts with water

• the rate of chemical reactions doubles for every 10C increase in temperature

• the rate at which the antacid seltzer reacts with water is faster in hot water than in cold water

In a scientific investigation, after the question is defined, the next step is most likely

• formulating a hypothesis

• identifying needed equipment

• designing the experiment

• collecting the data

A student reported that a wilted stalk of celery became crisp when placed in a container of ice water. The student then suggested that water entered the stalk and made it crisp. This suggestion is considered to be

• a control

• a hypothesis

• an observation

• a variable

The graph shows the average growth rate for 38 pairs of newborn rats. One of each pair was injected with anterior pituitary extract. The other member of each pair served as a control. At 75 days, what was the average weight of the rats injected with pituitary extract?

• 65 grams

• 125 grams

• 200 grams

• 225 grams

A student reported that a wilted stalk of celery became crisp when placed in a container of ice water. The student's statement was based on

• a deduction

• a hypothesis

• a conclusion

• an observation

Which sequence should be followed when conducting a laboratory investigation?

• gather experimental data, make observations, form a conclusion, form a hypothesis

• define a problem, form a hypothesis, gather experimental data, form a conclusion

• form a hypothesis, form a conclusion, gather experimental data, define a problem

• make observations, gather experimental data, form a conclusion, state a problem