Jimmy’s favorite hobby is using his telescope to look at the stars. He has noticed that constellations are in different locations during different times of the year. For example, the Big Dipper is visible in his backyard in the summer and the front yard in the winter. Which type of investigation would Jimmy need to conduct to figure out why this happens?

A. Experimental
Incorrect. He does not need to manipulate variables or conduct a test.

B. Comparative
Correct! He is comparing the locations of constellations at different times of the year.

C. Descriptive
Incorrect. He is comparing, not just describing with senses or measurements.

D. Associative
Incorrect. There is no such type of experiment as associative.

Read the following lab scenario.

In order to determine the best temperature for bacterial growth, a scientist placed samples of the same type of bacteria in 4 petri dishes and supplied them with equal amounts of nutrients, oxygen, and light. The petri dishes were placed in areas with controlled temperatures. The temperature was maintained at 20°C, 22°C, 24°C, and 26°C. After three weeks of observations, the scientist determined that the highest rate of bacterial growth occurred at 24°C.

The independent variable in this experiment is the —

A. length of the experiment
Incorrect. The length of the experiment has no effect on the outcome of this experiment.

B. number of bacteria
Incorrect. The number of bacteria depends on other factors in the experiment.

C. reproduction rate
Incorrect. Reproduction rate depends on other factors in the experiment.

D. temperature
Correct! The temperature is the variable that determines the rate of growth of the bacteria.

Read the following lab scenario.

In order to determine the best temperature for bacterial growth, a scientist placed samples of the same type of bacteria in 4 petri dishes and supplied them with equal amounts of nutrients, oxygen, and light. The petri dishes were placed in areas with controlled temperatures. The temperature was maintained at 20°C, 22°C, 24°C, and 26°C. After three weeks of observations, the scientist determined that the highest rate of bacterial growth occurred at 24°C.

Which of the following is NOT a constant in the experiment?

A. Type of bacteria
Incorrect. The description of the experiment states the same type of bacteria was used therefore this is a constant.

B. Amount of oxygen
Incorrect. The description of the experiment states that equal amounts of oxygen was supplied therefore this is a constant.

C. Growth rate
Correct! Growth Rate is the dependent variable therefore it is not a constant.

D. Amount of light
Incorrect. The description of the experiment states that equal amounts of light was supplied therefore this is a constant.

The statement is a poor hypothesis because it is not —

A. a question
Incorrect. A question would be formed during the observation phase.

B. testable
Correct! A hypothesis is a tentative statement that proposes a possible explanation to some phenomenon or event. This statement would explain how two variables are related.

C. observable
Incorrect. A hypothesis is formed after observations are made.

D. a comparison
Incorrect. A hypothesis does not have to be a comparison.

Which of the following is a characteristic of a hypothesis?

A. Testable
Incorrect. This is a characteristic, but are there others on the list?

B. Possible answer to a scientific question
Incorrect. This is a characteristic, but are there others on the list?

C. Follows observations and research
Incorrect. This is a characteristic, but are there others on the list?

D. All of the above
Correct! These are all characteristics of a hypothesis.