Replication vs. Repetition

Reggie and Marissa decide to measure the number of stairs a spring toy can travel down. Reggie tries first. Before he tells Marissa what he measured, however, he tries the experiment three different times. When Marissa asks about the result, he tells her the average of his three trials, and the range of his results, from the lowest to the highest value. What would be the most likely scientific reason for Reggie to repeat the experiment so many times?

• He needed to obtain identical results.

• He needed to obtain the result he expected.

• He needed to see how consistent or inconsistent his results were.

• He needed to see how the fundamental principle he was studying changed.

Which statement is necessary in order for a scientific investigation to be valid?

• The investigation must be able to be repeated by others.

• The investigation must produce data that can be graphed.

• The investigation must follow all the steps of the scientific method.

• The investigation must have a conclusion that matches the prediction.

Tags

NGSS.MS-PS2-5

What happens if the results of a scientist's experiment are NOT similar to the results gathered by other scientists doing the same experiment at a later date?

• The results of the experiment are changed by the scientists.

• The results of the experiment are published in scientific journals.

• The results of the experiment are questioned by the other scientists.

• The results of the experiment are accepted by the scientific community.

Marvin predicts that if marigold flowers are planted around a group of tomato plants, then fewer insects will eat the tomatoes. Which of the following observations would best support Marvin's prediction?

• A count of 20 insects before marigolds are planted and 20 insects after marigolds are planted.

• A count of 20 insects before marigolds are planted and 12 insects after marigolds are planted.

• A count of 10 tomato plants before marigolds are planted and 5 tomato plants after marigolds are planted.

• A count of 10 tomato plants before marigolds are planted and 15 tomato plants after marigolds are planted.

In science class, Lisa just finished investigating the growth of mold. She stored a piece of white sandwich bread in a plastic bag and made pictures to keep records of the amount of mold after 3 days, after 6 days, and after 9 days. Which statement is an observation rather than opinion?

• The picture after 9 days shows the most mold.

• White sandwich bread would have more mold if stored in the dark.

• Whole wheat bread would have had less mold than the white bread.

• . A picture drawn after 10 days would show much more mold than on day 9.

Jorge and Nancy conducted an experiment together. They caught moths that were attracted to either white light or yellow light and recorded the data. Their results are shown in the graph below

Which of the following conclusions is valid based on the graph?

• captured moths prefer yellow light

• only white moths are attracted to white light

• the number of moths captured per day using white light decreased each day

• the number of moths captured per day using yellow light decreased after day 5

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4