Evaluating Scientific Explanations — Unit test Answers

Advancements in which field have increased the ability to store increasing amounts of data on electronic devices?

Why is it important to have a control group in an experimental investigation?

Which characteristic should a good scientific question have?

Read the passage about the fluoridation of drinking water.Since the early 1960s, fluoride has been added to many sources of drinking water to prevent cavities in teeth. This is called fluoridation. There are some who say that this is unnecessary and increases the risk of cancer.In 1993, the Subcommittee on Health Effects of Ingested Fluoride of the National Research Council, part of the National Academy of Sciences, conducted an extensive study about the link between fluoridated drinking water and increased cancer risk. The study included data from more than 50 human disease studies and six animal studies. The Subcommittee concluded that none of the data showed a link between fluoridated drinking water and cancer. A 1999 report by the CDC supported these findings. The CDC report concluded that studies so far have produced "no credible evidence” of a link between fluoridated drinking water and an increased risk for cancer.

Students are studying the changing concentration of carbon dioxide levels in different substances. They insert sensors into each substance and allow a device to graph the results.What are the students most likely using?

Vincent graduated from college with a degree in horticulture and now owns a local plant nursery. He maintains a blog titled, "How to Live a Happy Life,” and writes that people can lead happier lives by varying the routes they usually take home from work.

Look at the graph below.

Which is one reason why hydrogen is considered a better fuel source for cars?

Which data can be measured quantitatively?

View the spinner.

Which model is most likely used to predict a future event?

A company that manufactures cookware has conducted numerous trials to see which metal needs the least amount of energy (measured in Joules, J) to be raised to high temperatures, and records the averages in a table. Which claim will this company most likely make?

Gerard lives in a tropical region where the average annual temperature is 77°F and the average annual rainfall is more than 100 inches a year. He surveys 25 people in his neighborhood about items they regularly use and records the data into a table.

Scientists often work on projects for a long time and fail to see sources of error in their research. Which process allows an outside expert to look at the scientist’s project and point to sources of error?

Chet plans an experimental investigation to see how well a new fertilizer works on daisies. The fertilizer must be dissolved in water and delivered to the plants by spraying it onto the leaves and stems.To set up his control group for the experiment, Chet should leave out the