Scientific Methods — Unit test Answers

A series of experiments, which are repeated over and over, seem to suggest that a scientific theory is incorrect. What does this most likely mean?

In an investigation that uses the scientific method, which step immediately follows asking a question?

Yusef adds all of the values in his data set and then divides by the number of values in the set.What is Yusef most likely finding?

Which statement best describes the variables in a controlled experiment?

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.

Scientists described light as a wave because the results of many experiments with light demonstrated that light behaves as a wave. Light is now described as having properties of both a wave and a particle. What is the most likely reason why this change was made?

Which action do researchers take to make advances in science?

A student is creating a table that compares theories, hypotheses, and laws. TheoryHypothesisLawIs testable Is falsifiable Is used to make predictions Provides explanations In which row should the student enter “Yes” in the columns for Theory and Hypothesis only?

Anita is comparing the accepted value for a physical property to the value she measured in the laboratory. Which characteristic of her measured value is Anita most likely trying to evaluate?

Sarah carried out an experiment to test a hypothesis. Some of her data supported the hypothesis, but some refuted it. What is the best thing for Sarah to do next?

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?

Rita divides Avogadro’s number (approximately 6.02214 1023) by 2.055 to calculate the number of atoms in a sample. Which expression gives her result to the correct number of significant figures?

Which term best describes the important pieces of information that scientists gather and record during an experiment?

Rachel is performing an acid-base titration. She hopes to determine the concentration of an unknown acid solution to two decimal places. Which is the best tool to find the volume of the base that she needs to neutralize the acid?

Juana performs the calculation below.6.05 + 3.156 + 5.0How should she report the answer using the correct number of significant figures?