Evaluating Scientific Explanations Answers

Error bars on four different data points are shown below.Which of these data points is the most reliable?

A ruler has markings as shown below. Stefan uses this ruler to measure the length of a metal rod. How many decimal places should his answer include?

Which quantity is used to generate the error bars on a graph?

Which of the following best specifies the purpose of error bars on a graph?

Precision can be defined as the

Rob measures the solubility of three different salts in water at 22°C. Which type of graph should he use to display his data?

How can one determine the median of a data set?

A teacher uses a bow and arrow to demonstrate accuracy and precision. She shoots several arrows, aiming at the exact center of the target each time. The drawing below shows where her arrows hit the target.Which statement best describes her shots?

Which property of a measurement is best estimated from the percent error?

Jose’s lab instructor gives him a solution of sodium phosphate that is buffered to a pH of 4. Because of an error that he made while calibrating the pH meter, Jose’s measurements of the pH of the sodium phosphate solution are 5.4, 5.4, and 5.4. Which statement best describes his results?

Which source is most likely an authority on the subject?

Read the claim.Breakfast is an important meal. It jump starts the body’s process of using calories to break down food. Appetite can decrease with age, but going too long without eating causes metabolism to slow down. Current research shows that incorporating legumes such as lentils and chickpeas into meals boosts metabolism for twenty-four hours.

Cookware companies have been using a chemical called C-8, which helps to create a nonstick coating to pans. However, the Environmental Protection Agency (EPA) recently claimed that the use of C-8 in the manufacturing of nonstick cookware should be discontinued because studies show it causes cancer.

Sharon reads two different articles about avocados. The first article, in a weight-loss magazine, claims that avocados are unhealthy because they are high in fat. The second article, in an annual publication from a doctors’ group, claims that the fat in avocados is a type that is good for the heart.To assess these claims, which question might Sharon ask?

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.

Which factor is found in a scientific claim?

Which is one way that scientists ensure that data is reliable?

Which is an unreliable source?

Read the article by Michael Fumento, writer for the New York Post editorial blog, who does not support global warming.Back in 2005 I and others reviewed the entire hurricane record, which goes back over a century, and found no increase of any kind. Yes, we sometimes get bad storms—but no frequently now than in the past. The advocates simply ignored that evidence.Fact is, the earth was cooling and warming long before greenhouse gases could have been a factor. The [global warming supporters] have been proved wrong time and time again.

If peers accept a scientific paper’s claim, what is the next step in the process?