There are substantial differences among Americans when it comes to knowledge and understanding of science topics, especially by educational levels as well as by gender, age, race and ethnicity, according to a new Pew Research Center report. The representative survey of more than 3,200 U.S. adults finds that, on the 12 multiple-choice questions asked, Americans gave more correct than incorrect answers. The median was eight correct answers out of 12 (mean 7.9). Some 27% answered eight or nine questions correctly, while another 26% answered 10 or 11 items correctly. Just 6% of respondents got a perfect score.

Most Americans (86%) correctly identify the Earth's inner layer, the core, as its hottest part, and nearly as many (82%) know uranium is needed to make nuclear energy and nuclear weapons.

Americans fare well as a whole when it comes to one aspect of science history: Fully 74% of Americans correctly identify Jonas Salk as the person who developed the polio vaccine from among a list of other scientists that included Marie Curie, Albert Einstein and Isaac Newton. 

And most Americans can distinguish between astronomy and astrology. Seventy-three percent of adults recognize the definition of astrology as the study of how the position of the stars and planets can influence human behavior. By comparison, 22% of adults incorrectly associate this definition with astronomy, while another 5% give some other incorrect response. 

But other science-related terms and applications are not as well understood. Far fewer are able to identify the property of a sound wave that determines loudness. Just 35% correctly answer amplitude, or height. Some 33% incorrectly say it is frequency and 23% say it is wavelength. And just 34% correctly state that water boils at a lower temperature in a high-altitude setting (Denver) compared with its boiling point near sea level (Los Angeles). 

"As science issues become ever-more tied to policy questions, there are important insights that come from exploring how much Americans know about science," said lead author Cary Funk, an associate director of research at Pew Research Center. "Science encompasses a vast array of fields and information. These data provide a fresh snapshot of what the public knows about some new and some older scientific developments - a mixture of textbook principles covered in K-12 education and topics discussed in the news."

The data show that adults with higher education levels are more likely to answer questions about science correctly. In this survey, education proves to be a major factor distinguishing higher performers. While the questions asked relate to a small slice of science topics, there are sizeable differences by education on all 12 multiple-choice questions. This pattern is consistent with a 2013 Pew Research Center report on this topic and with analysis of the factual knowledge index in the National Science Board's Science and Engineering Indicators.