Most Americans have a good grasp of some areas of scientific knowledge but are relatively clueless on others, according to Pew Research Center analysis based on a quiz that you may wish to try out here before reading on—and if you get a perfect score, congratulate yourself on being among the top 6% in the country. Out of the 12 multiple-choice questions that Pew describes as representing a "small slice of scientific knowledge," the 3,278 randomly selected adults found one on the Earth's layers the easiest, with 86% correctly naming the core as the hottest. Only 34%, however, knew that water boils at a lower temperature at higher altitudes, and only 35% knew that the height, or amplitude, of a sound wave determines its loudness.
The average number of questions answered correctly was eight, though this tended to go up with the respondent's education level. Pew says that men tended to get higher scores than women, white people tended to score higher than other groups, and younger adults tended to do better than those over 65—but while under-30s were more likely to identify radio waves as the waves that transmit cellphone calls, fewer of the under-65s were able to identify Jonas Salk as the developer of the polio vaccine. Overall, the findings amount to a "D" in science for the nation, decides Karen Kaplan at the Los Angeles Times, who notes that a disappointing 22% of respondents mixed up astrology and astronomy. (You almost definitely couldn't pass this wild Indian exam.)