Variations on Aristotle's theory that the elements of matter comprise earth, air, fire, and water persisted for centuries, as illustrated in this diagram from the late fifteenth century.
Reproduced from the collections of the Library of Congress
Ivars Peterson is a freelance writer and editor. He was Director of Publications at the Mathematical Association of America from 2007 to 2014. As an award-winning mathematics writer, he previously worked at Science News for more than 25 years and served as editor of Science News Online and Science News for Kids. His books include The Mathematical Tourist, Islands of Truth, Newton's Clock, and Fragments of Infinity: A Kaleidoscope of Math and Art.