Best-selling author Sam Kean stops by Reactions this week to debunk the myth of the Megalodon, the 50-foot super shark that, despite what "Shark Week" may lead you to believe, is long-extinct. 

Kean's book, "The Disappearing Spoon: And Other True Tales of Madness, Love and the History of the World from the Periodic Table of the Elements," is getting the Reactions treatment in a video series produced for the newly launched American Association of Chemistry Teachers (AACT). In this episode, Kean unravels the myth of a living Megalodon, explaining how the element manganese holds the key.