Folk tales tell that when the sun shines on a troll’s body, they rapidly transform to stone. In Tolkein’s work, trolls also turn to stone (the famous example being in The Hobbit). The Samoyedic peoples of Russia (just west of the Ural mountains) have a similar story about giants, and it is tied to seven, […]
The physics of skipping stones across water has been studied by many. One engineer in particular wrote a book on the subject: The Secrets of Stone Skipping. For nearly three decades, Jerdone Coleman studied stone skipping in a huge variety of conditions, even working with MIT’s Strobe Project Lab to photograph the stones in motion.