# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Stone skimming formula adds new spin," by Hazel Muir. *New Scientist,* 16 October 2002.

Skimming stones on the surface of a lake fascinates children and adults alike. Now a French physicist, Lydéric Bocquet of Lyon University, has developed a set of mathematical equations describing how stones skim over water. The equations allowed him to calculate the minimum speed the stone needs to be traveling in order to skim. "[T]he equations also backed his hunch that spin is important becuase it keeps the stone fairly flat from one bounce to the next," the article states. Bocquet's article on the subject will appear in the *American Journal of Physics.*

*--- Allyn Jackson*