A couple of days ago, my daughter was late for school because she idly asked me how to skip stones across water. As a fervent stone skipper, I lost all track of what we should have been doing (going to school) and spent a good half hour searching for appropriate stones and then practicing our techniques on the river. I'm not sure if this makes me a great mum or a really horrible one, but interestingly, New Scientist reports that a French physicist has reduced the pastime to a mathematical formula.

Damn. If I'd only known, I could have told the headteacher we were late because we were conducting experiments in advanced physics.