The Forces in Spilled Coffee Awaken

Like much of the world, scientists thrive on coffee. It's not just because of the caffeine though, it turns out that even spilled coffee fuels research.Most people are annoyed by nagging coffee stains, but to physicist Sidney Nagel they were inspiration. If you're a coffee lover (or you live with one), I guarantee that you've seen the characteristic light brown stain with dark edges. I assume it was after he'd already had his morning coffee that this color difference piqued Nagel's interest. The...