Why Are Coffee Stains Darkest at the Edges?
2025-05-13
Halldór Svavarsson, associate professor at the School of Technology and Engineering at the University of Reykjavik, Iceland, posed the question of why coffee stains are darkest at the edges when they dry. The provided text doesn't offer an explanation, only presenting the question and author information, suggesting a scientific answer is needed, beyond simple observation.