Why doesn't a ceramic coffee cup keep coffee hot for very long?
Actually coffee does not stay hotter in a ceramic cup vs a Styrofoam cup, but would stay hotter in a ceramic cup vs a paper cup.A good insulator for a water based liquid will reduce conduction and convection. Styrofoam works well keeping coffee warm because it has a small mass and a large volume. The small mass helps eliminate conduction. The large volume is because the sintering process traps tiny pockets of air that help eliminate convection. With those two together you get hot coffee longer.