I have read about the Earth's sorting of different-sized grains of sand and such. Larger particles are supposed to fall through water faster. I've seen it demonstrated before and have full faith. But this morning, on emptying my French press carafe, I was puzzled on seeing that the finer (smaller) coffee grounds had settled, and always do seem to settle (each morning) beneath the coarser (larger) grounds. So,
can someone refresh me on gravity's sorting mechanism? I know it has to do with air- or fluid- resistance, surface-area-to-volume ratio, but I'm pretty rusty on the specifics. How would one account for all possible particle shapes? Or do we just assume perfect spheres?
Does anyone else use a French press? If so, have you noticed similar? If so, how do you fit that into this picture?