Anyway, I make coffee by pouring the ground coffee into a tea-strainer, as I'm not a wuss.
I could not but notice that the grounds exhibiting a compass-like behaviour, very much magnetism. See link to video evidence.
It's possible our fore-fathers in Ethiopia discovered this behaviour and used it navigate the forests.
I suggest that the new generation of the Eurofighter Typhoons should be equipped with such a cup of coffee grounds, in gimbals, so the planes can still navigate without GPS and/or despite EMP.-- not_morrison_rm, Apr 05 2018 Unexpected behavior of coffee grounds video https://drive.googl...6g4we5Wwwen6wwJykwS [not_morrison_rm, Apr 05 2018] Laminar flow https://www.youtube...watch?v=p08_KlTKP50 [2 fries shy of a happy meal, Apr 06 2018] This is the behavior of the entire fluid, not just the grounds. Inertia, you see.-- RayfordSteele, Apr 05 2018 I think it will be tricky to get the grounds to stay in the shape of a monogram. Perhaps you could write a monograph about it.-- MaxwellBuchanan, Apr 05 2018 Go easy, people; he hasn't drunk his coffee yet.-- pertinax, Apr 05 2018 MB, well spotted ..corrected
//This is the behavior of the entire fluid, not just the grounds.
RS
Hmm, that's what I thought. I tried it with water only, but no obvious pointing-ness. It still think it's the interaction 'tween grounds and the water.
Daringly, I tried with the just the grounds only, but they just stayed in the same place, no matter how far the cup was rotated.-- not_morrison_rm, Apr 05 2018 On a similar note, it's been found that if you glue the feet of a homing pigeon to a freely-moving record turntable, the RSPCA will press charges.-- MaxwellBuchanan, Apr 05 2018 //glue the feet of a homing pigeon
It's more practical to glue the pigeon's feet on opposite sides of the axis of rotation, as it'll stop the gramophone being pulled over.
But, glueing the feet near the edge of gramophone, you get a more precise idea of where it wants to go.
Have you tried 2 pigeons/gramophones some distance apart?-- not_morrison_rm, Apr 05 2018 <loud squauking and flapping/>
Yes.-- 8th of 7, Apr 05 2018 Hmm, reminds me of those submarine films, silent running, the hunting ships using triangulation.
Whose idea was it to put put triangles on submarines anyway, surely they could just put them in sound-proof boxes until the ships bog off?
You never see submarines kazooing these days.
<falls asleep again under a copy of the Telegraph>-- not_morrison_rm, Apr 05 2018 <Videoing [n_m_rm] using phone>
<Captain Ramius>
"Re-verify our range to target... one ping only."
</Captain Ramius>
PINGGGGG !
<copy of Telegraph flies into air/>
</Videoing [n_m_rm] using phone>
<scuttles off to post video on YouTube/>-- 8th of 7, Apr 05 2018 It's actually a little-known fact that the first sonar to be tested on a submarine used a microphone and a man with a child's Glockenspeil to generate its "pings".-- MaxwellBuchanan, Apr 05 2018 In a similar way, Captain Ramius's secret device was a triangle with four corners, to confuse the echo location systems of vessels hunting his sub.-- not_morrison_rm, Apr 05 2018 I've noticed this behaviour a few times myself.
//I tried it with water only, but no obvious pointing-ness.//
I think this was because there were no obvious visible specks in the water to make its lack of rotation clear. Try it with some pond water, preferably with bits of duckweed in it.
I agree with [RayfordSteele] - it's just inertia. There is very little frictional coupling between the cup and the bulk of the liquid inside it.
Another thing to try: put the cup in the centre of a turntable, or a potter's wheel, or something like that. Set it rotating and watch it. I expect you'll see the liquid gradually start to rotate over a period of time, as the very small amount of friction slowly sets it in motion. Next, stop the turntable, and watch the liquid continue to swirl for some time afterwards; this is the same process in reverse.-- Wrongfellow, Apr 06 2018 [link]Here's a really cool video on what you are seeing. Watch it to the end though.-- 2 fries shy of a happy meal, Apr 06 2018 random, halfbakery