When I poured the little plastic thingie of creamer into my coffee, I didn't stir it immediately. I was a little surprised that it then separated into a thick layer of "coffee-with-cream" in the bottom of the cup, and a thin layer of "coffee-with-dramatically-less-cream" on top of it. (I can tell this because I have an
awesome beaker mug).
That was 15 minutes ago. Apparently the ability to accurately measure the height of different strata in my coffee column is more interesting than drinking the coffee, because I haven't touched it yet. For what it's worth, the cream layer seems to be separating into two substrata, and the cream that was in the top layer may be floating to the top of that layer, but the two main strata aren't mixing.
ETA: Having noticed no changes for a period of time, I decided to microwave the coffee and drink it. In the process of carrying it to and from the microwave, I didn't disturb the layers overly much, but I must have sloshed it a bit because now there's a really fascinating, complex oscillation at the boundary between the "cream" and "less cream" layers, and the bottom sublayer in the "cream" layer is much shallower but dramatically denser. Again, I find myself watching my coffee cup rather than drinking the coffee. If I'm this distractable today, I'm in deep trouble.
ETA again: And the oscillation eventually served to mix the top two layers. There's now one large "medium cream" layer on top of a thin "serious cream" layer. Did I miss my calling as a geologist? Anyways. I'm stirring the cup FOR REAL this time. Or maybe I'll just see if I can drink it without disturbing the layers...
ETA, and finis: Empirical evidence (by which I mean my tongue) suggests that the difference between the "medium cream" and "serious cream" layers was the presence of artificial sweetener, which is, of course, carried along with a certain amount of starchy packet-filler, which also did not get stirred. Assumption: something in the non-dairy creamer got bound to the starchy packet-filler, which then vaguely sank; being heated intensified the effect. (Bored? Nerdy? Why, yes, yes I am....).