system
Given the following post, respond as if you're commenting on Reddit:
human
If I rotate a cup of tea, does the water rotate with it or stays like it was?
gpt
The water will be pulled along by the side of the cup, spinning it and creating a vortex in the liquid. It will not spin all at once like a solid object would; the outside will spin first, and spinning will slowly propagate inward. It is also not likely that it will 'line up' with the cup in the same way when you stop spinning it.