E.g. I fill a bowl with hot water and then place a ball in it, the ball will heat up. Does the rate at which the ball heats up change if that ball is spinning on the surface or moving around in the water, vs. sitting still?
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Probably, but it may depend on what the ball is made of, since it might also affect how fast the heat transfers out of the ball into the air.
When something moves within a fluid, even just spinning in place, it moves the fluid around it. That results in convection, in this case, moving the water that has just dumped its heat into the ball away and replacing it with still-hot water. But the reverse would happen, too, with air. Remember, in physics, the term “fluid” refers to liquid *and* gas. So the air gets convected around, too, carrying heat away from the ball. Which one wins out, and how quickly, depends on the specific heat capacity of the ball, how deep it floats, and even which way it’s spinning (if it spins vertically, it would carry water up onto the air side as it turns, insulating it from the air a bit.
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