I have been thinking about the (several) Joule mechanical-equivalent-of-heat
experiments. Joule seems to have used a container of water with a few flat
brass paddles which were rotated on a vertical shaft to stir and
consequently heat the water.
Does the Entropy increase during this experiment???
Would the Entropy increase if this were done with an ideal gas as the fluid?
If this gas were sqished with a piston instead, would the Entropy increase?