Water rises and then goes down as the capacitor is switched on and off:

"Physics Demonstration of the Force on a liquid dielectric in an electric field" https://www.youtube.com/watch?v=Cs8nAeJZeWc

"Liquid Dielectric Capacitor" https://www.youtube.com/watch?v=T6KAH1JpdPg

"Rise in level of liquid dielectric in capacitance" https://www.youtube.com/watch?v=uHNmzcYp6JE&t=358s

The systems can do mechanical work - e.g. by regularly lifting floating weights. The work will be done at the expense of ambient heat (clearly not at the expense of electric energy - in the last video this is more than obvious), in violation of the second law of thermodynamics.

Pentcho Valev