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

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 system can do mechanical work 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 second video this is more than obvious), in violation of the second law of thermodynamics.

Pentcho Valev