The finished sculpture is documented over here.
It also has a life of it's own and reacts to the sounds in the room.
Brain: Arduino microcontroller.
Ear: Electret condenser microphone with a simple amplifier.
Hand: An old printer motor rotates excentrically and shakes the bubble to create ripples.
Look at some old and inaccurate sketches:
Look at some prototypes:
The Motor with an excentric shaft
The Electronics (Arduino under custom shield)
And because you scrolled so far you'll get to look at some pretty and pretty funky caustic experiments:
Get in touch if you'd like some code or something.