I've did something similar when I was around 14 or 15 years old.
I filled a standard wall-mounted, ceramic sink filled with regular tap water. I then took a lamp cord with about an inch of bare wire exposed on each of the two conductors and place the two conductors into the water about 8-9 inches apart. Nothing happened. I began pulling the wires closer together until at about 1/2" there was a pop, a flash of light and then black residue (burned copper from the exposed conductors). The breaker didn't trip.