In a recent electronics lab, we designed a simple circuit consisting of only three resistors and a battery. After recording all the relevant data for the system (I, V drop, R, etc), we then grounded it by attaching a wire from one of the resistors to a metal bolt attached to a nearby water pipe. Doing so caused none of our values to change, which the TA said was expected. I'm assuming this is because the water pipe never fed back into the circuit meaning the loop wasn't complete (i.e. the wire from the circuit to the pipe was essentially "dangling" out from our circuit). Basically, I just wanted to check to make sure this was a valid assumption.